Herb 12,3, impresum - anubih

UDK 63/66 ISSN 1840-0809
HERBOLOGIA
An International Journal on Weed Research and Control
Vol. 12, No. 3, October 2011

Issued by: The Academy of Sciences and Arts of Bosnia and Herzegovina
and The Weed Science Society of Bosnia and Herzegovina
Editorial Board
Paolo Barberi (Italy) Senka Milanova (Bulgaria)
Vladimir Borona (Ukraine) Shamsher S. Narwal (India
Daniela Chodova (Czech Republic) Zvonimir Ostojić (Croatia)
Mirha ðikić (B&H) Lidija Stefanović (Serbia)
Rabiaa Haouala (Tunisia) Taib Šarić (B&H)
Zoran Jovović (Montenegro) Dubravka Šoljan (B&H)
Gabriella Kazinczi (Hungary) Štefan Tyr (Slovakia)
Editor-in-Chief: Academician Prof. Taib Šarić
Technical Editor: Dr. Mirha ðikić
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CONTENTS
1. S. Barudanović, J. Kamberović: Weed vegetation on the shores of artificial
reservoirs of surface mining pits in the area of Tuzla.....................................................1
2. D. Šoljan: Sedum sarmentosum Bunge (Crassulaceae), an allochthonous species
in the flora of Bosnia and Herzegovina…………………………………………………...15
3. G. Bocci, F. Bigongiali, P. Bàrberi, A.C. Moonen: Comparison between digital
analysis methods for the estimation of vegetation cover in weed research……………….23
4. R. Nakova: Competition of wild mustard (Sinapis arvensis) in winter wheat…………….33
5. A.Ladhari, S. Achour, F. Omezzine, A. Rinez, M. Zakhama, R. Haouala: Antagonism
and synergy between extracts of Ulva lactuca L., Padina pavonica L. and Corallina
officinalis L………………………………………………………………………………..41
6. Z. Pacanoski: Weed control in newly seeded alfalfa (Medicago sativa l.) with
postemergence herbicides…………………………………………………………………55
7. A. Tanveer, M.A. Nadeem, M.S. Quddus, F. Elahi: Effect of formasulfuron +
isoxadifen-ethyl in combination with urea on maize weed control and yield…………….65
8. Ts. Dimitrova, A. Katova: Selectivity of some herbicides to crested wheatgrass
(Agropyron cristatum (L.) Gaertn) grown for seed production………….………………..73
9. I. S. Alsaadawi, A. A. Al-Temimi: Use of sunflower residues in combination
with sub-recommended dose of herbicides for weeds control in barley field…..………...83
10. V. Dragičević, M. Simić, M. Brankov, I. Spasojević, B. Kresović: Alterations of
phosphorus methabolism in maize inbred lines influenced by herbicides ……….……….93
11. Z. Pacanoski: Bioherbicides - a real or virtual measure for efficient weed control?........103
12. V. Nagy, E. Nádasy, É. Lehoczky: A study of the competitive ability of velvetleaf
(Abutilon theophrasti Medic.) in a field experiment in parsley…………………………115
13. A. Khan, I. A. Khan, R. Khan, S. Zarin: Allelopathic effects of Parthenium
Hysterophorus L. on seed germination and growth of soybean, mung bean and
maize………………………………………………………………………………….....129
Instruction to Authors in Herbologia…………….….................. ..........................................137
Referees in the Herbologia No. 12/2011................................................................................138
Page

Herbologia Vol. 12, No.3, 2011
WEED VEGETATION ON THE SHORES OF ARTIFICIAL
RESERVOIRS OF SURFACE MINING PITS IN THE AREA OF TUZLA
Senka Barudanovic 1 , Jasmina Kamberovie
1 Faculty of Science in Sarajevo, Ulica Zmaja od Bosne 33-35, 71000 Sarajevo,email:sebarudanovic@
gmail.com
2 Faculty of Science in Tuzla, Univerzitetska 4,
75000 Tuzla, e-mail: jasmina.kamberovic@untz.ba
Abstract
During surface mining, as a result of displacement and disruption of
water flows, there often occurs formation of smaller permanent reservoirs.
On the watersides of newly formed water bodies, plant communities are
established, whose structure is most frequently weed.
The aim of this paper is to study the structure and floristic
composition of weed communities that are formed on the littoral zones of
lakes in surface mining pits of Tuzla basin. Phytocoenological recordings
were carried out on the shores of lakes Suhodanj and Sjerkovaca in the year
2008. There was applied the method of Zurich-Montpelier school. The
collected plant material was herbarized and determined, after which we
performed biogeographical and ecological characterization of the identified
species.
A total of 42 plant species were determined, which make the
structure of the communities: Polygono-Bidentetum tripartitae (W. Koch 26)
Lohm. 50 and Xanthieto riparii-Chenopodietum rubri Lohm et Walth. in
Lohm 1950. According to the existing data, the identified communities have
inhabited the shores of these lakes for 25 years already. However, their
permanent composition, which consists mostly of weed species indicates a
slow succession and a weak progradation capacity for a more productive type
of ecosystem. The results show that the weed species in these communities
have a role of pioneer species.
Keywords: artificial reservoirs, open pits, weed communities, bioindicators,
pioneer species.
Introduction
Surface coal mining has resulted in the formation of many degraded
areas. Disposal of tailings leads to repartition of surface water flows, thus
forming smaller lakes. Large variations in water levels on the shores of these
reservoirs throughout the year, causes the development of vegetation adapted

Barudanovic and Kamberovic
to changing habitat conditions. Most often these habitats are overgrown with
weed plant communities from the class Bidentetea tripartiti.
A detailed review of the research of communities within the class
Bidentetea tripartiti in the world was given by Kiesslich et al. (2003). The
characteristics of this class communities in river valleys of Poland were
described by Stepien (2000). Detailed studies of ruderal flora and vegetation
in Bosnia and Herzegovina have been presented by Topali6-Trivunovi6
(2005), in which the author, among other things provides data on the
structure of communities in muddy banks of the river Vrbas. Sumati6 et al.
(2001) describe the community of Polygono-Bidentetum tripartitae (W. Koch
26) Lohm 50 in Bardaca.
Description of habitats in muddy river banks in Bosnia and
Herzegovina and a differentiation of the class Bidentetea tripartiti was given
in the ,Protection of Biodiversity of the Sava River Basin Floodplains"
project report (Redzi6 et al., 2009). The authors state that weed-nitrophylic
communities in littoral zones of large rivers belong to the alliances
Chenopodion rubri p.p. and Bidention tripartiti p.p., of the order Bidentetalia
tripartiti and the class Bidentetea tripartiti. Communities of the alliance
Bidention tripartiti include pioneer vegetation of wet nitrified habitats which
are flooded during high water levels, where during the summer develops an
abundant vegetation mostly with therophytes. The alliance Chenopodion
rubri includes pioneer vegetation of nitrified but ruderal habitats, with
optimal development during the summer period (Redzi6 et al., 2009). Data on
ruderal vegetation on the shores of artificial reservoirs of surface mining pits
in our country are extremely scarce (Barudanovi6 et Kamberovi6, 2008).
The aim of this paper is to study the structure and floristic
composition of weed communities which grow in littoral zones of newly
formed lakes in open pits of the Tuzla basin.
Investigated area
The survey of littoral weed vegetation was conducted on the lakes
Suhodanj and Sjerkovaca. Both lakes are located at open pits of the Durdevik
basin (Tuzla coal-mining basin, north-eastern Bosnia).
Suhodanj Lake is located at latitude 44°23'38··s, lmgitude
18°38'37'1, at 293 meters above sea level. The lake was formed in 1985, by
damming the creek with tailings material. Artificial dam of the lake is quite
porous, so water sinks through the levee, causing water levels to significantly
vary throughout the year. It has an area of 2.5 ha and maximum depth of 18
meters (Smaji6, 2007). Geological base of the lake is made of calcareous
marls (Kamberovi6, 2010). Littoral zone of the lake has relatively small
slope.
2

Weed vegetation on the shores of artificial reservoirs of surface mining pits in the ...
Figure 1. Lake Suhodanj
Sjerkovaca Lake is located at latitude 44 °23 "55 .... S, longitude
18°36"051:, at an altitude of 318 m. The lake was formed in 1982 by
embanking with tailings material and damming the creek which bears the
same name. The lake is supplied with water from smaller surface flows and it
loses water by sinking through the embankment on the north side. Water
level varies greatly during the year, in the summer months it reduces for
approximately 1.5 meter. Maximum depth of the lake is approximately 20.5
meters. The lake has a maximum length in the north - south direction
approximately 514 meters, and a maximum width in the direction of
southwest - northeast, approximately 276 meters. The geological background
of the lake's wider area is made of marls and serpentinites (Kamberovic,
2010). The shores of this lake have relatively large slope (approximately
30°).
Figure 2. Lake Sjerkovaca
3

Barudanovic and Kamberovic
Materials and methods
Field survey was conducted in the year 2008. Phytocoenological
recordings of littoral vegetation were carried out by Zurich-Montpelier
school (Braun-Blanquet, 1964) at three locations in three vegetation seasons.
Determination of plants was based on herbarium material according to the
following literature: Domac (1973), Javorka & Csapody (1979), Tutin et al.,
(1964-1993), Kremer (2005).
After the differentiation of plant communities according to Lakusic et
al. (1977) and Rodwell (2000), we conducted a biogeographical and
ecological characterization of the identified species. Floral elements and life
forms of plant species were determined according to Oberdorfer (1979).
Sociability of plant species and environmental factors (temperature,
humidity, soil acidity, nitrification, light, continentality and salinity) are
given according to Ellenberg (Borhidi, 1993).
Results
In the survey of weed vegetation of artificial lakes asserts were
identified 42 plant species within two plant communities:
1. Polygono-Bidentetum tripartitae (W. Koch 26) Lohm. 50
2. Xanthieto riparii-Chenopodietum rubri Lohm et Walth. in Lohm 1950.
The community Polygono-Bidentetum tripartitae (W. Koch 26)
Lohm. 50 is present at the lake Suhodanj and consists of 37 species.
Characteristic species of the association are Bidens tripartita L. and
Polygonum lapathifolium L. and Phalaris arundinacea L. while in the
summer aspect, noted for their dominance are Lycopus europaeus L., Mentha
pulegium L., Potentilla reptans L., Lythrum salicaria L. and Xanthium
strumarium subsp. strumarium x subsp. italicum.
The community Xanthieto riparii - Chenopodietum rubri Lohm et
Walth. in Lohm 1950. develops in the wider littoral area of the Lake
Sjerkovaca. As part of this community, during three vegetation seasons there
were determined 21 plant species. Dominant is Xanthium strumarium subsp.
strumarium x subsp. italicum (syn. Xanthium riparium Itzigs. & Hertsch), but
there are also present Lycopus europaeus L., Phalaris arundinacea L.,
Setaria viridis !L./ P.B., Ambrosia artemisiifolia L. and others.
4

Weed vegetation on the shores of artificial reservoirs of surface mining pits in ...
on the indicator values for moisture and nitrification of habitats. Thus,
habitats of the community Polygono-Bidentetum tripartitae are inhabited by
"plant species in non-drained, well-aerated soils (W = 7.48) and plant species
in mesotrophic habitats (N = 5.73)", while the other community consists of
"plant species in fresh soil (W = 6.88) in the habitats occasionally rich with
nutrients (N = 6.83Y' (Table 3, Figure 3).
Table 3. The average values of ecological indexes of the determined
association
Ecological T w R N L K
indexes/association
Polygono-Bidentetum 5.52 7.48 6.58 5.73 7.18 4.27
tripartitae
Xanthieto riparii- 5.56 6.88 6.52 6.83 7.26 4.45
Chenopodietum rubri
(T-temperature, W-humidity, R-soil acidity, N-Ditrification, L-ligbt. K-continemality, Ssalinity)
K
T
- Polygono­
Bidentettlm
tripartitae
R - Xanthieto riparii-
Chenopodiettlm wbri
Figure 3. Ecological analysis of the detennined association
The dominant life form in both associations are hemicriptophytes (50-
52.07%). In the association Polygono-Bidentetum tripartitae, in addition to
them there are therophytes (23.76), hydrophytes (9.8), geophytes (9.80) and
with a very small participation chamaephytes and phanerophytes. In the
association Xanthieto riparii-Chenopodietum rubri therophytes are slightly
more frequent (40%), while the participation of hydrophytes and
chamaephytes is very small (5%) (Table 4, Figure 4).
7
s
0.3
0.29

Barudanovic and Kamberovic
Table 4. The average values of the life forms in the determined association
Life form (%) w H Ch G T Pn
Polygono-Bidentetum 9.80 52.07 3.03 9.80 23.76 1.51
tripartitae
Xanthieto riparii- 5 50 5 0 40 0
Chenopodietum rubri
(W- Hydrophytes, H- Hermcnptophytes, Ch- Chamaephytes, G- Geophytes, T- Therophytes,
Pn- Phanerophytes)
60
so
40
30
20
10
0
w H Ch G T Pn
• Polygono­
Bidentetum
tripartitae
• Xanthieto riparii­
Chenopodietum
rubri
Figure 4. The biological spectrum of the determined association
In areal spectrum most dominant floral elements were euroasian
(80.95-82.67% ). Mediterranean floral elements are more present in the
association Polygono-Bidentetum tripartitae (10.37% ), while elements of the
flora of North America are more present in the association Xanthieto riparii­
Chenopodietum rubri (Table 5, Figure 5).
Table 5. The average values of the floral element in the determined
association
Floral elements (%) Euroasian Boreal Mediterranean North
/association American
Polygono- 82.67 1.47 10.13 5.71
Bidentetum
tripartitae
Xanthieto riparii- 80.95 4.76 4.76 9.52
Chenopodietum
rubri
8

Weed vegetation on the shores of artificial reservoirs of surface mining pits in ...
• Polygono ­
Bidentetum
tripartitae
• Xanthieto riparii­
Chenopodietum
rubri
Figure 5. The areal types spectrum of the detemrlned association
Analysis of the sociability of plant species shows that the both
communities are dominated by plant species from the category of pioneer
elements of secondary successions (DC, Val: 2). Increased participation of
weed species (W, Val: +1) occurs in the community Xanthieto riparii­
Chenopodietum rubri, while in the community Polygono-Bidentetum
tripartitae this form with the associated plant species (G, Val: +4) occurs in
almost equal proportion. Other fonns are represented below frequency of
15% (Table 6, Figure 6).
Table 6. The social behavior types spectrum of the determined association
Social behavior types AC RC w DC G c s
(%)
Polygono - Bidentetum
tripartitae
8.8 5.9 15 44.11 17.64 5.88 2.94
Xanthieto riparii -
Chenopodietum rubri
9.1 14 32 36.36 9.09 0 0
.
(AC - mvauve spectes, RC - ruderal competitors. W - weed spectes, DC-ptoneer spectes of
secondary successi.ODs,
G- associated plant species, C - competitors, S-seDSitive species)
9

Barudanovic and Kamberovic
so .--------------
45 +-------------
40 +------- ------
35 +------'
30 +--------'
25 +--------'
20 +--------'
15 -1-----
10 -1-----___.
5
0
AC RC W DC G C S
• Polygono - Bidentetum
tripartitae
• Xanthieto riparii­
Chenopodietum rubri
Figure 6. The social behavior types spectrum of the detennined association
Discussion
Communities of the alliance Bidention tripartiti within the order
Bidentetalia tripartiti develop in wet and very nitrified soils (anthropogenic
fluvisols) and anthropogenic eugleys. These are the habitats to which the
flood water during late autumn and early spring brings huge amounts of
different nutrients, so the soil is more or less of basic reaction (Red!ic et al.
2009).
On the lake Suhodanj, in the narrow littoral strip, at the flat and
slightly sloping terrains which are regularly under the water in the spring,
there is a vegetation development of the community Polygono-Bidentetum
tripartitae. In addition to the characteristic species, especially in the summer
aspect, the community is built by Lycopus europaeus, Mentha pulegium and
Potentilla reptans. The community is dominated by hemicryptophytes and
therophytes, which corresponds with the survey results on this community at
the banks of river Vrbas by Topalic-Trivunovic (2005). Although the
percentage of therophytes participation is only 23.76%, to this life form
belong plants of large cover values. The high water level that is maintained
until the summer period and a short vegetation period make competitive
advantage for annual plants, which from year to year reconquer littoral
region. The community is dominated by pioneering elements of secondary
successions, weed and associated plant species. Under natural conditions, this
community has an important role in preserving the watersides from excessive
erosion. It also has the same function on the shores of lake Suhodanj, and
towards the land it transforms into prograding stages of osier-beds.
Vegetation of the alliance Chenopodion rubri has the optimum in
habitats that are under constant anthropogenic influence, so they developed in
10

Weed vegetation on the shores of artificial reservoirs of surface mining pits in ...
the vicinity of human settlements, along roads and similar habitats (Red.Zic et
al., 2009). Kiesslich et al. (2003) stated that the communities of the alliance
Chenopodietum rubri most commonly occur on sandy and gravelly
substratum, as is the case with the shores of Lake Sjerkovaca, where in the
wider littoral region develops the community Xanthieto riparii­
Chenopodietum rubri. Water level in this lake varies up to 1.5 meters during
the year, and the shores are rather steep (more than 30 °) and gravelly, which
results in drained ground. As part of this community, in three vegetation
seasons, were determined 21 species with domination of species Xanthium
riparium Itzigs. & Hertsch.
Analyzing communities of the order Bidentetalia tripartiti at two
lakes, we reach the conclusion that the site on Lake Sjerkovaca is more
nitrophilic and xerophilic compared to the sites on Lake Suhodanj.
Ecological index of humidity which indicates fresh soils, may be the result of
a large terrain slope which provides a more drained ground, while on lake
Suhodanj the shores have small slopes, and the vegetation in muddy shores
appears as a narrow strip around the lake. Within the community Xanthieto
riparii-Chenopodietum rubri is determined a much larger proportion of
weeds and invasive plant species. The analysis results of the plant life forms
spectrum match with the research of Kiesslich et al. (2003), where
participation of therophytes is higher in communities of the alliance
Chenopodietum rubri than in communities of the alliance Bidention tripartiti,
which indicates warmer habitat conditions.
The formation of small reservoirs, due to constant alteration of the
natural landscape and the motion of surface flows during surface
exploitation, is a continuous process. At that times a little or no attention is
paid to the planning of relief and the hydrological status of the newly formed
lakes. As a result lakes are created where weed communities occur instead of
vegetation of ponds and swamps, due to steep shores and large variations in
water levels. An example is Lake Sjerkovaca, where after 25 years, pioneer
weed communities still exist, and the process of natural progradation runs
very slow.
Conclusions
In littoral zone of the surveyed reservoirs were identified 42 plant
species within the two different communities: Polygono-Bidentetum
tripartitae (W. Koch 26) Lohm. 50 at lake Suhodanj and Xanthieto riparii­
Chenopodietum rubri Lohm et Walth. in Lohm 1950. at lake Sjerkovaca.
Based on the ecological analysis we conclude that littoral habitats
with weed vegetation of artificial reservoirs have a favorable light regime,
they are mesotherm, mesophilic, neutral and ocassionally rich in nutrients. At
11

Barudanovic and Kamberovic
the same time, habitats with vegetation of the community Xanthieto riparii­
Chenopodietum rubri Lohm et Walth. in Lohm 1950. at lake Sjerkovaca are
more nitrophilic and xerophilic in relation to vegetation of the community
Polygono-Bidentetum tripartitae (W. Koch 26) Lohm. 50 at lake Suhodanj.
Phytogeographical analysis determined four floristic elements, and
the most prevalent in both communities are the species of wide distribution
(Eurasian and Central European floral elements).
The analysis of life forms of plant species showed dominance of
hemicryptophytes and therophytes. The analysis of sociability of plant
species, discovered that dominant were pioneering elements of secondary
successions, weed and associated plant species.
At the lake with a big terrain slope in littoral zone, and a high water
level variation, colonization is carried out by pioneer and weed species that
have existed there for numerous years. Bearing in mind that the age of lake is
25 years, great coverage of these species indicate a slow succession of
vegetation in littoral zone towards higher progradation stages. The
appearance of vegetation in muddy riverbanks at the surveyed lakes is a
consequence of variations in water levels and changing hydrological status of
newly formed lakes.
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13

Herbologia Vol. 12, No. 3, 2011
SEDUM SARMENTOSUM BUNGE (CRASSULACEAE), AN
ALLOCHTHONOUS SPECIES IN THE FLORA OF BOSNIA AND
HERZEGOVINA
Dubravka Soljan
Faculty of Science, the University of Sarajevo,
Zmaja od Bosne 33-35, 71 000 Sarajevo, Bosnia and Herzegovina, lsoljan@bih.net.ba
Abstract
Presence of the species Sedum sarmentosum Bunge in the territory of
Bosnia and Herzegovina was recorded for the first time in the area of
Sarajevo, and then published (Soljan, Abadzic & Muratovic, 2003),
representing a new piece of information for the allochthonous flora and flora
of the country in general. After the first locality was recognised, dispersion of
the species continued to be followed, so a series of new localities were found
in the area of Sarajevo (43°51'N, 18°23'E), but als:> elsewhere: in Jablanica
(43°39'N, l7°45'E), Donja Jablanica, and Konjic (44°32'N, 18°53'E).
The species S. sarmentosum exerts a great ability of adaptation to
extreme living conditions, it very easily propagates vegetatively, is dispersed
by animals and humans, so its further spatial expansion as a weed can be
expected, making threat to crops, but also to autochthonous flora in general.
Keywords: biodiversity of plants, habitat conditions, dispersion
Introduction
Most species of foreign origin (allochthonous species) in flora of
Bosnia and Herzegovina are those coming from the American and Asian
continents. One of them is Sedum sarmentosum Bunge, originating from
Eastern Asia; China and Japan (Riimpler, 1892, Siebert & Voss, 1896,
Foerster, 1956, Hess, Landolt & Hirzel, 1970 in Segulja & Bevilacqua,
1994), but Kitagawa, 1939 in Segulja & Bevilacqua, 1994) recorded
Manchuria, Korea and China. The species was introduced into North
America and Europe as a decorative plant, for its nice appearance during both
vegetative and generative phase (inflorescences are rich with tiny yellow
flowers and are long-lasting). In cultivation practice, it is used as
groundcover, and recently for green roofs in urban environment, which,
along with an aesthetic role, also have the role of a natural thermic insulator,
thus contributing to saving of heating energy in buildings (Werthman, 2007).

D. Soljan
However, this species frequently escapes cultivation and appears as half-wild
one.
The species Sedum sarmentosum shows a high tolerance to changes of
humidity and temperature of habitat. It well withstands both physiological
and physical drought. As a species escaped from cultivation, it inhabits
dilapidated anthropogenic habitats: asphalt crevices, road edges, walls,
flower beds etc. It is important to point out that the species does not show
tendency to live in a community with other plant species. Frequently it takes
an aggressive form.
The first data on the presence of S. sarmentosum in flora of Bosnia
and Herzegovina were published in an article by Soljan, Abad.Zic &
Muratovic (2003), being a new piece of information for the flora of BiH. The
species has been entered in the list of the invasive species in Bosnia and
Herzegovina (Redzic, Barudanovic & Radovic, 2008).
Material and methods
Observation of the species S. sarmentosum has been conducted in the
field over a longer period, where also a photo-documentation was made. A
lesser quantity of the collected plant material was preserved using the usual
technique of drying. As leaves of this plant are succulent, preservation of the
material by drying is slow and difficult. According to instructions for
preservation of succulents (Nikolic, 1976), part of the material was first
shortly boiled in water, hence killed, and then kept in a microwave oven for a
short time. Material treated in this way retained its natural colour and,
mostly, shape of the plant organs. Material kept in the Herbarium Collection
of the National Museum of Bosnia and Herzegovina was entered under the
inventory numbers 51409-514012.
Data obtained in the field have been completed with the data from the
literature sources.
Results and discussion
The species Sedum sarmentosum (Gold Moss, Graveyard Moss,
Stringy Stonecrop) is perennial, cushion-shaped, with numerous shorter and
longer, sterile and fertile, erect and creeping shoots (Lat. sarmentum- a twig
producing long, slender stems which take root along the ground).
Adventitious roots develop on most of nodules. Fleshy sitting leaves of
elliptic to narrowly lanceolate shape are bare, smooth-edged, with obtuse tip.
At their widest part they are approximately 5 mm of width, around 15 mm
16

Sedum sarmentosum Bunge (Crassulaceae), an allochthonous species in the ...
long, with three leaves in each whorl. The size of leaves decreases toward the
tip of a shoot (Fig. 1).
Upper stems bear rich inflorescences cymose, and each horizontal part
of an inflorescence bears several flowers. Diameter of flowers is a bit over 1
em. Petals (5) are yellow, and sepals (5) bright green and somewhat shorter
than petals. (Fig. 1 a, b). Flowering lasts around one month (May, June), and
plants are readily visited by insects (Fig. 1b).
It very efficiently propagates by vegetative way. Tiny parts of a shoot,
or only leaves, easily root in, which intentionally or unintentionally goes in
favour of anthropochory or zoochory. Efficient vegetative propagation of the
species contributes to its successful spatial dispersion.
The species S. sarmentosum is adapted to open habitats, very dry, but
also very humid; it does not demand specific type of soil nor aspect.
Individuals escaped from cultivation are most frequently found in habitats
made by human activity, such as asphalt crevices, edges and old walls,
neglected flowerbeds etc.; generally in habitats unsuitable for existence of
most other plants.
According to Segulja and Bevilacqua (1994), the species S.
sarmentosum was found in Croatia in Zagreb, Zabok, Stara Gradiska, Nova
Gradiska, and a series of other localities, so it has been entered into the Index
Florae Croaticae (Hrsak, 1997). In the adjacent country, Montenegro, the
species S. sarmentosum was also found in the city area of Podgorica
(Stesevic & Jovanovic, 2005, 2008; Hadziablahovic, 2010). In Serbia, the
third adjacent country, according to the Flora of Serbia (Gajic, 1972), this
species is not among 19 species of the Sedum genus. According to a
statement of Professor Dmitar Lakusic,this species is found as a wild one on
the Belgrade streets (2011), Fig. 2.
17

D. Soljan
Fig. 1. Sedum sarmentosum Bunge (Photo: D. Soljan)
a) Individual in flowering phase, b) Plants are frequently visited by insects,
c) The first noticed find in the crack of concrete parapet of a balcony,
d) The most recent find in the old part of the city (Begluci Street)
e) The species was found by the wall edges at the car park (Cobanija St.)
18

Sedum sannentosum Bunge (Crassulaceae), an allochthonous species in the .•.
,. •
Fig. 2. Distribution of Sedum sarmentosum Bunge species
A. Balkan region, B. Bosnia and Herzegovina,
according to data obtained from available sources
In the Flora of Bosnia and Herzegovina and Novopazarski Sand.Zak
(Beck, 1903-1927), sixteen species of the Sedum genus are listed, but not S.
sarmentosum.
The first encounter with this species the author of the paper had in the
spring 1991 in the city of Sarajevo, in the Grbavica residential quarter. The
plant was noticed at the outer part of balcony of a building, spontaneously
inhabiting a crack in the concrete parapet of the balcony (Fig.lc), as well as
by the building in asphalt crevices, and also on the roof of a neighbouring
garage. Supposedly, the plant was grown as a decorative one, and thanks to a
great ability of vegetative propagation of just one part that accidentally
reached out the flowerbed, it succeeded in inhabiting and growing out of the
space intended by the breeder. The plant was firsdy noticed in vegetative
phase, and then in flowering phase in May. After the war, in 1996, when this
part of the city was again accessible, the presence of this species was again
noticed at the same locality, but on a larger area.
During the fieldwork in the area of Sarajevo, several years after the
first recording of the species S. sarmentosum, discovery of a series of other
localities in the city has followed. In the central part of the city, the species
was found in asphalt crevices and by the wall edges at the car park in
tobanija Street (Fig. le), then on the roof of a garage near the medical centre
"Stari grad". The roof was completely overgrown with the plant. It was also
noticed in the streets Pehlivanusa and Cazim Catic. The plant was noticed at
the edge of a concrete balcony parapet in the Hiseta Street, in the flowerbed
near the building of the Science Faculty, near the building of the Emergency
Medical Centre; and this year it was noticed in the old part of the city, on its
northern slopes, in the Begluci Street (Fig. ld).
Outside Sarajevo, the species S. sarmentosum has so far been
registered only in Herzegovina. First, it was noticed near the restaurant
19
B

D. Soljan
"Zdrava voda" near J ablanica, close to a small artificial waterfall; then in
Donja Jablanica and in Konjic, at the city exit, near the OMV petrol station.
Considering the above mentioned localities of S. sarmentosum, it can
be concluded that the species is bound to urban environment, what is
corroborated by data of previously quoted authors. Therefore, it can be
expected that the species is likely to be also found in other cities of Bosnia
and Herzegovina, but a further field research should be done.
Conclusions
After the first published record on the presence of the allochthonous
species Sedum sarmentosum Bunge in flora of Bosnia and Herzegovina
(Soljan, Abadzic & Muratovic, 2003), which was a new piece of information
for flora of BiH, search for other localities in Sarajevo and elsewhere has
continued.
In Sarajevo, the species was found in a series of localities in the
central old part of the city, but also in the new part. It is thought that some
individuals were firstly grown as decorative plants, but over the time have
escaped from cultivation and spread as wild ones. The number of populations
increases and successfully exists, showing no ability to mix with populations
of other plant species.
Outside Sarajevo, the species S. sarmentosum was registered m
Konjic, Donja Jablanica and above Jablanica.
Considering the S. sarmentosum' s great ability of adaptation to
extreme living conditions, and very successful vegetative propagation, the
species, like many other allochthonous species, represents a potential threat
for the autochthonous flora. Human negligence of the environment increases
a threat of escaping the species out of control and possibly becoming a weed.
This paper could be an initiative for further field researches, with the
aim of obtaining more complete data on the range of this species in Bosnia
and Herzegovina.
References
BECK, G. M. (1903-1927): Flora Bosne, Hercegovine i Novopazarskog Sandzaka, Bd. 1-2,
Sarajevo, Beograd.
FOERSTER, K. (1956): Der Steingarten der sieben Jahrzeiten. Neuman Verlag, p. 376,
Berlin-Dahlem.
GAm::, M. (1972): Crassulaceae. In Josifovic, M. (ed.) Flora SR Srbije, IV: 212-237,
Beograd.
HADZIABLAHOVIC, S. (2010). The vascular flora of Cemovsko polje (Montenegro).
Natura Montenegrina 9 (1): 7-143, Podgorica.
HESS, H. E., LANDOLT, E. & R. (1970): Flora der Ashweiz und angrenzender Gebiete. Bd.
2, p. 262, Basel, Stuttgart.
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Sedum sarmentosum Bunge (Crassulaceae), an allochthonous species in the ...
HRSAK, V. (1997): Crassulaceae. In Nikolic, T. (ed.) Flora Croaticae - Index Florae
Croaticae. Nat. Croat. Vol. 6, Suppl. 1, Pars 2: 46, Zagreb.
NIKOLIC, T. (1996): Herbarijski prirucnik. Skolska knjiga, Zagreb.
REDZIC, S., BARUDANOVIC, S. & RADOVIC, M., eds. (2008): Bosna i Hercegovina
zemlja raznolikosti. Federalno ministarstvo okoliSa i turizma, Sarajevo.
RUMPLER, TH. (1892): Die Sukkulenten. (Nach dem Tode des Verfassers
herausgegenben von Prof. Dr. K. Schumann), p. 51, Berlin.
SIEBERT, A. & VOSS, A. (1896): Wilmorin's Blumengiirtnerei, 3. Aufl. Bd. 2, p. 297,
Berlin.
STESEVIC, D. & JOVANOVIC, S. (2005): Contribution to the Knowledge of
Nonindigenous Species of Montenegro. In Terzic S. (ed.) Proceedings of theWorkshop
devoted to the 25th Annivesary of the Faculty of Sciences and Mathematics at
Universuty of Montenegro: Contemporary mathematics, fisics and biology -
University of Montenegro, 65-78.
STESEVIC, D. & JOVANOVIC, S. (2008): Flora of the city Podgorica (Taxonomic
analysis). Arch. Bioi. Sci. Belgrade. 60 (2), 245-253.
SEGULJA, N. & REGULA BEVILACQUA, U. (1994): Sedum sarmentosum Bunge a
newcomer in Croatien flora. Nat. Croat. Vol. 3, No 1: 91-97, Zagreb.
SOU AN, D., ABADZIC, S. & MURATOVIC, E. (2003): Neophytes in Flora of Bosnia and
Herzegovina. 3th International Balkan Botanical Congress, Abstracts: 197, Sarajevo.
WERTHMAN, CH. (2007): Green Roof" A Case Study. New York, NY: Princeton
Architectural Press.
21

Herbologia Vol. 12, No. 3, 2011
COMPARISON BETWEEN DIGITAL ANALYSIS METHODS FOR THE
ESTIMATION OF VEGETATION COVER IN WEED RESEARCH
G. Bocci, F. Bigongiali, P. Barberi, A.C. Moonen
Land Lab, Scuola Superiore Sant'Anna, Piazza Martiri della Liberta 33, 56127 Pisa,
Italy
E-mail: barberi@sssup.it
Abstract
Vegetation cover is a widely used parameter in weed research and
several methods are used to asses it through digital images, ranging from
simple methods (visual estimate) to more complex ones based on image
analysis processing. By using photographs of a wheat experiment we first
compared three simple subjective methods for the estimate of vegetation
cover through digital image analysis (visual estimate, point quadrate and
supervised classification) to understand which of them gave results which
were less dependent on operator's subjective value assignment. We did not
find a significant difference between operators in case of visual estimate
(P=0.784). We then tested the relative performance of two completely
automated image analysis techniques based on image transformations (IV 1 V 2
and Principal Components) frequently found in the scientific literature. IV 1 V 2
gave a better performance with respect to Principal Components. There was a
highly significant correlation (p=0.947) between IV1V2 and visual estimate,
i.e. the two methods of the respective categories which gave the best results.
Although being very simple and potentially influenced by operator's skills,
visual estimate always performed better in terms of repeatability. We
conclude that visual estimate carried out by experienced observers could be
regarded as a standard tool in weed research.
Keywords: crop cover, image analysis, point-quadrate method, visual estimate.
Introduction
Estimates of crop and weed cover are widely used in many
agricultural experiments: methods used to quantify plant cover include point
quadrate (Goodall, 1952; Cunningham, 1975), line intercept (Andrade and
Ocumpaugh, 1979) visual estimate (Cosser et al., 1997) and digital image
analysis (Zhou et al., 1998). Goodness of estimates provided by these
methods may vary greatly. Visual estimate is easy for operators to learn, it
does not require specific instruments and it is convenient when a large
number of plots must be assessed, but it can potentially be biased by factors
like fatigue, experience and skills of the operators, complexity of the

Bocci et al.
observations, knowledge of the expected treatment effect and lack of
standardised scales or methods that would improve the consistency of visual
ratings (Gnegy, 1991). Digital image analysis is gaining pace as a substitute
to visual estimate in crop protection research. To date, the scientific literature
has included the use of different image analysis processing techniques to
estimate crop soil cover after weed harrowing (Hansen et al., 2007;
Rasmussen et al., 2007) or ground cover of crop and weeds in competitive
ability studies (Cosser et al., 1997), to quantify herbicide efficacy (Lemieux
et al., 2003), to predict characteristics of crop canopy cover (Neeser et al.,
2000; Behrens and Diepenbrock, 2006) and to assess weed density
(Andreasen et al., 1997). The accuracy of the estimates depends on the image
processing procedure, which complicates comparison of data from different
experiments.
In experiments aimed to screen the weed suppression ability of wheat
(Triticum spp.) cultivars against weeds, one operator has often to visually
estimate wheat cover in hundreds of digital images: the objective of this
study was to identify an effective, accurate and repeatable quantitative
method for obtaining vegetation cover data from a stock of digital
photographs representing different winter wheat (Triticum aestivum L.)
cultivars. In particular we tested: (1) which of three operator-based digital
image analysis methods provided operator-independent cover estimates; (2)
whether or not two different automated image analysis processing techniques
gave similar results; (3) the possibility of using a completely automated
process instead of more time-consuming operator-based assessment
Materials and methods
Image acquisition and software
A total of 693 digital photographs were taken in 2005-2006 and 2006-
2007 at the Interdepartmental Centre for Agri-environmental Research "E.
Avanzi" (CIRAA) of the University of Pisa in a field experiment carried out
to compare the weed suppression ability of different winter wheat cultivars.
Plots of 0.25 m 2 plof 1 were photographed using a Nikon D70 digital camera
mounted on a tripod 1.20 m high centred above the plot. Image analyses
were performed using the GRASS GIS software (Grass Development Team,
2007).
Comparison between operators for subjective methods
Two operators were trained to use the following three techniques:
(a) Visual estimation of vegetation ground cover (VIS): the operator
estimates the value of vegetation cover observing the photo and using
reference pictures as guidelines (Ferrari et al., 1987).
24

Comparison between digital analysis methods for the estimation of vegetation ...
(b) Point-quadrate method (PQ): a digital grid of 100 nodes, created through
GRASS GIS, is superimposed upon the photo, then the operator counts
how many nodes are touched by vegetation, thus obtaining an estimate of
the total percent vegetation cover.
(c) Supervised classification (SC ): this method is based on a remote sensing
technique (Richards and Jia, 2006). The operator first decides in how
many classes the image is to be segmented and then chooses
representative pixels for each class. These pixels are used as 'training
data' from a classifier algorithm which, as a result, gives a completely
segmented image.
(d)
The operators were asked to apply these techniques to a sample of 55 photos.
Comparison between automated methods
We compared two automated image processing methods that rely on
image transformations to eliminate disturbance factors (El-Faki et al., 2000).
We chose two transformations: the W1V2, proposed by Steward and Tian
(1998), and the Principal Components transformation (hereafter called PC)
(Thorp and Tian (2004)). The first (IV1V2) involves a change in image
coordinates from the classical RGB system to another system (IV 1 V 2) where
the V 1 axis give a measure of redness or greenness, with green-dominated
pixels represented by positive coefficients. In the PC transformation, the
second PC band (PC2) is correlated to vegetation cover (Thorp and Tian,
2004).
Since we aimed to separate plant (green) parts from soil and residues, we
chose (as segmentation procedure) to fmd the V1 an PC2 values that best
separated soil and residues from plants.
To find these threshold values for V 1 and PC2, we adopted the following
procedure: we segmented images using different values of thresholds and
then confront these images with manually segmented versions of the same
images; the comparison was done using the kappa coefficient (Richards and
Jia, 2006) as a measure of goodness of classification: this coefficient is
proportional to the number of pixels which are correctly labelled with respect
to a reference image (in our case the manually segmented image).
The complete procedure, which was applied to 25 randomly chosen
photos, is made of the following steps:
(1) For each photo, a sub-plot of an area equal to 1/25th of that of the frame
was randomly chosen and plant covered areas were manually digitised.
Each sub-plot area was then subjected to IV 1 V 2 and PC transformations
25

Bocci et al.
to obtain V 1 and PC2 bands.
(2) For each IV 1 V 2 and PC2 image we obtained several binary images using
increasing values of the threshold (the initial values of the thresholds
were arbitrarily chosen after looking at some IV1V2 and PC pictures: we
guessed that the thresholds would lie between the values 0 and 50 for V 1
and between 80 and 198 for PC2 so we used values contained in these
these ranges for our analyses).
(3) Each binary image was confronted with the manually digitised picture to
obtain the kappa coefficient; we thus obtained a series of kappa values
for each of the 25 photo. For each level of the threshold, the mean of the
25 kappa values was calculated, then the threshold with the highest
mean-kappa was chosen as the best one. The same procedure was
performed for the both the IV1V2 and the PC images (an example of the
results of the whole procedure is shown in Graph. 1).
The kappa values obtained with the two optimal thresholds (for V 1 and PC2)
were confronted in a pairwise comparison in order to assess whether one
transformation (either IV1V2 or PC), systematically gives better results (ie
higher kappa values).
Comparison between the best subjective and the best automated methods
The best automated transformation was applied to the same photos which
were previously analysed with the subjective techniques. The image
transformation was applied to the whole image; subsequently, the optimal
threshold value was used to separate vegetation parts from soil, and percent
vegetation cover was compared with the corresponding value obtained by
automated techniques.
Statistical analysis
For all data, the conditions of normality and homoscedasticity were checked
with the Shapiro-Wilk and Levene tests respectively. Pairwise mean
comparisons were used to compare results obtained by the two operators for
each of the three subjective methods. And to confront the two sets of kappa
values obtained with the two thresholds. When the Shapiro-Wilk test
indicated normality, at test was used, otherwise a Wilcoxon signed-rank test
was used.
The best among the three subjective methods was compared with the best of
the two automated methods by means of a pairwise test on vegetation cover
values. Linear correlation analysis was used (a) to assess the percentage of
match between vegetation cover values estimated by the two operators for
each of the three subjective methods and (b) to compare vegetation cover
26

Comparison between digital analysis methods for the estimation of vegetation ...
values obtained with the best subjective method and the best automated
method. In the case of (a), parametric correlation (Pearson's r) was applied to
SC and PQ data series whereas non parametric correlation (Kendall's tau)
was applied to the VIS series. In the case of (b), for the subjective method we
used the mean value between the visual estimates given by the two operators
for each photo. All statistical analyses were performed with the R software
(R Development Core Team, 2008).
Results
Comparisons between operators for subjective methods
For all subjective methods, the correlation between percent vegetation
cover values estimated by the two operators on the same photo (Graph. 2)
was highly significant (P < 0.001), thus apparently indicating independence
of results upon operator when using the same method of digital image
analysis. However, a trend appeared when photos were processed with PQ
and SC: operator A tended to systematically assign lower vegetation cover
values than operator B in the case of PQ (Graph 2a), whereas the opposite
occurred in the case of SC (Graph 2b). In the case of VIS (Graph 2c), there
was no apparent trend towards under- or overestimation of values from the
same operator.
This difference among subjective methods was confirmed by the results of
pairwise tests, which showed a highly significant difference between
operators for SC (t test, P = 0.007) and PQ (t test, P < 0.001) but no
significant difference between operators for VIS (Wilcoxon test, P = 0.784).
This suggests that VIS is the only method of the three that actually provided
operator-independent estimates.
Comparisons between automated methods
For the IV 1 V 2 transformation, a V 1 threshold of 7 gave the highest kappa
value (0.78), while for the PC transformation the highest kappa (0.65) was
obtained with a PC2 threshold value of 131.
27

Comparison between digital analysis methods for the estimation of vegetation ...
used for locating the sampling area as it is digitalized by the operator, a small
variation in the digitising process of the frame margins may result in a shift in
the location of the grid. As suggested by Ewing and Horton (1999), repeated
measurements with different orientations of the grid could be implemented in
this method to avoid positional or directional biases.
From the analysis of IV1V2- and PC-transformed images we can
conclude that the first is more effective than the second. Anyway, use of this
method alone did not allow us to obtain results comparable to those obtained
with visual estimate, therefore the two methods are not exchangeable.
Automated image analysis methods are widely used for vegetation
cover estimation and some researchers are working on the improvement of
their efficacy and their implementation as standard methods in research and
practical on-farm applications. A possible follow-up of our work could be to
refme the procedures we used and to use them to build a user-friendly
software. An example of such a tool is the free web-based software produced
by Rasmussen et al. (2008).
Among all the papers which used digital image analysis to estimate
vegetation cover, only few included the comparison among different
techniques (Neeser et al., 2000; Vanha-Majamaa et al., 2000; Murphy and
Lodge, 2002; Li et al., 2005,). More work in this direction is needed to
acquire baseline information useful for the identification of suitable standard
methods for application in crop protection research.
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ZHOU, Q., ROBSON, M., PILESJO, P., 1998: On the ground estimation of vegetation cover
in Australian rangelands. Int. J. Remote Sens. 19, 1815-1820.
32

Herbologia Vol. 12, No. 3, 2011
COMPETITION OF WILD MUSTARD (SINAPIS ARVENSIS) IN WINTER
WHEAT
Ralitsa Nakova
Plant Protection Institute, 2230 Kostinbrod, Bulgaria
ralitsa n@abv.bg
Abstract
The effect of Sinapis arvensis on grain yield and its components of
winter wheat was studied. Field experiments were conducted at the Plant
Protection Institute in Kostinbrod, Bulgaria. The wheat was affected by
natural occurrence increasing densities (0, 3, 6, 9 plants m- 2 ) of S. arvensis.
Wheat density, height, spike length, number of grain spike- 1 , grain weight
spike-\ 1000-grain weight and grain yield were determined.
Results showed that between wheat and S. arvensis inter-specific
competition was established. The increase of weed density resulted in the
reduction of yield components and grain yield. Regression analysis of the
data indicated that all wheat studied parameters were negatively affected by
S. arvensis density. Grain yield losses of approximately by 30% in wheat
were caused by S. arvensis 9 plants m- 2 • The relationship between wild
mustard density and wheat grain yield and its components depended on weed
density. The coefficient of determination (R 2 ) increased in the order: wheat
density>grain weight spike- 1 >wheat spike length>number of grains per spike,
wheat height> 1000-grain weight> grain yield. Statistical regression models
may prove to have practical applications by predicting the loss from these
explanatory variables. In this concept the determination of damage thresholds
is a basic requirement for integrated weed management system.
Keywords: wheat, Sinapis arvensis, density, competition, grain yield, yield components,
regression models.
Introduction
Sinapis arvensis is one of the most prevalent weed species in winter
wheat fields of Bulgaria. The competitive effect of this weed on wheat has
not document in Bulgaria. In the contemporary investigation the effect of
weed density was studied in the broad leave weeds: Papaver rhoeas (Nakova,
2003a), Galium aparine_(Nakova, 2003b)), Lithospermum arvense (Nakova,
2003c), Chenopodium album (Mohajeri et al., 2003), Viola arvensis,
Delphinium consolida (Maneva, 2007), Tripleurosporum inodorum (lonescu,
2007), Iva xantofolia (Valkova, 2007) in Bulgaria. Authors found the effects
of increasing density on the wheat. In a competitive situation the density of
weeds is a major factor influencing growth, developments and yield of the

R. Nakova
wheat. An increase weed density decreased the level of wheat height, fresh
and dry weight, leaf area. The effects of vary density in the terms of the
wheat grain yield and its components it was established. The increase in
weed density resulted in the reduction in wheat growth and yield
components. The greatest number of spikes m- 2 , spike length, number of
grains spike- 1 , grain weight spike- 1 , 1000-grain weight and hectoliter grain
weight were recorded for wheat monoculture. These morphological
parameters decreased with increase in weed intensity. Wheat yield
components were considered as an index for effect of weed competition on
wheat grain yield.
Mennan (2003), Sajadian et al. (2010) carried out field experiments
on wheat at six different densities of S. arvensis ( 1,2, 4, 8, 16 and 32 plants
m- 2 ). The effects of various densities of the weed were calculated as yield
losses compared with control plots in percentage. The yield losses of 36.87%
were observed at density of 32 plants m- 2 • The economic thresholds of S.
arvensis were between 1.02-5.38 plants m- 2 • The study of Zivanovic-Katic et
al. (2004) showed that, wheat grain yield decrease caused by S. arvensis_was
highly significant compared to the weed-free control variants. For S. arvensis
at densities ( 0,2, 4, 8, 16 and 32 plants m- 2 ) it was established that he was
more competitive than wheat based on wheat biomass relative competitive
abilities (RCA) of 0.37 for wheat and wild mustard biomass RCA of 2.75 for
wild mustard. Wheat relative competitive intensity (RCI) showed reduction
in inter-specific competition with S. arvensis ( Mousavi et al., 2003).
Weed density has been used as an explanatory variable for forecast of
yield decrease in many regression models. Most regression models describe
crop yield loss from a given weed density (Cousens, 1985). The studies of
Stoimenova and Alexieva (2003) and Valkova and Maneva (2008) showed
predicting yield and morphological parameters loss using weed density data.
The objective of this study was to estimate competitive effects of S.
arvensis on wheat.
Material and methods
Wheat and S. arvensis field competition experiments were conducted
in 2008 and 2009 at the Plant Protection Institute in Kostinbrod. The soil type
was chemozem with loamy texture, pH=6.2 and 9.6% organic matter.
Experimental design were randomized blocks with four replicates. Plots size
was 5 m 2 (1 m wide x 5 m long). In both years wheat cv. Sadovo 1 was
grown in competition whit wild mustard. Four weed densities (0, 3, 6 and 9
plants m- 2 ) were formed after wheat emergence. Seeds of S. arvensis was not
planted as there were sufficient natural soil reserves of seed of this species.
The weeds were thinned manually in order to reach the required density. All
weeds were marked and all other weed species emerged later in the season
34

Competition of wild mustard (Sinapis arvensis) in winter wheat
weight was directly proportional to the weed density. Analysis of data
revealed that increasing proportion density of S. arvensis increased wheat
grain yield loss. Various yield reduction in wheat due to S. arvensis
competition have been reported in the literature. Wheat grain yield were
reduced in the presence of S. arvensis by only 0.74 t ha- 1 at 10% field
moisture capacity, in contrast 2.14 t ha- 1 yield reduction were observed at
70% field moisture capacity (Wright et al., 1999). Boz (1997) found that one
S. arvensis in 1 m 2 causes 3.63% yield losses. The effect of S. arvensis
density on growth and reproduction was predicted by the equation. The
coefficients of determinations (R 2 ) were very high, ranging from 0.86 to 0.97
The regression models were fitted to the some dates of studies
parameters. The regression lines show that at three weed densities, wheat
grain yield and its components losses increased with number of S. arvensis
plants per m- 2 • The regression models may have practical applications, such
as the prediction of damage thresholds for specific S. arvensis /wheat
competition.
The results of this study suggested that early season control of wild
mustard in wheat was inevitable to ensure elimination of the impact of season
long competition with S. arvensis on winter wheat. Thus, control measures
for this weed need to be implemental in the growing season to minimize
wheat yield loss.
References
BOZ, 0, (1997): Doktoral Tesi. Cukurova Universitetsi, Fen Belimleri Eustitusu, pp, 102.
COUSENS, R (1995): A simple model relating crop yield loss to weed and crop density.
Annals of Applied Biology, 107: 239-252.
IONESCU, N (2007): Influence of emergence time and density of Triphlurosporum
inodorum on winter wheat (Triticum aestivum) 1 E.W.R.S. Synposium,
Hamar, Norway ,pp:95.
MANEY A, S (2007):Doktoral thesis, Kostinbrod, pp: 170-172.
MOHAJERI, D; CHEREHLOO, Jet. al.,(2005): Multi-species competition effect of weeds
on wheat. 13th E.W.R.S. Symposium, Bari, Italy, on CD.
MOUSA VI, S; RAHIMIAN, H., et al., (2003): Analysis of competition between wild
mustard (Sinapis arvensis) and winter wheat (Triticum aestivum L.) by competition
indices. Journal of Agricultural sciences and natural resources, 10 (2): 135-146.
NAKOV A, R, (2003): Study of the competition between wheat and Papaver rhoeas. l'h
E.W.R.S. Mediterranean Symposium, Turkey :125-126.
NAKOV A, R, (2007): Investigation on competition between wheat and Galium
aparine,Plant Science,44: 217-221.
NAKOVA, R,(2010): A study of the competition between winter wheat and Litospermum
arvense, Plant Science, 47: 565-569.
SAJADIAN, S; S. POUR et al., (2010): Effect of competition between wild mustard (
Sinapis arvensis) and winter wheat on wild mustard canopy structure. Proceeding
of 3rd Iranian Weed Science Congress, Bbolsar, Iran, pp: 221-222.
SARIC, T. (1977). Ekologija korova. Poljoprivredni fakultet, Sarajevo
39

R. Nakova
STOIMENOV A, I; S. ALEXIEV A, (2003). Predicting yield loss due to invest-igation to
from weed flora using density data or weed dry biomass. 7th E.W.R.S.
Mediterranean Symposium, Turkey: 135-136.
V ALKOV A, M. (2007): Intra-specific competition within Iva xanthifolia. Plant Science, 44:
86-89.
V ALKOV A, M and S. MANEY A. (2008). Interactions between I Xanthifolia and other
weed species. Herbologia, 1: 11-20.
WRIGHT, K et al.(1999): Influence of soil moisture on competitive ability and seed
dormancy of Sinapis arvensis in sprint wheat. Weed Research, 39: 309-317.
ZADOKS, Jet al., (1974). A decimal code for the growth stage of cereals. Weed Research,
14: 415-421.
ZIV ANOVIC-KATIC, S; NIKOLIC, Fetal., (2004). Competitive relationship between some
weed species and wheat. Acta Herbologia, 13 (1): 155-160.
40

Herbologia Vol. 12, No. 3, 2011
ANTAGONISM AND SYNERGY BETWEEN EXTRACTS OF
Ulva lactuca L., Padina pavonica L. AND Corallina officinalis L.
AfefLadhari a, Sami Achour b' Faten Omezzine a, Asma Rinez a,
Maali Zakhama b, Rabiaa Haouala c*
aDepartment of Biology, Faculty of Sciences of Bizerte, Jarzouna 7021, Tunisia.
b Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir 5000,
cDepartment of Biological Sciences and Plant Protection, Higher Institute of Agronomy.
Chott Meriem, University of Sousse, 4042, Tunisia. (UR03AGR04).
*rabiahaouala@yahoo.fr
Abstract
This study highlights interaction between allelochemicals of Padina
pavonica (L), Ulva lactuca (L) and Corallina officinalis (L). Aqueous (30
g/1) and organic (3000 ppm) extracts were mixed to have ten mixtures with
different proportions. Extracts and their mixtures were tested on germination
and growth of wheat. Results indicate that allelochemicals could interact and
their activity could be strengthened or decreased, according to mixtures
proportions. Wheat seedlings growth was stimulated by mixtures with high
proportion of P. pavonica. This effect was lessened by addition of U. lactuca
and/or C. officinalis extracts. Ethanol extracts of P. pavonica and C.
officinals induced root growth reduction while U. lactuca ethanol extract
reinforced this reduction. For chloroform extracts, C. officinalis extract have
mitigated the stimulatory effect of U. lactuca or P. pavonica extracts,
resulting in an antagonism. Results are conclusive pushing to exploit the
possible synergy and/or antagonism between molecules with interest, highly
sought in sustainable development but produced in very limited quantities.
Keywords: mixture, synergy, antagonism, algae, extracts.
Introduction
Allelopathy is a complex interaction among plants including
stimulatory as well as inhibitory influence through biochemicals released into
the environment (Mallik and Williams, 2009). Recently, lnderjit and
Dakshini, (1995) gave an overview of allelopathic activities in aquatic
habitats with particular emphasis on algae. In aquatic ecosystems,
allelopathic inhibition of algae by macrophytes is one of the main research
fields in allelopathy (Qian et al., 2009). At the same time most macro-algae
in particular, have to release bioactive secondary metabolites interfering with
competitors in their vicinity (Gross et al., 2003). Changes in allelochemicals
activities by different factors were also considered. These effects were

Ladhari et al.
assigned to interactions between different substances, hence the active sites
of allelopathic compounds may be modified. This phenomenon may be
explained by a possible synergy or antagonism between molecules (Chung et
al., 2001). Hasler and Jones (1949) demonstrated that a macro-algae and
micro-algae have an antagonistic relationship in both natural and
experimental aquatic ecosystems. Also, Einhellig (1996), observed a
synergistic inhibitory effect of mixtures. According to Duke et al. (2000), a
combination of two or more allelopathic aqueous extracts can act
synergistically and cause more phytotoxic effect on weeds.
U. lactuca is a common species of macro-algae found in green tides
(Bhang and Kim, 2000). Although toxic properties are rarely associated with
the bloom-forming green macro-algae, there is increasing evidence that these
macro-algae do produce chemical defenses against herbivores (Van Alstyne
et al., 2001) and their extracts exhibits negative allelopathic effects on
harmful bloom-forming microalgae (Nan et al., 2008). Padina pavonica (L.),
a brown alga has studied for its carbohydrate, lipids, vitamins, mineral salts
and other active ingredients (Kamenarska et al., 2002). Its compounds
possess cytotoxic activity against KB cells (Ktari and Guyot, 1999).
Corallina officina/is, a red alga of Corallinales order (Tyler-Walters, 2006) is
related to many important reef species. It forms crusts, discoid holdfast with
erect, calcareous segmented and branched fronds, giving the alga a 'featherlike'
appearance (Latham, 2008). Its compounds possess Anti-protozoal, antimycobacterial
and cytotoxic potential (Allmendinger et al., 2010). Algal
extracts showed a distinct pattern of activity against diatoms (Lam et al.,
2008).
In the present study, allelopathic potentialities of three macro-algae:
Ulva lactuca L., Padina pavonica L. and Corallina officina/is L. were
evaluated. Then, in order to increase allelochemicals effects, mixtures of their
extracts with different proportions were tested on wheat, highlighting a
possible synergy or antagonism between allelochemicals.
Algal sample collection
Material and methods
Thalli of macro-algae (C. officina/is, P. pavonica and U. lactuca) were
collected from Tunisian littoral (Mahdia and Monastir) in July 2008. The
materials were carefully washed to remove attached organisms and debris.
42

Antagonism and synergy between extract of Ulva lactuca L., Padina pavonica ..
Aqueous and organic extracts
Fresh thalli of macro-algae were cleaned with tap water and were then
oven-dried at 60°C for 72 h and ground. Thirty grams of each dried materials
were soaked in 1000 ml of distilled water at room temperature for 24 h to
give a concentration of 30g/1 dry tissue (3% w/v) (Chon et al., 2005). The
extracts were filtered and kept at 4°C in the dark for further use.
Sequential extractions were carried out with two organic solvents with
rising polarity: chloroform and ethanol. Eighty grams of algal powder were
immersed in the organic solvent for 7 days at room temperature. Organic
extracts were evaporated to dryness under reduced pressure at 45-50°C, using
Rotavapour R-114. Dry fractions were stored at 4°C until use. The extracts
were tested at 3000ppm in bioassays.
Mixtures design
We tried to highlight a possible interaction between chemicals
substances included in the different extracts. We followed the mixture design
process using MINIT AB software that gives a limit number of mixtures but
can provide results for all possible proportions. Ten combinations provided
by this software and different proportions of these mixtures are presented in
Table 1.
Table 1. Different proportions of the three algal extracts (U.
Lactuca, P. Pavonica, C. officnallis) mixtures, given by MINITAB
software.
9 0.16667 0.66667 0.16667 1.00000
Essays U.lactuca P.pavonica C .officnallis Total
10 0.16667 0.16667 0.66667 1.00000
1 1.00000 0.00000 0.00000 1.00000
2 0.00000 1.00000 0.00000 1.00000
3 0.00000 0.00000 1.00000 1.00000
4 0.50000 0.50000 0.00000 1.00000
5 0.50000 0.00000 0.50000 1.00000
6 0.00000 0.50000 0.50000 1.00000
7 0.33333 0.33333 0.33333 1.00000
8 0.66667 0.16667 0.16667 1.00000
43

Petri dish bioassay
Ladhari et al.
Aqueous extracts and their mixtures were tested on Triticum aestivum
L. (wheat). Seeds were surface sterilized, imbibed in distilled water at 22°C
for 12 h and carefully blotted (Chon et al., 2005), and immediately sown in
Petri-plate bioassay. A filter paper disk was placed in each Petri dish and 5
ml of extract/mixture was pippetted per treatment, distilled water was the
control. Treatments were arranged in a completely randomized design with
three replications. Germination and shoot and root length of target species
were determined and expressed in percent of the control.
The two organic extracts, concentrated from chloroform and ethanol,
were dissolved in acetone. Two controls were considered, distilled water and
acetone to eliminate the possible effect of the latter. Filter paper placed in
Petri plates, were soaked with distilled water, acetone, organic extracts or
theirs mixtures, the solvent were evaporated for 15 min at 24°C. Mter that, 5
ml of distilled water were added and 20 soaked grains were put to germinate
for 7 days. Three replications were carried out. Germination and shoot and
root length of target species were determined and expressed in percent of the
control.
Results
Aqueous extracts and mixtures effect on wheat germination and growth
Aqueous extracts of P. pavonica, U. lactuca and C. o.fficinalis as well
as their mixtures did not affect significantly wheat germination, indeed
percentages germination were similar or slightly lower compared to the
control in all cases. The highest reduction (14%) was registered with U.
lactuca and P. pavonica extracts (Figure 1).
44

Ladhari et al.
Ethanol extracts of P. pavonica and C. officinals induced root growth
reduction by an average of 41%, U. lactuca ethanol extract reinforced this
reduction, suggesting a synergy between the different allelochemicals
extracted from the three algae by ethanol solvent.
Wheat shoots presented the same behavior in presence of ethanol
fractions and theirs mixtures (Figure 4B). Indeed, the most inhibitions were
registered in all cases and the maximum growth was obtained when mixtures
contained the highest proportions of P. pavonica ethanol extract (an average
growth 52.5% of control) or that of C. officina/is (a growth of over 55% of
control). Shoots growth inhibition (greater than 75%) was recorded especially
in presence of mixtures containing similar proportions of the three algae
ethanol extracts. The lowest length (24.6% of control) was recorded in
presence of mixture containing 0.56, 0.21 and 0.21% of U. lactuca, P.
pavonica and C. officina/is, respectively (Figure 4B). This result showed that
algae ethanol extracts contain bioactive molecules which inhibit growth of
wheat seedling. In addition, allelochemicals of the three algae may have
synergic effects, since their presence in similar proportions caused more
reduction of wheat seedling growth compared to the reduction registered in
presence of each extract tested alone (Figure 4).
In presence of chloroform fractions and theirs mixtures, root growth
was improved, when mixtures contained equal proportions of the three algae
chloroform extracts. Increasing of U. lactuca or P. pavonica extracts
proportion enhanced roots growth (root length more than 100% of the
control), while increasing of C. officina/is proportion, decreased the
stimulatory effect of the two other algae extracts. Indeed, inhibition reached
to 44% when mixture contained 97.9%, 1.2% and 0.8% of C. officina/is, U.
lactuca and P. pavonica chloroform extracts respectively (Figure 4C). This
indicates an antagonism effects between C. officina/is extract and the two
other algae extracts.
Wheat shoots response to mixtures of the three algae chloroform
extracts differed to that of roots. Indeed, the greatest lengths were obtained in
presence of mixture contained similar proportions between the three algae
extracts (Figure 4D).
48

Ladhari et al.
wheat shoots showed a greatest stimulation (8.45%) with a high proportion of
U. lactuca (47.98%) in mixture (Figure 4D).
Discussion
Results showed that wheat germination was similar or slightly lower
compared to control in presence of all aqueous extracts and their different
combinations. However, for growth and in all cases, effects of the three algae
extracts tested separately were different to their mixtures according to
extracts proportions. For some combinations, the effect of an extract has been
strengthened, for others it was reduced and became even contrary. Wheat root
growth was stimulated when mixture have a high proportion of P. Pavonica.
But C. officina/is extract, at high proportions, caused an inhibition of 55%.
This result suggests that P. pavonica and C. officina/is aqueous extracts had
an antagonism effect. Stimulation of wheat shoots was more important
compared to roots, especially in presence of mixtures with high proportions
of P. pavonica extract. Addition of U. lactuca and C. officina/is extracts
reduced the effect of P. pavonica extract. And gradually as C. officina/is
proportion increased, percentage stimulation was lower and shoots length
approached to the control. The improved of wheat seedling growth would be
ascribable to the presence of growth bio-active substances as trace elements,
phythohormones, amino acids, enzymes and vitamins released by P.
pavonica, U.lactuca and C.officinalis thalli. Similar results were reported by
Klarzynski et al. (2006) who recorded a stimulation growth of tomato and
wheat plants by filtrates of Ascophyllum nodosum (brown alga). In addition,
studies do not indicate the presence of toxic compounds in the alga. Norziah
and Ching (2000) showed that U. lactuca has high protein content, similar to
the content of plant proteins, such as legumes and cereals, especially soya.
Pak and Araya (1996) showed that this species is very rich in dietary fibber
with values much higher than that determined in fruits and vegetables, and
proteins including amino acids essential as the lysine, phenylalanine,
methionine, leucine and valine. Finally, a lipid content of 0.3 g/100 g dry
weight of this alga has been recorded by Ortriz et al. (2006). However a
conversion of these molecules into phyto-toxic products may be due to a
combination with other substances. Kamenarska et al. (2002) recorded that P.
pavonica was rich in sterol and lipid compounds which were significant
components of cellular membranes and responsible for a great number of
cellular functions. Moreover, P. pavonica contained a weak concentration of
toxic allelochemical compounds like terpenoids and phenolic acids
(Klarzynski et al., 2005). These compounds were known to have inhibiting
effects on germination and growth of various plants (Vyvyan, 2002). Thus,
the inhibition of wheat root/shoot growth could be enhanced by the release of
50

Antagonism and synergy between extract of Ulva lactuca L., Padina pavonica ..
allelochemicals of P. pavonica in extracts and their interaction with other
algal substances. Thus, effects of the three algae aqueous extracts tested
separately have been modified compared to those recorded in mixtures. These
results indicate that the chemical molecules could interact and their activity
could be strengthened instead be mitigated and even upset. Our findings are
in agreement with those of Jamil et al. (2009) who reported that mixture of
sorghum and sunflower aqueous extracts were more inhibitory for wild oat
and canary grass than sorghum aqueous extract alone. Allelopathic effects are
attributed to allelochemicals present in extracts, or to mixtures of
allelochemicals that have additive or synergistic activity (Einhellig, 1996;
Iqbal et al., 2004). Compounds in a mixture can replace each other on the
basis of their biological exchange rate and may add to the potency of each
other (Gerig and Blum, 1991). Einhellig (1996) observed an inhibitory
synergistic effect of mixtures allelopathic compounds. Mushtaq et al. (2010)
reported that mixture of allelopathic aqueous extracts were more effective
than sole sorghum aqueous extract.
These results were confirmed by testing mixtures of organic extracts.
For wheat germination, we registered a total inhibition only in presence of
mixture where the three ethanol extracts were in equal proportions. Wheat
growth was reduced in presence of ethanol extracts and we registered an
interaction between the three ethanol extracts which act synergistically.
Hence, ethanol extracts of P. pavonica and C. officinals induced root growth
reduction by an average of 41%, U. lactuca ethanol extract reinforced this
reduction. This result suggests a synergy between the different
allelochemicals extracted from the three algae by ethanol solvent. However,
an antagonism was detected for chloroform extracts, as increasing of U.
lactuca or P. pavonica extracts proportions enhanced roots growth, while
increasing of C. officinalis extract proportion decreased the stimulatory effect
of the two other. Indeed, inhibition reached to 44% when mixture contained
the maximum of C. officinalis extract. So, even if an extract appears to have
no effect, it could become active when it is mixed with other extracts.
Presence of stimulator compounds in algae extracts is reported in literature,
Hassan and Ghareib (2009) registered that U. lactuca acetone extract had
stimulatory effect on germination and growth of lettuce and tomato and such
stimulatory effect could be attributed to the possible synergistic effect
between the tested phenols as mentioned by Gerig and Blum (1991). In
others studies, Reigosa et al. (1999) and Hegab (2005) reported that, free
phenolic compounds (such as, vanillin) stimulated the germination and
seedling growth of different plants.
51

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54

Herbologia Vol. 12, No. 3, 2011
WEED CONTROL IN NEWLY SEEDED ALFALFA (MEDICAGO SATIVA
L.) WITH POSTEMERGENCE HERBICIDES
Zvonko Pacanoski
Faculty for Agricultural Sciences and Food, Skopje, R. Macedonia
E-mail: zvonkop@zf.ukim.edu.mk; zvonko lav@yahoo.com
Abstract
Field trials were conducted in 2008 and 2009 to evaluate weed control
in newly seeded alfalfa (Medicago sativa L.) with postemergence herbicides
and their influence on the alfalfa yield. The weed population in the both years
was consisted mainly of annual spring and summer weeds, and some winter
and perennial weeds. The weediness in the both years was relatively high.
Weed density in the untreated control plots was 170.3 plants per m 2 in 2008
and 148.5 plants per m 2 in 2009. The most dominant weeds in both years
were Echinochloa-crus galli, Chenopodium album, Anthemis cotula,
Polygonum convolvulus, and Linaria spuria. Efficacy of herbicides was
ranged from 94.0% (imazethapyr) to 97.5% (imazamox-1.2 L/ha) in 2008,
and 95.0% (imazethapyr) to 98.7% (imazamox-1.2 L/ha) in 2009,
respectively. Lower efficacy of bentazon due to domination of Echinochloa
crus-galli in the both years of field investigations. No visual alfalfa injured
were determined by any rates in both years, and consequently none of the
applied herbicides reduce first-harvest alfalfa yields. Herbicidal treatments in
both years significantly increase alfalfa hay yield in comparison with
untreated control.
Keywords: alfalfa, herbicides, weed control, alfalfa hay yield
Introduction
Sometimes referred to as the "Queen of Forages" (Miller and Ogg,
1995) alfalfa (Medicago sativa L.) is one of the most well known and widely
used forage crops in the world. Its high yield and quality allow it to be used
in feeding programs for many different types of livestock. As with any crop,
there are some abiotic and biotic factors contributing to the low alfalfa yield
and quality. Weeds are the most serious biotic constraint to higher yields,
competing for light, water, and nutrients (Wolfe and Southwood, 1980;
Cuturilo and Nikolic, 1986; Fischer et al., 1988; Kostov, 2006). Additionally,
weeds can change alfalfa forage composition and can have significant effects
on protein content and the overall quality of the feed ration (Cords, 1973;
Mueller and Fick, 1987; Undersander et al., 1993; Hallet al., 1995; Wilson,

Z. Pacanoski
1997). They can contribute over 80% of the total dry matter in the
establishment year (Moyer et al., 1995). Therefore, full expression of
alfalfa's productive potential and its long-term use depend on degrees of
weed infestation of its stands. Many authors (Cuturilo and Nikolic, 1986;
Gianessi et al., 2002; Cummings et al., 2004) consider the competitive
effects of weeds is the crucial among the factors infuencing the relatively
short exploitation period of an alfalfa stand.
Managing weeds is a critical component of alfalfa production (Ashigh
et al., 2009), particularly in the establishing year, because seedlings of alfalfa
are small, grow slowly, and are extremely susceptible to competitive
suppression by various weeds that germinate with the crop (Harvey, 1991;
Gianessi et al., 2002; Green et al., 2003; Zimdahl, 2004). Uncontrolled weed
growth in the seedling phase can result in complete alfalfa stand loss before
the first cutting (Anonymous, 1985; Cudney and Orloff, 1990).
Because of that, managing weeds in a timely manner is necessary to
provide maximum production of high yield and quality alfalfa hay (Canevari,
2001). To minimize weed problems requires an integrated approach which is
important in maintaining a weed free alfalfa stand. Controlling weeds
effectively begins well in advance of herbicide use. Herbicides are considered
as the most commonly used and reliable method for controlling weeds in
newly seeded alfalfa. The importance of their control has been emphasized
by various authors (Cudney and Orloff, 1990; Harvey, 1991; Tonks et al.,
1991; Darwent et al., 1997; Kostov and Pacanoski, 2006).
Taking into consideration necessity of chemical weed control for high
yield and quality alfalfa hay production, the objective of this study was to
investigate the effectiveness of some herbicides for controlling weeds in
newly seeded alfalfa, and, in same time, to estimate influence of herbicides
on the alfalfa yield.
Materials and methods
The field trials were conducted during 2008 and 2009 in the
Pelagonia region on a Molic-vertic gleysol cumuligleyic (Filipovski, 2006)
with 32.7% coarse, 47.3% fine sand, 19.9% clay+silt, 1.86% organic matter
and pH 6.0. The experimental design was a randomized complete block with
four replicates, and harvest plot size of 20 m 2 • The field trails were carried
out with alfalfa variety "Debarska" which was drill-seeded in a well-prepared
seedbed at a seeding rate of 18 kg/ha on April 8th, 2008 and April 15th, 2009.
Standard agronomic practices were followed during the both years of trails.
The following treatments were included in the study (Tab. 1):
56

Weed control in newly seeded alfalfa (Medicago sativa) with postemergence ..
Table 1. Trade names, active ingredients and rates of application of
herbicides
Treatment Active ingredient Common names Rate (L/ha)
(a.i.) giL
Untreated control
Imazamox 40 Pulsar-40 1.0
Imazamox 40 Pulsar-40 1.2
Imazethapyr 100 Pivot 100-E 1.0
Bentazon 480 Bentazon 480-EC 3.0
The herbicidal treatments were applied in the 3-4 trifoliate leaf stage
on May 19th, 2008, and May 22th, 2009, with a C0 2-pressurized backpack
sprayer with 350 L/ha water. Untreated control was included in the
studies. Weeds at the time of treatment were in the initial growth stages. Data
were recorded on the degree of weed density (by quantity method-number per
m 2 ), herbicidal efficacy, selectivity (by EWRS scale), and dry matter yield
(kg/ha).Weed control efficacy was estimated 28 days after treatment (DAT)
by the weed plants counting, and herbicide efficacy was calculated by
equitation (Mani et al., 1968):
where:
Wcp-Wtp
W CE = --------------- X 100
Wcp
W cE _ weed control efficiency
W cp- number of weeds in the control plots
Wtp- number of weeds in the treated plots
Alfalfa plant injury were rated 21 DAT. Visible injury ratings were
based on scale of EWRS (1 = 0% mortality and 9 = 100% mortality). The
alfalfa at both years was harvested three times, but only yield of the first
cutting is shown, because effects of applied herbicides were the most
significant in this harvest. First cut forage in the both years was harvested in
the middle to late of June, respectively when the alfalfa was in the early
bloom stage. Alfalfa yields were determined by mechanically harvesting
from 1m 2 of each plot, and the weight of the harvested samples were
recorded after drying at 50°C in a forced air oven. All yields are reported on a
57

Z. Pacanoski
dry weight basis. The data were subjected to statistical analysis applying
LSD-test (Steel and Torrie, 1980).
Results and discussion
Weed population: The weed population in the both years was
consisted mainly of annual spring and summer weeds, and some winter and
perennial weeds. In 2008 the weed population was consisted of 12 weed
species, and total number of weeds was 170.3 plants/m 2 (Tab. 2). The most
prevailinf among the 12 weed species were Echinochloa-crus galli (58.5
plants/m ), Chenopodium album (37.0 plants/m 2 ), Anthemis cotula (29.5
plants/m 2 ) and Polygonum covolvulus (21.3 plants/m 2 ). In the 2009 the
weediness was lower in compare with the previous year. Total number of
weeds was 148.5 plants/m 2 • The most prevailing among the 10 weed species
were Linaria spuria (42.5 plants/m 2 ), Echinochloa-crus galli (39.3 plants/m 2 )
and Polygonum convolvulus (28.5 plants/m 2 ).
Table. 2: Weed population (No/m 2 ) in the experiment (for both years)
Weed species
Echinochloa crus-galli (L.) P.B.
Chenopodium album L.
Anthemis cotula L.
Polygonum convolvulus L.
Linaria spuria Mill.
Solanum nigrum L.
Matricaria chamomilla L.
Amaranthus retroflexus L.
Xanthium strumarium L.
Lactuca scariola L.
Cirsium arvense (L.) Scop.
Sonchus asper (L.) Hill
Rumex acetosa L.
Artemisia vulgaris L.
Total weed species
Total weeds (No/m 2 )
2008
58.5
37.0
29.5
21.3
7.3
4.3
3.3
2.0
1.0
5.5
0.3
0.3
12
170.3
2009
39.3
12.5
16.3
28.5
42.5
0.3
1.3
0.3
7.0
0.5
10
148.5
Weed control and herbicide efficacy: Criterion for herbicide
efficacy was taken as the percentage of weeds that are control by any
particular treatment in compare with untreated control. Data regarding
herbicide efficacy presented in Table 3 show that all investigated herbicides
had a highly significant (P

Weed control in newly seeded alfalfa (Medicago sativa) with postemergence ..
years maximum weeds were recorded in untreated control plots (170.3 and
148.5, respectively). Minimum weeds in 2008 (4.3) were recorded in plots
treated with imazamox applied at higher rate (1.2 L/ha). Number of weeds in
plots treated with imazamox applied at lower rate (1.0 L/ha) were
insignificant higher in compare with imazethapyr (9.5 and 10.3,
respectively). In 2009, same as in previous year, minimum weeds (2.0) were
observed in plots treated with imazamox applied at higher rate (1.2 L /ha),
followed by imazamox applied at lower rate (1.0 L /ha) and imazethapyr (5.3
and 7.5, respectively). Number of weeds in plots treated with bentazon was
broad higher due to domination of Echinochloa crus-galli in the both years of
field investigations. Reduction of the weed density was in positive correlation
with herbicide efficacy, except of bentazon because it is active against
broadleaf weeds, only (Kostov, 2006). Efficacy of other herbicides was high,
and it was ranged of 94.0% (imazethapyr) to 97.5% (imazamox-1.2 L/ha) in
2008, and 95.0% (imazethapyr) to 98.7% (imazamox-1.2 L/ha) in 2009,
respectively (Tab. 3). Similar findings were reported by Dimitrova and
Milanova (2006), who stated that imazamox in combination with adjuvant
Desh applied in early growing season of alfalfa, birdsfoot trefoil and sainfoin
had high selectivity and herbicidal efficacy reaching 93-97% as compared to
the with weedy check.
Table 3: Effect of herbicidal treatments on weeds and herbicide efficacy
28 (DAT) in both years
Weed density Herbicide efficacy
per m-2 %
Treatments Rate
L/ha-
2008 2009 2008 2009
1
Untreated control 170.3 148.5
Imazamox 1.2 4.3** 2.0** 97.5 98.7
Imazamox 1.0 9.5** 5.3** 94.4 96.4
Imazethapyr 1.0 10.3** 7.5** 94.0 95.0
Bentazon 3.0 86.0** 55.3** 49.5 66.7
LSDO.OS 19.49 22.41
LSDO.Ol 27.32 31.42
(*) Significant level p

Weed control in newly seeded alfalfa (Medicago sativa) with postemergence ..
Bentazon 3.0 0.0 92.0 96.8 98.8 100.0
ECHCG- Echinochloa crus-galli; CHEAL-Chenopodium album; ANTCO-Anthemis cotula;
POCON-Polygonum convolvulus; LISPU-Linaria spuria
Visible alfalfa injury
Taking into consideration fact that all investigated herbicides applied
in properly alfalfa growth stages possesses high selectivity to alfalfa, no
visual injured were determined by any rates in both year, and consequently
none of the applied herbicides reduce first-harvest alfalfa yields (Tab. 5).
Similar results were obtained by Darwent et al. (1997); Tonks et al. (1991)
and Kostov and Pacanoski (2006). No visual injury was recorded in dry pea
when imazamox was applied at an earlier growth stage (Y enish and Eaton,
2002). Bentazon applied at 0.8 kg ai ha- 1 without an adjuvant caused an
average of 8% visual injury to newly seeded alfalfa, but did not reduce firstharvest
alfalfa yields (Harvey, 1991).
Dry matter yield (kg/ha)
The removal of the competitive effect of the weeds led in an increase
of the participation of the yield components of the alfalfa crop and as a result
the dry matter production also increased. Herbicidal treatments in both years
had significant (P

Z. Pacanoski
Table 5. First-harvest dry matter yields (kg!ha) and crop injury (average for both
years)
Treatments Rate
L/ha
Untreated control
Imazamox 1.2
Imazamox 1.0
Imazethapyr 1.0
Bentazon 3.0
LSD0.05
Dry matter yield (kg/ha) Alfalfa injury
(EWRS scale)
2008
1492
2855**
2797**
2742**
1666*
127.80
2009
1856
2668**
2685**
2573**
2022*
125.05
2008 2009
LSDO.Ol
179.18 175.33
(*)Significant level p

Weed control in newly seeded alfalfa (Medicago sativa) with postemergence ..
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64

Herbologia Vol. 12, No.3, 2011
EFFECT OF FORMASULFURON + ISOXADIFEN-ETHYL IN
COMBINATION WITH UREA ON MAIZE WEED CONTROL AND
YIELD
A. Tanveer, M.A. Nadeem, M.S. Quddus and F. Elahi
Department of Agronomy, University of Agriculture, Faisalabad, Pak:istan-38040
Corresponding author: Email:drasiftanveeruaf@hotmail.com
Abstract
A field experiment was conducted at Faisalabad, Pakistan, during
2004 and 2005 to study the effect of formasulfuron + isoxadifen-ethyl
applied alone and in combination with urea on weeds and yield of spring
(March-May) and autumn(August-October) maize (Zea mays L.). Six
treatments comprised of weedy check, manual hoeing, formasulfuron +
isoxadifen-ethyl 1125 g a.i. ha- 1 , 1125 g a.i. ha- 1 + 1% urea, 1125 g a.i. ha- 1 +
2% urea and 1125 g a.i. ha- 1 + 3% urea solution sprayed as post-emergence
(20 days after sowing) at four leave stage. Manual hoeing and formasulfuron
+ isoxadifen-ethyl 1125 g a.i. ha- 1 combined with 3% urea were the most
effective treatments for controlling Cyperus rotundus, Achyranthus aspera
and Trianthema portulacastrum. Maximum weed control efficiency with
formasulfuron + isoxadifen-ethyl1125 g a.i. ha- 1 combined with 3% urea was
87.0% for C.rotundus, 75.2% for A. aspera in spring maize. It was 82.0% for
C. rotundus and 90.0% for T. portulacastrum in autumn maize. The maize
yield from formasulfuron + isoxadifen-ethyl 1125 g a.i. ha- 1 + 3% urea
treated plots was 56% higher in spring and 68% higher in autumn than those
from weedy check and was comparable to that of manual weeding. Maximum
loss in grain yield in the weedy check control during spring and autumn
maize was 44 and 41%, respectively.
Keywords: formasulfuron + isoxadifen-ethyl, urea, weeds, maize, grain yield
Introduction
Maize is the third most important cereal grown in Pakistan after wheat
and rice. The average grain yield is 3.48 t ha- 1 (Anonymous, 2006). Among
the factors responsible for low yield, presence of weeds is considered to be
the important one. Weed interference in maize leads to 37 to 68% reduction
in crop yield (Adigun and Lagoke, 2003). Control of weeds is, therefore,
essential for obtaining good crop harvest. An increase of 31-33% in maize
grain yield has been reported with adequate weed control (Maina et al., 2001;
Chikoye et al., 2005). Mechanical methods of weed control are useful but are
getting expensive, laborious and time consuming. Moreover the labour

Tanveer et al.
availability for agricultural operations is becoming acute day by day and it
will not be possible and economical to stick the traditional practices. Keeping
in view these limitations, chemical weed control is an important alternative.
This method is quite effective if properly employed. Weed control efficiency
of 85-95% have been reported with herbicides in maize (Knezevic et al.,
2003; Alister and Kogan, 2005). Different types of pre and post-emergence
herbicides are used to control weeds in maize. Post-emergence herbicides are
generally absorbed through leaves. Leaf cuticle is composed of waxes and
cutin that affect the herbicide absorption. The use of adjuvant in combination
with herbicide enhances the herbicide retention on leaf surface and
penetration through the cuticle. Urea fertilizer is an effective adjuvant which
can be used along with herbicides for controlling weeds more effectively
(Getmanetz et al., 1991; Ssango and Balitenda, 2003; Singh and Singh, 2003
and Bunting et al., 2004). The present study, was conducted to determine the
effect of formasulfuron + isoxadifen-ethyl herbicide, applied alone and in
combination with urea on weeds and yield of maize under field conditions.
Materials and methods
The study was carried out at Agronomic Research Farm, University of
Agriculture, Faisalabad, Pakistan on a sandy clay loam soil. Six treatments
were studied namely weedy check; manual hoeing (2 hoeings);
formasulfuron + isoxadifen-ethyl 1125 g a.i. ha- 1 ; formasulfuron +
isoxadifen-ethyl 1125 g a.i. ha- 1 + 1% urea; formasulfuron + isoxadifen-ethyl
1125 g a.i. ha- 1 + 2% urea and formasulfuron + isoxadifen-ethyl 1125 g a.i.
ha- 1 + 3% urea solution. The experiment was laid out in a randomized
complete block design with four replications and a net plot size measuring 7
x 3 m. Maize variety "Golden" was sown as a test crop in August, 2004 and
March, 2005 with a single row hand drill using a seed rate of 35 kg ha- 1 in 75
em between rows. Plant to plant distance of 25 em was maintained by
thinning extra plants twice at an early growth stage. Fertilizers were applied
at the rate of 160 kg N ha- 1 and 80 kg P20s ha- 1 • Whole of the P and half of
the N were broadcast manually and incorporated into soil at seed-bed
preparation while remaining N was applied by broadcast method before
second irrigation. The herbicide was sprayed with a knapsack hand sprayer
fitted with flat fan nozzle with spray volume of water 300 L ha- 1 • This
amount was determined through calibration before spraying the herbicide.
Herbicide (mixed formulation) was dissolved after preparing 3% urea
solution in water. In all, five irrigations were applied to autumn and eight to
spring crop. Hoeing was done twice with the help of a hand hoe in the
respective treatment when soil was in proper moisture conditions after first
66

Effect of formasulfuron+isoxadifen-ethyl in combination with urea on maize ...
and second irrigation.
Weeds were counted from a unit area of one square meter at 15 and
25 days after spray at two places selected at random in each plot with the
help of a quadrate. Total dry weight of weeds was recorded by cutting at
ground level from a randomly selected area of one square meter at two
different places at maturity. After harvesting, weeds were cleaned. Weeds
were initially dried at room temperature and then in oven at 70°C for 72
hours. Ten cobs were taken randomly form each plot. Number of grains from
each cob was counted after shelling. To take 100-grain weight, five samples
each of 100-grains were taken randomly from bulk of plot yield weighed on
an automatic electronic balance. All the cobs from each plot were separated
manually and shelled with the help of a mechanical sheller and weighed to
record grain yield.
The data collected was analyzed statistically using Fisher's analysis of
variance. Least significant difference test was applied at 5% probability level
to compare treatment means (Steel et al., 1997).
Effect on weeds
Results and discussion
Weed flora at experimental site comprised of Achyranthus aspera,
Cyperus rotundus and Trianthema portulacastrum. Application of
formasulfuron + isoxadifen-ethyl alone and in combination with 1, 2 and 3%
urea solution significantly reduced the density of different weeds compared
with weedy check (Table1). In spring maize, formasulfuron + isoxadifenethyl
@ 1125 g a.i. ha- 1 + 3% urea solution performed better in controlling C.
rotundus after manual hoeing. In autumn maize, formasulfuron + isoxadifenethyl
@ 1125 g a.i. ha- 1 with 1 and 3% urea solution and manual hoeing were
at par with one another in respect of C. rotund us control.
As regards the control of broad leaves weeds i.e. A. aspera in spring
and T. portulacastrum in autumn maize, formasulfuron + isoxadifen-ethyl @
1125 g a.i. ha- 1 with 1, 2 and 3% urea solution and manual hoeing did not
differ statistically. Formasulfuron + isoxadifen-ethyl @ 1125 g a.i. ha- 1 with
various concentrations of urea significantly reduced the total dry weight of
weeds at harvest over weedy check. Formasulfuron + isoxadifen-ethyl with
3% urea solution performed better than other treatments.
In weedy check treatment undisturbed growth of weeds throughout
the crop life cycle resulted in maximum number of weeds and their dry
weight. It is thus evident that effectiveness of pre mixed formasulfuron +
isoxadifen-ethyl for weed control in maize can be enhanced by adding 3%
urea solution. Several works have reported better weed control with
67

Tanveer et al.
herbicides when used in combination with urea solution due to improved
penetration and enhanced phytotoxicity of herbicides( Borona et al., 2003;
Ssango and Balitenda, 2003; Singh and Singh, 2003; Bunting et al., 2004 ).
Table 1: Effect of formasulfuron + isoxadifen-ethyl alone and with urea on
weed density (No m- 2 ) and total dry weight (g m- 2 ) in maize
Spring maize Autumn maize
C. rotundus A. aspera TDM C. rotundus T. TDM
density density at density portulacasum at
harves density harves
t t
1S 2S 1S 2S 1S 2S 1S 2S
DAS DAS DA DA DAS DAS DAS DAS
s s
Weedy check 108.0 106.0 3.33 2.66 29S.90 29.2 10.7 143.0 172.0 138.9 a
Oa Oa a a a Sa Sa Oa Oa
Manual hoeing 14.00 4.66e 1.00 0.33 3S.04 f 8.00 7.SO 24.2S 32.2S SS.88 b
e b c b ab b b
Formasulfuron 42.33 34.67 1.66 1.33 104.20 s.oo 6.73 20.7S 22.SO 42.92 b
+ isoxadifen- b b b b b b ab b b
ethyl 1125 g
a.i. ha- 1
Formasulfuron 31.67 28.33 2.00 1.00 68.78 d 4.00 S.7S 27.7S 24.00 SS.7S b
+ isoxadifen- c be b be b b b b
ethyl 1125 g
a.i. ha- 1 + 1%
urea
Formasulfuron 28.67 24.00 2.00 1.00 77.21 c 4.2S 4.00 23.7S 26.75 49.67 b
+ isoxadifen- cd cd b be b b b b
ethyl 1125 g
a.i. ha- 1 + 2%
urea
Formasulfuron 21.33 19.00 1.33 0.66 41.78 e S.2S 4.50 19.SO 17.25 43.48 b
+ isoxadifen- de d b be b b b b
ethyl 1125 g
a.i. ha- 1 +3%
urea
LSD 9.029 7.837 1.13 0.87 4.974 9.141 4.96 16.623 21.40 17.92
5 8
Means sharing the same letter did not differ significantly at 5% level of probability.
Figures in parenthesis show weed control efficiency (%)
TDM=Total dry weight DAS = Days after sowing
68

Effect of formasulfuron+isoxadifen-ethyl in combination with urea on maize ...
Table 2: Effect of formasulfuron + isoxadifen-ethyl alone and with urea on
yield (t ha- 1 ) and yield components of maize
Spring maize Autumn maize
No. of No. of 100- Grain No. of No. of 100-grain Grain
cobs per grains grain yield cobs grins per weight yield
plant per cob weight per
plant
cob
Weedy check 1.00 281.00 e 21.636 2.31e 0.97b 488.5 b 22.08 c 3.35 b
Manual hoeing 1.06 480.00 a 24.87 a 4.12 a 1.12 ab 563.3 a 23.65 b 4.71 a
(98.35) (40.47)
Formasulfuron + 1.00 360.80b 24.19 a 2.88d 1.12 ab 606.5 a 23.85 ab 4.94a
isoxadifen-ethyl
@ 1125 g a.i.
ha-
(24.67) (47.24)
1
Formasulfuron + 1.00 351.70 c 24.94 a 2.98d 1.20 a 599.5 a 23.90 ab 5.00a
isoxadifen-ethyl
@ 1125 g a.i.
ha-
(29.00) (49.12)
1 + 1 urea
Formasulfuron + 1.06 313.00d 26.11 a 3.42c 1.20 a 592.5 a 24.10 ab 5.48 a
isoxadifen-ethyl
@ 1125 g a.i.
ha-
(48.05) (63.24)
1 + 2% urea
Formasulfuron + 1.06 362.20b 24.67 a 3.62 b 1.25 a 603.0 a 24.67 a 5.65 a
isoxadifen-ethyl
@ 1125 g a.i.
ha-
(56.70) (68.40)
1 +3% urea
LSD NS 6.676 2.362 0.152 0.172 44.28 0.979 0.956
..
Means shanng the same letters did not differ s1gmficantly at 5% level of probabllity
Figures in parentllesis show % increase over weedy check
Performance of maize
Formasulfuron + isoxadifen-ethyl alone and with various
concentrations of urea solution did not affect the number of cobs per plant
significantly in spring crop but effect was significant in autumn maize (Table
2). Application of formasulfuron + isoxadifen-ethyl alone and in combination
with 1, 2 and 3% urea solution significantly increased the number of grains
per cob and 100-grain weight over weedy check in both the seasons. There
was significant variation among different weed control treatments in respect
of number of grains per cob in spring crop but these treatments were
statistically similar in respect of 100-grain weight in spring and autumn
maize.
69

Effect of formasulfuron+isoxadifen-ethyl in combination with urea on maize ...
urea solution. Manual hoeing and formasulfuron + isoxadifen-ethyl alone and
with various concentrations of urea were statistically similar in respect of
maize grain yield in case of autumn maize.
Decrease in yield components of maize in weedy check was due to
unchecked growth of weeds, which competed with crop plants for different
environmental resources. On the other hand, efficient utilization of soil and
climatic resources by maize plants in the presence of relatively less number
of weeds in different weed control treatments led to increase in grain number
and weight (Shekhawat and Gautam, 2002).
Increase in grain yield due to different treatments over weedy check
was 24.7- 78.4% in spring and 40.5 - 68.4% in autumn maize. It might have
been due to increase in yield components of maize. Increase in grain yield of
maize as a result of better weed control with combined use of herbicide and
urea was reported by Ssango and Balitenda (2003) and Singh and Singh
(2003).
Conclusion
It can be concluded that formasulfuron + isoxadifen-ethyl 1125 g a.i.
ha- 1 +3% urea solution applied as post-emergence proved out to be the most
effective chemical weed control treatment to increase grain yield of maize _for
growing conditions of Pakistan.
References
ADIGUN, J.A. and S.T.O. LAGOKE, 2003: Comparison of some pre-emergence herbicide
mixtures for weed control in maize in the Nigerian Nothern Guinea Savanna.
Journal of Sustainable Agriculture and Environment, 5(1): 63-73.
ALISTER, C. and M. KOGAN, 2005: Efficacy of imidazolinone herbicides applied to
imidazolinone-resistant maize and their carryover effects on rotational crops.
Journal of Crop Protection, 24(4): 375-379.
ANONYMOUS, 2006: Economic Survey of Pakistan. Ministry of Food and Agricultural
Division (Planning unit), Government of Pakistan, Islamabad. pp. 25-27.
BORONA V., ZADOROZHNY V. AND T. POSTOLOVSKAY, 2003: The influence of
adjuvants on the effica;; of graminicides in soybeans and niconsulfuron in maize.
Proceedings of the 2 Weed Conference, Sarajevo, Bosnia and Herzogovina,
4(1):151-155.
BUNTING J.A., C.L. SPRAGUE AND D.E. RIECHERS, 2004: Proper adjuvant selection
for foramsulfuron activity. Journal of Crop Protection, 23(4):361-366.
CHIKOYE D., U.E. UDENSI AND A.F. LUM, 2005: Evaluation of a new formulation of
atrazine and metolachlor mixture for weed control in maize in Nigeria. Journal of
Crop Protection, 24(11):1016-1020.
GETMANETZ A.Y., S.M. KRAMAREV, V.P. VITTSENKO, B.A. BOVYKIN, N.S.
TISHKINA AND A.S.MATROSOV, 1991: Chemical compatibility of ZhKU 10-
34-0, KAS-28 and herbicides and their combined use in intensive maize growing
technology. Agrokhimiya, 11, 38-44.
KNEZEVIC M., M. DURKIC, I. KNEZEVIC, 0. ANTONIC AND S. JELASKA, 2003:
71

Tanveer et al.
Effects of soil tillage and post-emergence weed control on weed biomass and maize
yield. Cereal Research Communications, 31(1-2): 177-184.
MAINA J.M., E.G. THURANIRA, G.N. KIBATA, F.J. MUSEMBI, G. NYANYU, J.G.N.
MUTHAMIA, J.O. OKURO, I. MUTURA, S. AMBOGA, A.N. MICHENI, F.
MUREITHI, D. OVERFIELD AND P.J. TERRY, 2001: Participatory development
of weed management strategies in maize based cropping systems in Kenya. The­
BCPC-Conference, Proceedings of International conference Brighton, UK, pp.
199-204.
SHEKHAWAT P.S., AND R.C. GAUTAM, 2002: Effect of row spacing and weed control
methods on the growth attributes and grain yield of maize under tilled and untilled
conditions. Annals of Agricultural Research, 23(4): 626-629.
SINGH A.P AND P.C. SINGH, 2003: Effect of different weed control methods on growth
and yield of rabi-sown hybrid maize cv. Hybrid 4640. Journal of Living World,
10(2): 12-15.
SSANGO F. AND M. BALITENDA, 2003: Effect of application of which weed control
options on performance of two maize varieties in Uganda. Muarik Bulletin, No.6,
83-88.
STEEL R.G.D., J.H. TORRIE AND D.A. DICKY, 1997: Principles and Procedures of
Statistics A Biometrical Approach 3rd Ed. McGraw Hill Book International Co.,
Singapore. pp. 204-227.
72

Herbologia Vol. 12, No.3, 2011
SELECTIVITY OF SOME HERBICIDES TO CRESTED WHEATGRASS
(Agropyron cristatum (L.) Gaertn) GROWN FOR SEED PRODUCTION
Tsvetanka Dimitrova, Aneliya Katova
Institute of Forage Crops, 5800 Pleven, Bulgaria
E-mail: dimitrovatsvetanka@abv .bg
Abstract
During the 2008-2010 period, herbicides for perennial forage species
crested wheatgrass (Agropyron cristatum (L.) Gaertn), and their influence to
the seed productivity, were studied. As a result of the study it was found the
following: Herbicides for control of dicotyledonous weeds - Arat ( dikamba +
tritosulfuron) at the dose of 100 ml/ha, Korida 75 VDG (tribenuron) -15 g/ha
and Kambio SL (bentazon + dikamba) - 1250 ml/ha had high selectivity to
Agropyron cristatum (L.) Gaertn, applied at the stage of 2nd_4th leave during
establishing year of the stand and till the stage of the beginning of shooting
up in seed production year. The herbicide for controlling monocotyledonous
weeds Topik 080EK (clodinafop +adjuvant) at a dose 300 ml/ha, applied at
the same stages could be applied in seed production stands of A. cristatum.
The herbicide for the control of monocotyledonous weeds Grasp 25SK
(tralkoxydim) + atplus at the dose of 1000 + 1000 ml/ha shown phytotoxic
effect on A. cristatum and reduced seed production and dry biomass.
Keywords: crested wheatgrass (Agropyron cristatum (L.) Gaertn), herbicides, selectivity,
seeds, dry biomass
Introduction
Changes in climatic conditions during last years make it necessary to
study new grass species not typical for our grasslands. These species are
tolerant to high temperatures and insufficient water supplies in soil (Vasilev,
2005, Mannetje, 2006). This feature gives our attention to xerophytes from
the genus Agropyron, in which the crested wheatgrass (Agropyron cristatum
(L.) Gaertn) belongs to.
The studies for this species differ with good drought and cold
resistance are insufficient in Bulgaria (Yancheva, 1996; Chamov, 1998;
Stoeva, 2002). According to Vateva and Stoeva (2008) the successful
persistency of the wheatgrass was shown as good productivity. In studies of
Chakarov and Dimitrova (2003) was found that the crested wheatgrass can be
used successfully as the component of perennial double mixture with
sainfoin, birdsfoot trefoil and alfalfa and in triple mix with sainfoin and
birdsfoot trefoil with the aim to increase dry mass yield. Except for good

Dimitrova and Katova
forage qualities, the species posses good valuable agricultural characteristics
(Nastis, 1987; Lowrence and Ratzlaff, 1989; Leyshon and Campbell, 1992;
Chamov, 1998; Lingorski, 1999).
The first Bulgarian variety of wheatgrass Svejina is suitable for
establishment of pastures, stands to control soil erosion, and landscape
maintains. The variety was created in the Institute of Forage Crops - Pleven
(Katova et al.; 2010). The weed control in seed production is actual problem,
because of slow growth and development and low concurrence ability to
weeds, specially during the year of establishment (Dimitrova, 1984; Elgaard
and Nancen, 1988). Elimination of weeds competition ability during this
period is important feature for persistence and productivity of perennial grass
species (Dong et al., 2005). The long term treatment with the same active
ingredient is the main presumption for the herbicide resistance occurrence,
of course leading to changes in weed species composition. (Shkalikov, 1995;
Boger, 1997; Hain, 1997; Heap, 2009).
The limited studies concerning weed control and selectivity of some
herbicides to standard wheatgrass (A. desertorum) were conducted by
Dimitrova (2004, 2007), while the control with herbicides in crested
wheatgrass (A. cristatum) was not studied in Bulgaria up to now.
Serious problem of perennial grass seed production is weed control
with monocotyledons, because they belong to the same family Poaceae. The
Wild oat (Avena fatua L.) is economically important and broadly spread all
over the country. Its seeds coated with glumes and awns are difficult to
separate from the seeds of the cultivated crops. Except for that they mature
considerably earlier than the seeds of cultivated grasses, and part of weed
seeds germinate in autumn, but in large scale the weed infestation come on in
spnng.
Present demands with ecological and economical aspect need new
research for improvement of the methods and means to control the weeds.
The aim of the study was to determine which selective herbicides can
be used for crested wheatgrass and their influence to seed and dry biomass
productivity.
Materials and methods
During the 2008-2010 period in the experimental field of the Institute
of Forage Crops in Pleven, on slightly leached chernozem a study was
conducted. The experiment was established by the long plot method in three
replication with the size of the harvested plot of 5m 2 •
The subject of the study were post-emergent herbicides with systemic
activity, which were registered in Bulgaria for cereal crops. Concerning the
spectra of their action they control the weeds from the group of the annual
74

Dimitrova and Katova
herbicides for control of monocotyledonous weeds- Grasp 25SK and Topik
080EK. During the first seven days after treatment there were no phytotoxic
effect, while in 14DAT and 30-DAT for Grasp 25SK there were weak to
moderate (4 score), expressed as a weaker tillering of the plants. During the
first year the same effect was shown for Topik 080EK in lower degree (3
score), but in seed production year of the crop the higher resistance to the
herbicide was found and no phytotoxic effect observed. The behavior of
Grasp 25SK was different from that in seed production year, expressed in
weak delay of heading (3 score) in 14-DAT to moderate decrease of
generative stems (5 score).
Data in Table 3 conformed the observations by logarithmic scale of
EWRS for expressed influence of the herbicides on growth and development
of crested wheatgrass when harvested the growth for forage during
establishing year of the stand. It's seen that as the result of treatment with
herbicides for control of dicotyledonous weeds (V 2, V 3 and V 4) the values of
the characteristics number and fresh weight of vegetative stems from unite
area were close to these from untreated check (V 1). As a result of expressed
phytotoxicity of herbicides for control of monocotyledonous weeds (V s, V 6)
the deviations from these values were significant, lower with 13- 15% and
with 9-13%, respectively.
Table 1. Variants of the trial
Dose of Dosecommercial
active
Variants product ml ingredient
(g)/ha ml (g)/ha
V1 Check - untreated - -
V2 Arat (500 g/kg 100 75
dikamba+250 g/kg tritosulforon)
V3 Korida 75VDG (750 g/kg 15 11
tribenuron)
V4 Kambio SL (320 g/1 bentazon + 90 1250 513
g/1 dikamba)
V5 Grasp 25SK (250 g/1 tralkoxydim) 1000 + 1000 250 + 1000
+ atplus
V6 Topik 080EK (80 g/1 kodinafop + 300 24
adjuvant)
76

Selectivity of some herbicides to crested wheatgrass (Agropyron cristatum) ...
Table 2. Selectivity of herbicides to crested wheatgrass
Score of the damage (according to
Herbicide EWRS*)
Days after treatment
7 14 30
A B A B A B
Arat 1 1 1 1 1 1
Korida 75VDG 1 1 1 1 1 1
Kambio SL 1 1 1 1 1 1
Grasp 25SK 1 1 4 3 4 5
Topik080EK 1 1 3 1 3 1
*EWRS - Logaritmic scale (1-9) - score 1 -without damages; score 9 -crop is
completely destroyed
** A - during establishing year of the stand *** B - during seed
production years
Table 3. Influence of the herbicides to the growth and development of crested
wheatgrass during harvesting of 1st cut in the year of establishing of the
sward
Characters
Variants* Vegetative stems, Height of the Fresh weight of
numbers/m 2 stems, em the stems, g/m 2
v1 2250 27.3 1284
v2 2230 26.5 1256
v3 2247 27.5 1292
v4 2298 27.8 1301
Vs 1916 30.3 1112
v6 1950 30.5 1168
Average 2149 28.3 1236
min 1916 26.5 1112
max 2298 30.5 1301
77

Dimitrova and Katova
Table 4. Influence of the herbicides on seed productivity of crested
wheatgrass
Seed
Variant* 2009 2010 Average 2009-
2010
kg/ha %V1 kg/ha %V1 kg/ha %V1
v1 869 100 684 100 777 100
v2 862 99.2 674 98.5 768 98.8
v3 871 100.2 679 99.3 775 99.7
v4 858 98.7 677 99.0 768 98.8
Vs 645 74.2 564 82.5 605 77.9
v6 876 100.8 686 100.3 781 100.5
GDPs% 13.9 30.5 68.2
pl% 19.7 43.4 97.0
Po.l% 28.5 62.8 140.4
Table 5. Structural elements of the seed productivity of crested wheatgrass
Generative stems Length of the 1000 seed
Variant* number/m:t height, em ear, em weight, g
2009 2010 2009 2010 2009 2010 2009 2010
v1 2122 1634 75.7 76.6 6.9 6.3 1.98 1.74
v2 2108 1602 74.9 77.0 7.0 6.6 1.99 1.79
v3 2130 1614 75.5 76.9 6.7 6.8 1.96 1.77
v4 2100 1609 75.3 76.7 6.8 6.3 1.97 1.73
Vs 1580 1327 76.2 75.8 6.4 6.0 1.98 1.72
v6 2139 1629 76.0 76.4 7.0 6.2 1.99 1.74
Average 2030 1569 75.6 76.6 6.8 6.4 1.98 1.75
mm 1580 1327 74.9 75.8 6.4 6.0 1.96 1.72
max 2139 1634 76.2 77.0 7.0 6.8 1.99 1.79
78

Selectivity of some herbicides to crested wheatgrass (Agropyron cristatum) ...
Table 6. Dry biomass productivity of crested wheatgrass
Dry biomass
2008 2009 2010 Average
Variant* 2008/2010
Kg/ha %V1 Kg/ha %V1 Kg/ha %V1 Kg/ha %V1
v1 2860 100 10740 100 11270 100 8290 100
v2 2850 100 10830 101 11410 101 8360 101
v3 2950 103 10640 99 11350 101 8310 100
v4 2860 100 10810 101 11290 100 8320 100
Vs 2420 85 10860 101 10070 89 7780 94
v6 2500 87 10650 99 11360 101 8170 99
GDPs% 426.6 110.9 80.2 191.6
pl% 589.9 157.8 114.1 272.5
Po.l% 815.4 228.4 165.1 394.5
According the effect of herbicides on seed productivity of A.
cristatum it is seen that the tendency between variants during two years of
seed productions was kept (Table 4). The seed yield during the first harvest
year was within 645 to 876 kg/ha, and during the second harvest year- from
564 to 686 kg/ha. Significant deviation was seen for values of this character
for the stand treated with herbicide Grasp 25SK, which were with very good
negative evidence in comparison with untreated stand. Insignificant
differences for the seed yield from the stands, treated with herbicides for
control of dicotyledonous weeds (V 2, V 3, and V 4) and from these with
herbicide for control of monocotyledonous weeds Topik 080EK (V 6) was
evidence for their high selectivity to the crop. In conformation of this was the
fact there was not evidence of these differences.
From the data analyses shown in Table 5, the relationship was found
between the seed yield and elements of the productivity, which was the
strongest for the number of generative stems per unit area. During the year
with higher seed productivity their density in stands, treated with selective
herbicides was in margins between 2100 to 2139 numbers /m 2 , and during the
second seed harvest year from 1602 to 1634 numbers/m 2 . Formed generative
stems in experimental plot treated with Grasp 25SK (V 5) were significantly
lesser (from 1327 to 1580 number/m 2 ), because of expressed phytotoxicity.
For the stems height and length of the formed spikes the deviations for the
values were insignificant. With regard of the thousand - seed weight (TSW)
there was no regular trend in the different variants in the same year. However
there were some differences in the different years as follows: 1.96-1.99 g for
first harvest year and 1. 72-1.79 for the second one because of meteorological
conditins.
79

Dimitrova and Katova
From seed production stands of crested wheatgrass A. cristatum
significant quantity of additional production of dry biomass was obtained,
formed from crop residues and aftermath (Table 6). The formed yield from
the stands treated with selective herbicides was from 8170 to 8360 kg/ha,
average from the experimental. Again for this character was seen the negative
influence as the result of inhibiting effect of herbicide Grasp 25SK. This was
confirmed with a very good negative significance of the difference for the
yield.
Conclusions
The herbicides for control of dicotyledonous weeds - Arat ( dikamba +
tritosulfuron) at the dose of 100 ml/ha, Korida 75 VDG (tribenuron) -15 g/ha
and Kambio SL ( bentazon + dikamba)- 1250 ml/ha were highly selective to
Agropyron cristatum (L.) Gaertn, applied at the stage 2nd_4th leave during
establishing year of the stand and till the stage of the beginning of shooting
up in seed production year.
The herbicide for controlling monocotyledonous weeds Topik 080EK
(clodinafop + adjuvant) at a dose of 300 ml/ha, applied at the same stages
could be applied in seed production stands of A. cristatum.
The herbicide for controlling monocotyledonous weeds Grasp 25SK
(tralkoxydim) + atplus at the dose of 1000 + 1000 ml/ha shown phytotoxic
reaction to A. cristatum and reduced seed production and dry biomass.
References
V ATEV A, V., K. STOEVA, 2008: Analysis on vegetative performances in the productivity
of crested wheatgrass (Agropyron cristatum(L.) grown in the Balkans conditions.
Proceedings. Reports from Jubilee Scientific Conference "80 years Agricultural
Science in Rodopes mountain", Smoliyan, 25-26.09.2008: 171-175.
DIMITROVA, TS. 1984: Study on weeds and their control in seed production of perennial
legumes and grasses. PhD, Pleven.
DIMITROVA, TS. 2007: Study concerning the selectivity of some herbicides to standard
wheatgrass (Agropyron desertorum (Fisch. Schultes), cocksfoot (Dactylis glomerata
L.) and perennial ryegrass (Lolium perenne L.). Plant Sciences, 44: 162-166.
DIMITROVA, TS., R. CHAKAROV. 2004: Study on the weeds and their control in hayharvest
type of wheatgrass (Agropyron desertorum (Fisch. Schultes). Plant
Sciences, 41: 461-464.
KATOV A, A., P. TOMOV, Y. NAYDENOV A, A. ILIEV A. 2010: Official bulletin of the
Patent Office of The Republic of Bulgaria, N!!2/26.02.2010 r, p. 57.
LINGORSKI, V. 1999: Effect of mineral fertilization of crested wheatgrass (Agroryron
cristatum (L.) Gaertn.) in semi-mountain regions of Central North Bulgaria. Soil
Science, Agro-chemistry and Ecology, 34 (2-3): 65-68.
STOEV A, K., M. DIMITROV A - Doneva, 2002: Study of the possibility for growing of the
wheatgrass (Agroryron cristatum (L.) in pure stand and in herbal mixtures with
legumes. Proceedings of Dobrudja Agricultural Institute - G. Tochevo, volume.II:
621-625.
80

Selectivity of some herbicides to crested wheatgrass (Agropyron cristatum) ...
CHAKAROV, R., TS. DIMITROV A, 2003: Testing of crested wheatgrass (Agroryron
cristatum (L.) in mixtures with newly developed varieties of perennial legume
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81

Herbologia Vol. 12, No.3, 2011
USE OF SUNFLOWER RESIDUES IN COMBINATION WITH SUB­
RECOMMENDED DOSE OF HERBICIDES FOR WEEDS CONTROL IN
BARLEY FIELD
Ibrahim S. Alsaadawi and Ali A. AI-Temimi
Department of Biology, College of Science, Baghdad University, Baghdad, Iraq. Email:
ibrahimalsadwi@yahoo.com
Abstract
Sunflower residues at rates of 0, 600 and 1400 g per m 2 were
incorporated in field soil to evaluate their herbicidal potential alone and in
combination with 0, 50, 75 and 100% of recommended doses of 2,4-D and
Topic herbicides against weeds of barley crop. All treatments received equal
amounts of irrigation water and recommended doses of nitrogen and
phosphorus fertilizers. Combination of recommended dose of herbicides with
sunflower residues at 1400 g m- 2 produced minimum above-ground biomass
(122 g m- 2 ) and weeds number (155.5 weeds per m 2 ), which were 35 and
50% less than recommended herbicide dose applied alone, respectively.
Meanwhile, integration of herbicides and sunflower residue appeared
superior in enhancing yield per unit area than herbicide alone. Application of
50% dose of herbicides on plants growing in plots containing sunflower
residues at 1400 g m- 2 resulted in similar yield advantage as was noticed with
100% herbicide dose. Chromatographic analysis revealed the presence of
several phenolic compounds in the soil containing sunflower residues and
none of these appeared in soil without sunflower residues. Concentration of
total phenolic compounds appeared to be increased at two weeks of
decomposition, reached its maximum at the 4th week of decomposition and
started to decline thereafter until vanished at the 8th week of decomposition.
Weeds population started to increase after 6 weeks of residues decomposition
when the phytotoxins concentration was sharply reduced in the soil. The
possible advantage of this approach in reducing reliance on herbicides for
weeds control is briefly discussed.
Keywords: sunflower, allelopathy, herbicides, weeds, barley crop
Introduction
Weeds are one of the major problems that limit crop production in the
world through competition and allelopathy mechanisms (Rice, 1984; Singh et
al., 2001). Farmers are generally trending toward controlling of weeds with
herbicides which comes with increased awareness about health, environment
concern and other issues (Weston and Duke, 2003). Thus attention is focused

Alsaadawi and Temimi
on reducing reliance on using synthetic herbicides by finding alternative
strategy for weed management. Allelopathy can offer appropriate potential
tool for weed management by leaving residues of allelopathic crops in their
field alone or in combination with sub recommended dose of herbicides
(Cheema et al., 2003; Khaliq et al., 2002).
Sunflower allelopathy against weeds has been studied and well
documented by several investigators and appeared to be cultivar dependent
(Dahiya and Narwal, 2003; Naseem et al., 2009) In an earlier work
(Alsaadawi et al., 2011), it was found that root exudates and residues of
several sunflower genotypes caused substantial reduction to population and
biomass of companion weeds and weeds of wheat crop respectively.
Although the reduction was feasible and environment friendly, it was
generally less than herbicides. It may be possible to increase the efficacy of
sunflower residues by combining it with low rates of herbicides. Several
investigators have found that integration of water extract of allelopathic grain
sorghum with sub recommended doses of herbicides suppressed weeds
biomass as the recommended dose of herbicides (Cheema et al., 2003C;
Khaliq et al., 2002).
With this in minds, the present study was conducted to test
suppressive effect of sunflower residues in combination with sub
recommended doses of herbicides on weeds of barley crop.
Field study
Materials and methods
The experiment was conducted in a field heavy infested by weeds and
characterized by calcareous and loamy sand soil with pH 7.2 and electrical
conductivity 3.5 dS m- 1 • Plots (lx1 m) were selected randomly in field in
heavily infested with weeds in November 8. The plots were plowed by spade
to the depth of 30 em and received N as urea (46% N) at 200 kg/ ha and Pas
triple superphosphate (46% P20 5) at 200 kg ha- 1 • All phosphorus and half of
the nitrogen were applied at sowing time while the remaining half of nitrogen
was applied at tillering stage. The experiment comprised of sunflower
residue incorporated at rates of 0, 600 and 1400 g m- 2 and different doses (0,
50,75 and 100%) of2,4-D (72% a. i.) and Topic (10% a. i.) herbicides. 2,4-D
was applied at the 4th leaf stage to control broad leaves weeds while Topic
was sprayed two weeks after 2,4-D application to control narrow leaves
weeds. The doses of herbicides were applied using a Knapsack hand sprayer
fitted with T-Jet nozzle at a pressure of 207 k Pa. The treatments were used
either alone or in combination with each other. The rates of sunflower
residues were incorporated in the soil of their respective plots prior to
sowing. Seeds of barley cv. Samir were sown manually in the plots in rows
84

Use of sunflower residues in combination with sub-recommended dose of ...
with a distance of 20 em between rows and at seed rate of 120 kg/ha. The
experiment was conducted in split plot design with four replications for each
treatment. The herbicide rates were kept in the sub plot while sunflower
residue rates were assigned as main plot. The data were analyzed by analysis
of variance technique. The least significant differences test was used to
compare the means of treatments (Steel and Torrie, 1980).
At the end of crop maturity (May 5, 2010), weeds was counted in
each plot before and after herbicides application. Total weeds were clipped,
brought to laboratory, oven-dried at 70"C for 72 days and their weights were
recorded. For crop measurements, barley straw biomass (oven dry weight at
70"C for 48 h) and grain yield per m 2 were also recorded.
Isolation and quantification of phytotoxins in the decomposing sunflower
residues in soil:
Experiment set up of residues decomposition in soil and extraction of
phytotoxins:
Soil minus litters was taken from different sites of barley field. The
soil samples were mixed thoroughly and air dried under sun. Air dried shoots
of sunflower plants cv. Coupan were chopped into pieces of 2-3 em length
and incorporated in to the soil at a rate of 7 g/kg soil. The mixture was
packed in plastic pot of 10 kg capacity, irrigated with water to field capacity,
covered with perforated plastic cover to avoid evaporation and placed in the
field at the beginning of growing season of barley. Biweekly soil samples
were taken from the pot using metal soil borer and stored in deep freeze until
use.
For extraction of phenolic acids, the stored soil samples were taken
from the deep freeze and air dried mixed thoroughly. One gram of soil was
extracted with 100 ml of distilled water using a method of Harbome (1973).
The water extract was acidified with one milliliter of acetic acid. The mixture
was heated gently, mixed thoroughly by ultrasonic apparatus to exclude air
bubbles from the residues and allowed to stand for 4 h. The mixture of each
sample was filtered by filter paper under vacuum condition and kept in
refrigerator until use.
85

Alsaadawi and Temimi
Separation, identification and quantification ofphytotoxins
For identification, 50 pl of the extract was injected in Reversed Phase
Liquid Chromatogram (RVLC Shimadzu-C-6A) using procedure and
condition outlined by Hartley and Buchan (1979) and Alsaadawi et al.
(2011). The peaks were detected by UV detector. Standards of suspected
phytotoxins were run similarly for identification and quantification.
Concentration of each isolated compound was determined using standard
procedure.
Effects on weeds of barley crop
Results
Weed flora appeared in barley field comprised mainly of Avena fatua,
Melilotus indicus, Beta vugaris cicla and Centaurea bruguierana with other
minor species such Cynodon dactylon and Lolium rigidum. Both rates of
herbicides and sunflower residues caused significant reduction to total
number of these weeds (Table 1). Residues incorporation at 600 and 1400 g
m- 2 significantly suppressed weed density by 23 and 40% of control
respectively. The reduction in weeds density increased with the increased
rates of herbicides application. However, weeds density suppressed to greater
extent when herbicides applied in plots where sunflower residues were
incorporated. Herbicides and sunflower residues showed complementary
interaction and recorded 19 to 50% more suppression to weeds density than
recommended dose. Reduced herbicide dose (50%) in combination with
sunflower residue at 1400 g per m 2 scored weed suppression similar to that
realized with recommended dose used alone, while reduced dose (75%) in
combination with residues at 600 and 1400 g per m 2 suppressed weeds
density by 30% over the recommended dose of herbicide alone.
Weeds biomass was significantly inhibited by the herbicides and
sunflower residues treatments. The inhibition was significantly increased
with increasing rates of herbicide and residues incorporated into the soil
(Table 1). Recommended dose of herbicide when applied to plots amended
with sunflower residues at 1400 g m- 2 scored 2.85 times more weeds biomass
suppression than recommended herbicide dose used alone. Reduced
herbicides rates used in plots where sunflower residues were applied gave
even higher reduction in weed dry matter accumulation as compared with
plots where such doses were used alone. Use of 50% of recommended dose
of herbicide coupled with 1400 g m- 2 sunflower residues scored statistically
similar suppression of weeds biomass compared to that achieved with the
same herbicide dose applied alone. Treatment of 1400 g m- 2 sunflower
86

Use of sunflower residues in combination with sub-recommended dose of ...
residues + 75% of recommended dose of herbicides caused greater weed
biomass suppression than recommended dose of herbicide alone.
Table 1. Effects of different rates of herbicides (H) and residues (R) of
sunflower cv. Coupan on density and total biomass of weeds in barley field.
Herbicide rates
(% of recommended
doses)*
0 (Control)
50
75
100
Average
LSD =0.05
0 (Control)
50
75
100
Average
LSD =0.05
* See text for explanation.
Effects on barley crop
0
365.0
239.0
217.0
182.5
250.9
H= 13.7
1136.5
569.5
459.0
348.0
628.3
H = 69.1
Residues rates (g m- )
600 1400
Weed density
282.0 120.0
213.5 183.5
170.0 128.0
148.0 90.5
203.4 155.5
R=7.8 H X R= 21.4
Weed biomass (g m- 2 )
634.5 451.0
448.0 318.0
317.5 190.5
265.0 122.0
416.3 270.4
R= 92.3 HxR =129.3
Each number is an average of 4 replicates.
Average
289.0
212.0
171.7
140.3
740.7
445.2
322.3
245.0
Straw biomass and grain yield of barley were significantly affected by
treatments of herbicides and sunflower residues and their interaction (Table
2). Use of 50% of recommended dose of herbicides in combination with 1400
g m- 2 gave straw biomass similar to the recommended dose of herbicide alone
but increased number of tillers per plant by 37% over recommended dose
alone respectively, while the use of 75% of recommended dose of herbicides
accompanied with sunflower residues at 1400 g m- 2 increased straw biomass
by 22% over the recommended herbicide dose only.
87

Alsaadawi and Temimi
Combination of herbicide and sunflower residue at 1400 g m- 2 appeared
superior in enhancing yield per unit area than herbicide alone. Application of
50% dose of herbicides in plots amended with sunflower residue resulted in
statistically similar yield as was noticed at 100% herbicide dose. Maximum
yield (1045 g m- 2 ) was harvested from plots applied with recommended dose
of herbicides + sunflower residue at 1400 g m - 2 •
Table 2. Effects of different rates of herbicide (H) and residues (R) of
sunflower cv. Coupan on straw biomass and yield component of barley.
Herbicide rates Residues rates (g m- )
(% of recommended
doses) *
0 600 1400 Average
Straw biomass (g m- )
0 (Control)
50 167.5 199.0 223.5 196.7
75 212.3 232.5 284.8 243.2
100 233.0 274.3 330.0 279.1
Average 282.3 307.0 379.5 322.9
LSD=0.05 223.8 253.2 304.5
H=6.4 R=9.4 H xR= 12.5
Grain yield (g m- 2 )
O(Control) 88.4 109.5 123.8 107.2
50 107.9 172.4 179.3 153.2
75 137.1 194.0 241.6 190.9
100 182.6 204 .. 7 264.8 217.4
Average 129.0 170.2 202.4
LSD=0.05 H =19.2 R=22.4 HxR=34.2
* See text for explanation . Each number is an average of 4 replicates.
Phytotoxins isolation, identification and quantification
Chromatographic analysis revealed the presence of chlorogenic,
isochlorogenic, caffeic, gallic, syrinigic, hydroxyl benzoic, p-coumaric,
ferulic and vanillic acids in the residues of sunflower (Table 3). Catechol
was also observed. An appreciable amount of these phytotoxins was recorded
in residue incorporated soil. Hydroxy benzoic acid was found to be the
predominant constituent (6624 ppm) of residue decomposition products right
88

Use of sunflower residues in combination with sub-recommended dose of ...
from beginning. Considerable amounts of caffeic, gallic, syrinigic, ferulic
and vanillic acid were also observed. Dynamics of release, decomposition
and degradation of phytotoxins into the soil was quite interesting as different
phytotoxins showed differential behavior for these processes. Phytotoxins
released into the soil, increased with time and reached their peak values at 4
weeks after incorporation of residues. During this period, maximum
quantities of chlorogenic, isochlorogenic, caffeic, hydroxyl benzoic, ferulic
and vanillic acids as well as that of catechol were recorded. Afterwards, a
sharp decline in the quantities of these phytotoxins was observed at 6 weeks
that reached to almost negligible values at 8 weeks. Gallic and syrinigic acids
continued to increase up to 6 weeks and thereafter showed a decline. Pcoumaric
acid was maximum (522 ppm) at 2 weeks, and was not detected
after 4 weeks as did ferulic acid.
Table 3. Isolation, identification and quantification of phytotoxins of
decomposed sunflower residues m soil at different periods of
decomposition
Phenolic acids Concentration (PPM)
Decomposition periods (week)
0 2 4 6 8
Chlorogenic acid 93.23 48.86 76.23 37.46 0.59
Isochlorogenic acid 29.26 85.30 112.06 1.19 0.02
Caffeic acid 164.58 316.28 553.15 265.09 3.93
Gallic acid 126.23 349.16 58.73 665.07 0.26
Syrinigic acid 91.51 314.40 36.52 756.36 3.97
Hydroxy- benzoic 394.68 386.02 6624.27 179.55 5.46
acid
P- coumaric acid 110.95 521.77 13.41 0.00 0.00
Ferulic acid 84.59 311.50 41.69 0.00 0.00
Vanillic acid 120.33 342.40 94.35 238.52 13.4
Catechol 85.13 206.82 89.20 0.00 3.52
Total 1300.49 2882.15 9499.61 2143.24 1.37
*Average of two replicates
89

Alsaadawi and Temimi
Discussion
Results indicated that Incorporation of sunflower residues into the soil
caused substantial weed suppression. This suggests that sunflower residues
contain phytotoxic allelochemicals which may release during their
decomposition into the soil and affect the receiver species Rice, 1984).
Chromatographic analyses indicated that the residues contain several
phytotoxins of phenolic in nature (Table 3). These phytotoxins reached
maximum concentration 4 weeks after incorporation of residues in soil then
sharply declined at 6 weeks of decomposition in soil. The isolated
compounds proved to exert adverse effects on ion uptake (Putnam, 1990),
chlorophyll biosynthesis (Weir et al., 2004), cell membrane stability and
cellular metabolism (Bogatek et al., 2005; Keck and Hodges, 1973), protein
and hormone biosynthesis (Holappa and Blum, 1991, Rice, 1984), cell
division and ultra structural components of cells (Sanchez-Moreiras,
2004 ). Phytotoxic compounds other than phenolic acids have also been
isolated from sunflower residues (Macias et al., 2002). Some of these
compounds have been reported to have selective effects on broad leaved
weeds (Rice, 1984; Anjum and Bajwa, 2005). Most of these allelochemicals
are water soluble and when imbibed by the germinating weed seeds,
hampered their germination and subsequent seedling growth, thus
contributing to overall decline in the density, vigor and stand establishment
of the weed community (Gallandt et al., 1999).
It is interesting to mention that period indicating maximum quantities
of these phytotoxins (first 4 weeks) in soil coincided with the period in which
maximum suppressive activity against weeds was noticed in the field,
suggesting that these phytotoxins are probably the major cause of weed
suppression. After 5 weeks, weeds appeared to emerge and grow but could
not compete with barley plants efficiently. Dynamics of release of
phytotoxins revealed periodic rise in their level that eventually start declining
after 4 weeks. It seems that allelochemical release into rhizosphere through
residue decomposition is a function of time as well as concentration. Decline
in the levels of these phytotoxins is due to variety of physico-chemical and
biological transformations upon entering into the soil phase as proposed by
Blum et al. (1999).
Treatment of barley plants with 2,4-D and Topic significantly
suppressed weeds density and biomass. The suppression magnitude was
obvious at higher application rates than at lower rates i.e. 50 and 75 %of the
recommended dose. However, when herbicide application whether at low or
recommended dose was applied on plants grown in plots amended with
sunflower residues showed greater weeds biomass suppression than sole
application of herbicide was achieved (Table 2). Maximum weeds biomass
90

Use of sunflower residues in combination with sub-recommended dose of ...
suppression was obtained by integrating the recommended dose of herbicides
with sunflower residues at 1400 g m- 2 • Also, it seems that a reduced level of
herbicide (50% of recommended dose) may be feasible for providing weeds
control as the recommended dose of herbicides when it works simultaneously
with allelopathic conditions. It is possible that the residues inhibited seedling
growth and made them more susceptible to the even low level of herbicides.
The increase in growth and yield of barley crop by efficient control
treatments might be attributed to suppression of weeds in these treatments by
residues and thus eliminating the competition with wheat crop (Tables 1, 2).
Higher shoot biomass might be attributed to the greater availability of growth
factors to barley plants. Allelopathic crops including sunflower can be used
as potential means to control weeds and enhancing crop production using
different strategies such as using plant extract, plant residues as a cover and
mulch, crop rotation, crop mixture and inter cropping practices (Anjum and
Bajwa, 2005; Putnam, 1990; Dahiya and Narwal, 2003; Alsaadawi and
Dayan , 2009).
Thus it appears those sunflowers residues not only suppress weeds by
allelopathic and probably by smothering mechanisms but also improve
physical and biological characteristics and nutritional status of the soil. More
work needs to be done on other herbicides and crops and under
environmental conditions before defmite conclusion can be made. However
such approach would provide a useful tool for weeds control.
References
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in agroecosystems. Allelopathy Journal24: 255-270.
ALSAADA WI, I.S., SARBOOT, A.K. & L.M. AL-SHAMMAA, 2011. Differential
allelopathic potential of sunflower (Helianthus annuus L.) genotypes on weeds and
wheat (Triticum aestivum L.) crop. Archive of Agronomy and Soil Science (In
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ANJUM, T. & BAJAWI R. 2005. A bioactive annuionone from sunflower leaves.
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BLUM, U., ShAFER, S.R. & M.E. LEHMAN, 1999. Evidence for inhibitory allelopathic
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model. Crit Rev Plant Sci 18:673-693.
BOGATEK, R., GNIAZDOWSKA, A., STEPIEN, J. & E. KUPIDLOWSKA, 2005.
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CHEEMA, Z.A., FARID, M.S. & A. KHALIQ, 2003a. Efficacy of concentrated sorgaab in
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CHEEMA, Z.A., JAFFER, M. & KHALIQ, A. 2003c. Reducing isoproturon dose in
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GALLANDT, E.R., LIEBMAN, M. & D.R. HUGGINS, 1999. Improving soil quality:
implications for weed management. J Crop Production 2:95-121
HARBORNE, J.B. 1973. Phytochemical Methods: A guide to modern techniques of plant
analysis (2nd ed.). Chapman & Hall, London.
HARTLEY, R.D. & H. BUCHAN,1979. High performance liquid chromatography of
phenolic acids and aldehydes derived from plants or from decomposition of
organic matter in soil. Journal of Chromatography 180: 139-143.
KHALIQ, A., ASLAM, Z. & Z.A. CHEEMA, 2002. Efficacy of different weed management
strategies in mung bean (Vigna radiata L.). Int. J Agric Bioi. 4:237-239.
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by host- specific pathotoxins. Phytopathology 63: 226--230.
MACIAS, F., TORRES, A., GALINDO, J., VARELA, R., ALVAREZ, J. & J.
MOLINILLO, 2002. Bioactive terpenoids from sunflower leaves cv. Peredovick.
Phytochemistry 61: 687-692.
NASEEM, M, ASLAM, M., ANSAR, M. & M. AZHAR, 2009. Allelopathic effect of
sunflower water extract on weed control and wheat productivity. Pak J. Weed Sci.
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92

Herbologia Vol. 12, No.3, 2011
ALTERATIONS OF PHOSPHORUS METHABOLISM IN MAIZE
INBRED LINES INFLUENCED BY HERBICIDES
Vesna Dragicevitl*, Milena Simitl, Milan Brankov 2 , Igor Spasojevitl,
Branka Kresovitl
1 Maize Research Institute, Zemun Polje, Belgrade-Zemun, Serbia
2 Scholar of the Ministry of Science and Technological Development of the Republic of
Serbia
*E-mail: vdragicevic@mrizp.rs
Abstract
The presence of weeds complicates seed cropping, while the
herbicides could induce stress at inbred plants, dependently on genotype
sensitivity and agro-meteorological conditions. The phosphorus metabolism
in living organisms could be affected by different stress factors, including
herbicides. The aim of the experiment was to determine the influence of five
post-emergence herbicides (s-metolachlor + terbuthylazine + mesotrione,
topramezone, tembotrione + isoxadiphen-ethyl, nicosulfuron and
foramsulfuron + isoxadiphen-ethyl) on dry matter and different phosphorus
forms (inorganic and phytic phosphorus) 48 hours after their application in
seven ZP maize inbred lines, during 2008 and 2009.
Injurious effects of applied herbicides dependent on seasonal
influence: in 2008, as year with relative favourable condition during
sprouting phase, dry matter content was slightly decreased, together with
content of phytic phosphorus, which was followed by slight increase of
inorganic phosphorus, signifying possible damaging impact of applied
herbicides on phosphorus metabolism and biomass accumulation in maize
shoots, but in low degree. Meanwhile, during starting growth in 2009, most
of herbicides induced dry matter and inorganic phosphorus decrease, as well
as the increase of phytic phosphorus, compared to control, what was
particularly emphasized at foramsulfuron + isoxadiphen-ethyl treatment. The
negative influence of s-metolachlor + terbuthylazine + mesotrione was mainly
underlined during 2009, inducing dry matter and inorganic phosphorus
increase in all inbreds, affecting phytate biosynthesis and drying as one of the
most important signs of stress.
Keywords: maize, inbreed lines, herbicides, phytate, inorganic phosphorus

Dragicevic et al.
Introduction
Maize inbred lines are susceptible to various stress conditions. From
one hand, the presence of weeds in seed crop complicates activities that
should be performed on the optimum dates, as well as the maize grain yield
and from the other hand, herbicides could induce temporary or permanent
stress, dependently on genotype sensitivity and agro-meteorological
conditions. Temporary stress considers relative fast plant repairing, while the
permanent stress drives up different injures, such as plant drying, deprivation
and yield reduction (Stefanovic, et al., 2007; de Carvalho et al., 2009).
Climatic conditions are affecting in high extent faster or slower emergence,
growth and the development of maize and weed plants, contributing to better
of poorer efficiency of applied herbicides (Stefanovic et al., 2001; Stefanovic
et al., 2007; Stefanovic and Simic, 2008). The clear information about inbred
susceptibility is of a great significance planning of the hybrid maize seed
production.
One of the important mechanisms of herbicide action involves
production of reactive oxygen species in weed and also in crop plants
(Shaner, 2003; Luo et al., 2004). Meanwhile, the activity and production of
antioxidants is tied to herbicide tolerance: fast activation of detoxifying
mechanisms could diminish or shorten present stress, shifting its extent from
permanent to temporary stress.
The phosphorus metabolism in living organisms could be affected by
different stress factors. The phosphates absorption and metabolism could be
disturbed by different factors, including herbicides (Penner, 1970; Mishra
and Dubey, 2008). Meanwhile, the high level of phosphates could decrease
herbicide absorption by the roots, although they could have inhibitory effect
on root growth (Doll et al., 1970). One of the important points is phosphorus
storage pool - phytate, which also has protective role, acting as an
antioxidant in plants and animals (Graf et al., 1987; Doria et al., 2009), as
well as participating as precursor in ascorbate biosynthesis (Zhang et al.,
2008). Owing to these data, the phytate alternations could indicate lower or
higher stress tolerance in plants. Furthermore, the complexity of phosphorus
metabolism and its connection with oxidative attack is well described by
Gniazdowska et al. (1998), who underlined that prolonged phosphate
deficiency causes a decline in inorganic phosphorus concentration in bean
root tissues accompanied by a lower respiration rate via the cytochrome
pathway and increased alternative respiration using alternative oxidase.
The aim of the experiment was to determine the influence of five
post-emergence herbicides on dry matter and different phosphorus forms
(inorganic and phytic phosphorus), 48 hours after their application in seven
ZP maize inbred lines.
94

Alterations of phosphorus methabolism in maize inbred lines influenced by ...
Material and methods
The field experiment was conducted during 2008 and 2009 in the field
of the Maize Research Institute, in Zemun Polje on a slightly calcareous
chemozem soil type under rain-fed conditions. During the both experimental
years, winter wheat was used as a preceding crop.
The sowing was performed on 12 and 27 April, in 2008 and 2009,
respectively. Herbicides were applied at 4-6-leaf stage:. The main plots
encompassed one row of each inbred line, while subplots included herbicides
(Table 1) and a control without herbicide application. Effects of the herbicides'
application on the dry matter content, as well as phytic and inorganic
phosphorus content in seedlings of seven ZP maize inbred lines were
observed in the trial.
Table 1. Herbicide treatments
Treatm
ent
Applied herbicide (active
ingredients)
Trade
name
Dosage
T1
S-metolachlor + terbuthylazine +
mesotrione
Lumax
1500, 1500 and
150 g ha- 1 T2 Topramezone Clio
a.i.
67.2 g ha- 1 a.i.
Tembotrione + isoxadiphen-ethyl Laudis 88 and 44 g ha- 1
T3
a.L
T4 Nicosulfuron Motivell 50 g ha- 1 a.i.
T5
Foramsulfuron + isoxadiphen- Equip 45 and 45 g ha- 1
ethyl a.i.
Subsequently, the plant shoots were collected 48 hours after herbicide
application. The content of dry matter (DM) was determined after drying at
40°C. Phytic phosphorus (Pphy) was determined by the method of Latta and
Eskin (1980). Inorganic phosphorus (Pi) was determined from the same
extract colorimetrically, according to Pollman (1991).
The experimental data were statistically processed by analysis of the
variance (ANOVA) and analysed by the LSD-test at the 0.05 probability level.
Table 2. Average daily temperatures and precipitation sum during initial
growth, in seasons of 2008 and 2009
Temperature °C Precipitation mm
Month 2008 2009 2008 2009
IV
v
14.1
19.3
15.8
19.8
27.3
39.7
5.9
44.9
Average­
Sum
16.7 17.8 67 50.8
95

Dragicevic et al.
Meteorological data indicate that sprouting phase during 2008 was
characterized by lower temperature and higher precipitation level (Table 2),
while opposite trend was observed during 2009, with higher average
temperatures and lower precipitation.
Results and discussion
Generally, the all applied herbicides induced dry matter decrease in
both years (Table 3), what is in agreement with results of Wang (1997) who
also ascertained dry matter decrease in maize seedlings under the influence of
sulfonylurea herbicides. The obtained differences were under the limit of
significance in 2008, while in foramsulfuron + isoxadiphen-ethyl treatment
values approached to control. Among examined inbreds, only in L5 all of the
applied herbicides induced highest drop of average dry matter, in relation to
control. In 2009, as the season with higher average temperature and lower
precipitation level during starting growth (Table 2), the differences among
herbicide treatments and genotypes were significant (Table 3): s-metolachlor +
terbuthylazine + mesotrione induced dry matter increase in all inbreds,
indicating drying as one of the most important signs of stress (Stefanovic et
al., 2001, 2010), while the other herbicides induced dry matter decrease. The
highest dry matter decrease, influenced by herbicides was observed at L5 and
L7, among all genotypes. Obtained results of high dry matter accumulation
induced by s-metolachlor + terbuthylazine + mesotrione are supporting
statement that environmental factors, such as high temperature and lower
precipitation level could directly or indirectly affect absorption of herbicide
and its effect on plants (Janjic, 2002, Stefanovic et al., 2010), contributing
also to an expression of higher toxicity, as a consequence.
The noticed, but insignificant variations of phytic and inorganic
phosphorus in maize leaves among all treatments and genotypes during 2008
(Figure 1) were in agreement with insignificant variations of dry matter
values (Table 3), indicating relative weak influence of applied herbicides on
stress introduction, as well as biomass accumulation (Sacala et al., 2003).
The applied herbicides induced inconsiderable decrease of phytic
phosphorus, on average, in relation to control at most inbreds, but in higher
degree at L4, L5 and L6 (about 8-9%). At majority of genotypes, smetolachlor
+ terbuthylazine + mesotrione; topramezone and tembotrione +
isoxadiphen-ethyl decreased concentration of phytic phosphorus, what could
be connected to a positive role of phytate in stress tolerance, owing to its
antioxidative properties (Graf et al., 1987; Doria et al., 2009).
96

Alterations of phosphorus methabolism in maize inbred lines influenced by ...
Table 3. The dry matter content(%) of maize shoots collected 48 h after
herbicide application)
2008
Treat. L1 L2 L3 L4 L5 L6 L7 Average
T1 12.74 11.92 12.52 12.53 10.89 12.28 13.07 12.28
T2 13.67 12.36 13.15 13.72 10.96 12.53 12.91 12.76
T3 12.70 11.02 11.55 11.40 11.45 13.04 13.22 12.05
T4 13.80 13.15 14.21 12.88 11.01 13.46 14.08 13.23
T5 13.85 13.54 13.76 13.68 11.69 13.67 14.04 13.46
Average 13.35 12.40 13.04 12.84 11.20 13.00 13.46 12.76
Control 14.39 13.47 13.26 12.98 12.60 13.99 13.64 13.48
LSD Treatment: 3.57 Genotype: 5.17
5%
2009
T1 20.93 19.15 16.98 17.58 14.76 21.76 20.17 18.76
T2 12.29 11.53 12.13 10.02 11.04 11.38 11.80 11.46
T3 12.59 11.23 10.62 9.73 11.10 10.55 12.14 11.14
T4 12.96 11.19 12.72 10.78 11.00 12.41 12.33 11.91
T5 12.47 12.31 11.39 10.88 10.62 10.85 12.14 11.52
Average 14.25 13.08 12.77 11.80 11.71 13.39 13.71 12.96
Control 17.61 17.39 17.21 16.11 18.50 16.06 18.75 17.38
LSD Treatment: 0.48 Genotype: 0.42
5%
(Ll-L7 - mruze mbreds; Tl- s-metolachlor + terbuthylazme + mesotrione, T2 -
topr8.lllezone, T3 - tembotrione + isoxadiphen-ethyl, T4 - nicosulfuron and TS -
for8.lllsulfuron + isoxadiphen-ethyl
Meanwhile, the drop of phytic phosphorus was followed by
insignificant increase of inorganic phosphorus (Figure 1), indicating that
applied herbicides in some degree are affecting phosphorus metabolism in
maize shoots. Noticed results could be confirmed by investigations of Penner
(1970) who ascertained inhibitory influence of herbicides on phytase, enzyme
which participates in phytate metabolism. This situation was underlined at smetolachlor
+ terbuthylazine + mesotrione treatment, where higher
concentrations of both: phytic and inorganic phosphorus were observed,
indicating presence of oxidative stress which could increase requirement for
additional phosphorus for biosynthetic processes (Juszczuk et al., 2001).
Obtained data are similar to results of Ormrod and Williams (1960), who
observed increase of acid soluble organic phosphorus (which is majority
consists ofphytate), with increase of 2,4-D dose at Trifolium hirtum All.
The unfavourable meteorological conditions present during 2009
(Table 2) affected changes of phytic and inorganic phosphorus, too. Beside
97

Dragicevic et al.
with content of phytic phosphorus, which was followed by slight increase of
inorganic phosphorus, signifying possible damaging impact of applied
herbicides on phosphorus metabolism and biomass accumulation in maize
shoots in low degree. Meanwhile, during starting growth in 2009, most of
applied herbicides induced dry matter and inorganic phosphorus decrease, as
well as the increase of phytic phosphorus, compared to control, what was
particularly emphasized at foramsulfuron + isoxadiphen-ethyl treatment. The
negative influence of s-metolachlor + terbuthylazine + mesotrione was
particularly underlined during 2009, inducing dry matter and inorganic
phosphorus increase in all inbreds, affecting phytate biosynthesis and drying
as one of the most important signs of stress. Obtained results are underlining
antioxidative role of phytate, as well as possible inconveniences during its
biosynthesis influenced by herbicides.
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DOLL, J.D., D. PENNER, W.F. MEGGITT, 1970: Herbicide and phosphorus influence on
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DORIA, E., L. GALLESCHI, L. CALUCCI, C. PINZINO, R. PILU, E. CASSANI, E.
NIELSEN, 2009: Phytic acid prevents oxidative stress in seeds: evidence from a
maize (Zea mays L.) low phytic acid mutant. Journal of Experimental Botany, 3,
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MISHRA, S., R.S. DUBEY, 2008: Changes in phosphate content and phosphatase activities
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ORMROD, D.P., W.A. WILLIAMS, 1960: Phosphorus metabolism of Trifolium hirtum All.
as affected by 2,4-dichlorophenoxyacetic acid and gibberellic acid. Plant
Physiology 35, 81-87
PENNER, D. 1970: Herbicide and inorganic phosphate influence on phytase in seedlings.
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SACALA, E., A. DEMCZUK, T. MICHALSKI, 2003: Response of maize (Zea mays L.) to
rimsulfuron under salt conditions. Acta Societatis Botancorum Poloniae, 12, 93-98
SHANER, D.L. 2003: Herbicide safety relative to common targets in plants and mammals
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STEFANOVIC, L., M. SIMIC, M. MILIVOJEVIC, M. MISOVIC, 2001: Manifestation of
symptoms of herbicide (sulfonylurea) phytotoxic effects after treatment of seed
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STEFANOVIC, L., M. SIMIC, M. ROSUU, M. VIDAKOVIC, J. V ANCETOVIC, M.
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101

Herbologia Vol. 12, No.3, 2011
BIOHERBICIDES - A REAL OR VIRTUAL MEASURE FOR EFFICIENT
WEED CONTROL?
Zvonko Pacanoski
Faculty for Agricultural Sciences and Food, Skopje, R. Macedonia
E-mail: zvonk:op@zf.ukim.edu.mk:; zvonko lav@yahoo.com
Abstract
Bioherbicides are phytopathogenic microorganisms or microbial
phytotoxins useful for biological weed control. Therefore, bioherbicides has
been recognized as a significant biological control strategy. They offer many
advantages-high degree of specificity of target weed; no effect on non-target
and beneficial plants or man; absence of residue build-up in the environment;
effectiveness for managing herbicide-resistant (HR) weed populations.
Furthermore, it has been demonstrated that combinations of some
bioherbicides and synthetic herbicides can be synergistic. Besides many
advantages of bioherbicides, certain factors have been reported to limit the
development of bioherbicides into commercial products. These include
environmental, biological and technical-commercial limitations.
Keywords: bioherbicides, advantages, limitations
Introduction
Development of alternative weed control methods is needed to help
decrease reliance on herbicide use. Bioherbicides are phytopathogenic
microorganisms or microbial phytotoxins useful for biological weed control
applied in similar ways to conventional herbicides (Boyetchko et al., 2002;
Boyetchko and Peng, 2004). The active ingredient in a bioherbicide is,
however, a living micro-organism. Most commonly the organism is a fungus,
hence the term mycoherbicide is often used in these cases (Auld and McRae,
1997). Although the use of fungi and bacteria as inundative biological control
agents (bioherbicides) has been recognized as a significant technological
weed control alternative (Hoagland, 2001; Charudattan, 2001; 2005), it can
be argued that it serves a more important role as a complimentary component
in successful IWM strategies (Hoagland et al., 2007), and not as a
replacement for chemical herbicides and other weed management tactics
(Singh et al., 2006). However, according some authors, bioherbicides offer
many advantages. They include a high degree of specificity of target weed;
no effect on non-target and beneficial plants or man; absence of residue
build-up in the environment; effectiveness for managing HR weed

Z. Pacanoski
populations (Abbas and Boyette, 2000; Hoagland, 2001; Charudattan, 2001;
2005). Besides many advantages of bioherbicides, certain factors have been
reported to limit the development of bioherbicides into commercial products.
These include biological constraints (host variability, host range resistance
mechanisms and interaction with other microorganisms that affect efficacy)
(Auld et al., 2003), environment constraints (epidemiology of bioherbicides
dependent on optimum environmental conditions) (Wheeler and Center,
2001), technical constraints (mass production and formulations development
of reliable and efficacious bioherbicide) (Auld et al., 2003), and commercial
limitations (market size, patent protection, secrecy and regulations) (Auld
and Morin 1995; Scheepens et al. 2001).
Therefore, the objective of this report was to summarize the available
information and bring together advantages and limitations of bioherbicides
use through different examples and experiences.
Successful stories about bioherbicides
Considering the research effort expended in this area, some
bioherbicides are commercialized (Devine®, Collego®, BioMal®,
Camperico®, Biochon®, StampOut® (Kenney, 1986; Bowers, 1986;
Hoagland 1990; Imaizumi et al., 1997; Watson, 2003) and many are
underway to develop and register. Plant pathologists and weed scientists have
identified approximately 200 plant pathogens that are candidates for
development as commercial bioherbicides (Barton, 2005). Some of these are
described here. A fungal pathogen identified as Plectosporium tabacinum
(van Beyma) M. E. Palm, W. Gams et Nirenberg, isolated from naturally
infected cleavers (Galium spp.) plants, showed promise for Galium spp.
control under field conditions. With culture filtrates, 80-90% Galium spp.
control was observed under field conditions (Zhang, 1999). 90% of Sesbania
exaltata [Raf.] Rydb. ex A. W. Hill, was controlled with an effective
bioherbicide, the fungus Colletotrichum truncatum in soybean (Abbas and
Boyette, 2000). The control level was similar to those achieved with the
herbicide acifluorfen in same crop. A bioherbicidal isolate (IMI 361690) of
Myrothecium verrucaria (Alb. & Schwein.) Ditmar:Fr. (MV) showed
mortality levels > 85% for: Chenopodium album L., Senna obtusifulia L.,
Sesbania exaltata (Raf.) Cory, and Datura stramonium L. (Walker and
Tilley, 1997). Trichothecenes produced by an MV isolate from Italy could
inhibit seed germination of the parasitic plant, Orobanche ramosa (Andolfi et
al., 2005). Recently MV was shown to be highly virulent against Portulaca
oleracea, Portulaca portulacastrum, Euphorbia maculata and Euphorbia
prostrata of commercial tomato (Lycopersicon esculentum L.) fields in the
southeastern U.S. (Boyette et al., 2007). Phomopsis amaranthicola, an
104

Bioherbicides- a real or virtual measure for efficient weed control?
indigenous plant pathogen, provided up to 100% control of several
Amaranthus species (Rosskopf et al., 2000). Host range testing of this
organism has not shown infection of soybean, com, sorghum, or wheat.
Mintz et al., (1992) evaluated another fungal pathogen, Microsphaeropsis
amaranthi Ell. & Barth., as a potential bioherbicide for several Amaranthus
species. In this context, in field experiments, eight Amaranthus species
treated with M. amaranthi and the mixture of M. amaranthi and Phomopsis
amaranthicola had severe disease ratings 15 DAT, and mortality ranged from
74% to 100% (Ortiz-Ribbing and Williams, 2006). The fungus Pyricularia
setariae applied at the concentration of 10 5 spores mL- 1 reduced fresh weight
of Setaria viridis (L.) Beauv. by 34% 7 DAT when compared with controls,
whereas a concentration of 10 7 spores mL- 1 reduced fresh weight by 87%.
This efficacy was comparable with that of the herbicide sethoxydim (Peng et
al., 2004). Sesbania exaltata [Raf.] Rydb. ex A.W. Hill was effectively
controlled by 85, 90, and 93%, respectively by Colletotrichum truncatum
(Schwein.) Andrus & Moore at inoculum concentrations of 2.5, 5.0, and 10.0
x 10 6 spores mL-I, respectively (Boyette et al., 2008). The bioherbicidal
efficacy of Dactylaria higginsii has been evaluated in several field studies in
Florida and Puerto Rico. Morales-Payan et al., (2003) have shown that
application of D. higginsii twice (8 + 18 DAE) or thrice (8 + 18 + 25 DAE)
reduced yield loss to 31% and 24%, respectively, as compared to weed-free
pepper. Rosskopf et al., (2003) are examining the potential of D. higginsii as
an alternative to methyl bromide fumigation in an integrated approach to
Cyperus rotndus L. management in a tomato production system. Weed
seedlings between 3 and 5 weeks of age were the most susceptible to the
disease.
Synergism between bioherbicides and chemical herbicides
The concept of combining microbial herbicides with chemical
herbicides or adjuvants has been the subject of considerable research.
Furthermore, it has been demonstrated that combinations of some
bioherbicides and synthetic herbicides can be synergistic (Christy et al.
1993), resulting from lowered weed defense responses caused by the
herbicides, thus making the weeds more susceptible to pathogen attack
(Hoagland, 2000). Christy et al. (1993) reported a synergy between
trimethylsulfonium salt of glyphosate and Xanthomonas campestris against
several weed species. Other synergistic interactions involving chemical
herbicides and bioherbicides have been discovered and some were granted
patents in the USA (Caulder and Stowell, 1988a; 1988b). In these studies the
herbicides acifluorfen and bentazon were the most effective synergists and
provided increased control in several weed : pathogen combinations: (Senna
105

Z. Pacanoski
obtusifolia, formerly Cassia obtusifolia [L.] Irwin & Barneby) and Alternaria
cassiae Jurair & Khan; Aeschynomene virginica [L.] Britton, Stems &
Poggenb. and Colletotrichum gloesporioides; Sesbania exaltata (Raf.) Cory
and Colletotrichum truncatum; and Desmodium tortuosum [SW.] DC.) and
Fusarium lateritium Nees. 12 DAT, Brunnichia ovata [Walt.] Shinners and
Campsis radicans [L.] Seem. ex Bureau were controlled by 88% and 90%,
respectively, through a synergistic interaction between the fungus
Myrothecium verrucaria (Alb. & Schwein.) Ditmar: Fr. and the herbicide
glyphosate (Boyette et al., 2008). Heiny (1994) found that Phoma proboscis
Heiny, at 1 x 10 7 spores mL- 1 and applied with 2,4-D plus MCPP at sublethal
rates controlled Convolvulus arvensis L. more effectively than the herbicide
mixture alone and as effectively as the pathogen at a 10-fold higher rate. The
use of various crop oils (Sandrin et al., 2003; Milhollon et al., 2003) and
invert emulsions (Milhollon et al., 2003) have resulted in improved
bioherbicide efficacy and performance of several biocontrol fungi. For
example, treatments of a fungi M. verrucaria (MY) strain, originally isolated
from Senna obtusifolia L. plus the surfactant Silwet L-77 caused 100%
mortality of Pueraria lobata (Willd.) Ohwi seedlings under greenhouse
conditions, and 90% to 100% control of older Pueraria lobata (Willd.) Ohwi
plants in naturally-infested and experimental plots, respectively (Hoagland et
al., 2007).
Different limitations about bioherbicides
Limitations in bioherbicide development can be classified as either
environmental (temperature and, particularly, humidity as major factors
influencing the efficacy of bioherbicides); biological (mainly host variability
and resistance); technological-commercial (mass production and formulation
which often blocked bioherbicide development) (Auld and Morin 1995; Auld
et al., 2003).
Environmental limitations. Environmental limitations are a constraint to the
effective use of many biological agents, including bioherbicides.
Environmental factors influence formulation performance of bioherbicides as
inoculum production is dependent on sporelation of the formulation. In the
application of bioherbicides, environmental conditions prevailing in the
phyllosphere of plants are frequently hostile for biological control agents
(Andrews, 1992). A requirement for more than 12 h of dew period for severe
infection by a pathogen, has been reported for several potential bioherbicides
(Morin et al., 1990; Makowski, 1993) and this may limit the efficacy of the
bioherbicide in the field. Temperature generally has not been considered to
be as critical as moisture for mycoherbicide, although field efficacy of
Colletotrichum orbiculare in controlling Xanthium spinosum L. is reduced by
106

Bioherbicides- a real or virtual measure for efficient weed control?
high temperature conditions after inoculation of plants (Auld et al., 1990).
However, dew period length requirement and temperature typically interact
(McRae and Auld, 1988).
Soil environment, moisture and the nutrient status of the soil can
influence the physiology of target plants and, therefore, their interaction with
aerial applied bioherbicides (Altman et al. 1990). Pre-emergence application
has been considered as an alternative approach to overcome some of the
environmental stresses imposed upon propagules applied onto the foliage or
soil surface (Boyette et al., 1991). In that context, the incorporation into the
soil of Colletotrichum truncatum (Schw.) Andrus and Moore, a potential
bioherbicide for the control of Sesbania exaltata (Raf.) Rydb. ex A. W. Hill,
resulted in a 95% kill of the emerging weed seedlings (Jackson et al., 1993).
There are many environmental limitations to applying bioherbicides
and maintaining their efficacy in water, as well (Charudattan et al., 1990).
For control of emergent weeds a biocontrol agent would need to have a broad
epidemiological adaptation to contend with varying conditions between
surface and bottom, as well as across even small bodies of water. Oxygen
concentration, temperature, light intensity, and salinity are just four of the
variables to contend with (Auld and McRae, 1997).
Biological limitations. It is desirable for a bioherbicide to act relatively
quickly and have sufficient efficacy to control weeds. Unfortunately, many of
the weed pathogens discovered may provide only partial control of only one
weed species, even under ideal conditions (Charudattan, 2005). Biological
constraints including host variability and resistance, as well (Auld, 2003).
Namely, within a population of plant species there will usually be a range of
genetically diverse biotypes (Burdon, 1987) which may include some
resistant types, just as there may be a range of biotypes of a weed species it is
usual to fmd a range of biotypes of microorganisms (Weidemann and
TeBeest, 1990), for example within fungal species, with slightly different
host ranges (Auld et al., 1992), so that there is potential to mix and vary the
biotypes of a species used as a bioherbicide DeJong et al. (1990) addressed
non-target plant safety in relation to the potential use of Chondrostereum
purpureum (Pers ex Fr.) Pouzar to control Prunus serotina Erhr. in
coniferous forests by modelling the dispersal of spores and therefore
quantitatively assessing the risks to susceptible fruit trees outside the forest.
Concerns have been raised regarding the potential for sexual or asexual gene
exchange between bioherbicide strains and strains attacking distantly related
crop plants (TeBeest et al., 1992).
Technological-commercial limitations. Several technological limitations
have been identified that could prevent the widespread use of bioherbicides.
Pathogenical strains, formulation method and the interaction of these two
parameters significantly affect the shelf life of the formulations at room
107

Z. Pacanoski
temperature (Hebbar et al., 1998). High concentrations and the alteration of
formulations are needed to increase bioherbicide activity (Patzoldt et al.,
2001). The most challenging aspect of formulating bioherbicides is to
overcome the dew requirement that exists for several of them. Attempts to
overcome this limitation have included developing various water-retaining
materials; invert and vegetable oil emulsion formulations (Boyette, et al.,
1999) and granular preemergence formulations (Watson and Wymore, 1990),
considered as a promising approach to make pathogens less dependent on
available water for initial infections to occur (Womack et al., 1993).
Experiments conducted with a number of potential bioherbicides have
demonstrated that an invert emulsion allowed infection to occur in the
absence of available water and reduced the need to apply high dosages of
inoculum (Amsellem et al., 1990). Connick et al., (1991) have recently
developed an invert emulsion formulation exhibiting lower viscosity and
greater water-retention properties. The use of low concentrations of vegetable
oils with an emulsifying adjuvant was also found to enhance efficacy of
C.orbiculare in inciting disease on X. spinosum L. in the absence of dew in
controlled environments (Auld, 1993). Unfortunately, these oil emulsions
were not as efficient in the field. Although these formulations have been
shown to overcome dew requirements and reduce the spore concentrations
required (Womack et al. 1996), they contain a high percentage of oil (>30%)
which makes them expensive and very viscous, typically requiring special
spraying equipment such as air-assist nozzles, and because of the high oil
content, is likely to produce phytotoxic effects on non-target plants. Recently,
Chittick et al. (2003) reported a spray drying process to encapsulate hyphal
fragments of a Phomopsis sp., fungus for the control of Carthamus lanatus L.
The main limitation in the use of solid (dry) forms of bioherbicide is that they
must await suitable, moist conditions for fungal growth and infection.
Moreover, during this waiting period the living active ingredients must
survive in the field.
The simplest liquid formulations of bioherbicides are water
suspensions of spores often with a small amount of wetting agent. However,
under ideal conditions for fungal infection, simple aqueous suspensions can
be successful in the field (Auld et al. 1990). Pathogenicity of an aqueous
mycelial inoculum of Alternaria eichhorneae Nag Raj & Ponnapa in a
controlled environment experiment was improved with hydrophilic polymers
such as gellan gum, alginates and the polyacrylamide (Shabana et al.,
1997).These are generally used as standards against which to compare more
complex formulations. Although several polymers retained considerably
more water after 6-8 h than the water suspension controls, no increase in
efficacy of the fungus C. orbiculare was found (Chittick and Auld, 2001).
Simple vegetable oil emulsions (containing 10% oil and 1% of an
108

Bioherbicides- a real or virtual measure for efficient weed control?
emulsifying agent) showed promise in reducing dew dependence in
controlled environment studies using C. orbiculare on X. spinosum L. (Auld,
1993). However, in the field, the efficacy of these formulations was
inconsistent (Klein et al. 1995).
A novel bioherbicide formulation using a complex emulsion was
disclosed by Auld (2002). It is water-in-oil-in-water (WOW) emulsion
which contains at least one lipophilic surfactant, at least one hydrophilic
surfactant, oil and water. Although used in the pharmaceutical (Marti­
Mestres and Niellond, 2002), cosmetic (De Luca et al., 1990) and food
industries (Cindio et al., 1991), WOW emulsions do not appear to have been
widely used in agricultural or horticultural technology. Although promise for
improvement of liquid formulations of bioherbicides have been made, genetic
manipulation of fungi offers a wide range of opportunities to modify
formulations and to improve bioherbicide performance (Pilgeram et al.
2002).
Taking into considerations previous mentioned limitations, the
development of bioherbicides by commercial firms would involve additional
costs without secured returns. The cost of mass production of
microorganisms for bioherbicides in submerged culture or in solid-state
systems, which would vary from one bioherbicide to another, is relatively
high (Ghosheh, 2005). In addition, the low market potential of several
efficient bioherbicide candidates indicates that market size could be a
constraint for developing such herbicides. On this basis, companies are
unsure that development and registration costs will be recovered (Auld and
Morin, 1995).
Conclusions
The bioherbicides approach is gaining momentum. New bioherbicides
will find place in irrigated lands, wastelands as well as in parasite weeds or
resistant weed control. Research on synergy test of pathogens and herbicides
for inclusion in IWM, developmental technology, fungal toxins, and
application of biotechnology, especially genetic engineering is required.
Bioherbicides will not solve all of the environmental and weed management
problems associated with synthetic herbicides, nor will replace the current or
future arsenal of synthetic herbicides. Rather, their role will probably be
complimentary components in successful IWM systems, and in the discovery
of novel phytotoxins with new chemistries and new molecular sites of action.
Continued research on these areas is important in order to fully understand
interactions of microorganisms and plants (crops and weeds), and to discover
new phytopathogenic microorganisms or microbial phytotoxins useful as
bioherbicides.
109

Z. Pacanoski
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114

Herbologia Vol. 12, No.3, 2011
A STUDY OF THE COMPETITIVE ABILITY OF VELVETLEAF
(ABUTILON THEOPHRASTI MEDIC.) IN A FIELD EXPERIMENT IN
PARSLEY
Preliminary Communication
Viktor Nagy, Erzsebet Nadasy, Eva Lehoczky
Institute of Plant Protection, Georgikon Faculty, University of Pannonia, Deale Ferenc Str.
57, 8360 Keszthely, Hungary, e-mail: nagyyiktor.georgikon@gmail.com
Abstract
Velvetleaf (Abutilon theophrasti Medic.) is one of the important,
spreading, hazardous weed species in Hungary. The spreading of this weed is
based on its reproductive biology and furthermore on its strong competitive
ability and allelopathic effect. Its competition against other plants for water
and nutritions is significant. Its competitive ability has been studied in several
crops, where a strong yield-reducing effect was measured even under low
velvetleaf density.
Our additive experiment was carried out in a 3 sq metre small parcel
(3x1 m) in parsley with four replications in 2010. The experimental field was
located in Apatfalva, Bekes county, Hungary. Three different weed densities
were adjusted (2, 5 and 10 velvetleaf plants per m 2 ) and they were compared
to a weedless control field. The weight of the fresh stems and roots of the
crop was measured in each parcel and the weight and length of 10 randomly
chosen roots was also measured. The root yield was classified and the
quantity and rate of first class and processing root were determined per
parcel.
We found that root yield was reduced due to the increasing weed
density, even 2 weeds per sq metre reduced the yield significantly. The
greatest difference was observed in the quality of the yield, increasing
velvetleaf density extended the amount of branching. The average weight of
the roots was also reduced in the treated parcels compared to control ones.
Velvetleaf was considered to have a strong competitive ability against
parsley. Even in low density, velvetleaf negatively affected the quality of root
yield and increased the rate of processing roots and wastrel.
Keywords: Abutilon theophrasti, parsley, additive experiment, competition
Introduction
Velvetleaf (Abutilon theophrasti Medicus 1787), according to some
authors (Vavilov, 1951; Li, 1970; Spencer, 1984; Tutin et al., 1986; Warwick

Nagy eta!.
& Black, 1988), is an annual weed, native of China. Other sources indicate
that its gene centre is possibly in India (Shaw et al., 1974; Flint et al., 1983).
In China it was cultivated as a fiber and medical plant (Czimber et al., 1994;
Kazinczi et al,. 2001).
From its origin this weed presumably got into South-Eastern Europe,
Southern Russia, the west coast of the Mediterranean Sea and into Hungary
through the Balcan and North-Africa (Tutin et al., 1986; Warwick & Black,
1986; Kazinczi et al., 2001).
Until the 1700's it was considered as a potential fiber crop then it has
become a major weed in the United States (U.S. Department of Agriculture,
1970, Spencer, 1984) and in Canada (Ontario Ministry of Agriculture and
Food, 1974; Lindsay, 1953; Montgomery, 1957; Rousseau, 1968; Warwick &
Black, 1986). This species is spreading to the south and causing harm to
agricultural production in Mid-America, for example in Mexico (Dominquez
Velanzuela et al., 2003). The seeds of velvetleaf got into Scandinavia with
infected com, soybean and sunflower shipments in the early 20th century
(Hansen, 1972; Hylander, 1970; Suominen, 1979). The weed was introduced
in Great Britain by birdseeds (Hanson & Mason, 1985). Nowadays it is
present all across Europe, for example in the Netherlands (Mennema, 1982),
in Germany (Fukarek & Henker, 1983; Viehweger & Dittrich, 2004), in
Austria (Hain, 2003), in Switzerland (Bohren et al., 2008), in Poland (Kita et
al,. 2003), in the Czech Republic (Jehlik et al., 1988), in Croatia (Hulina,
1995) and in Bosnia-Hercegovina (Dikic et al., 2007). In addition it is present
as a noxious weed in the whole of Asia, in North-Africa, in Marocco (Tanji
& Taleb, 1997), in South-America, in Australia (Hanf, 1983; Holm et al.,
1979) and in Japan (Kuokawa et al., 2003; Watanabe, 2007).
This species was probably introduced in Hungary as an ornamental
plant (Terp6, 1987). As a weed it was first described by the botanist
Szaniszl6 Priszter, in Budapest (1945-1950). The rate of this plant is
continouosly growing and in 1994 it was considered to be a dangerously
spreading weed. In the fourth national weed survey it was positioned in the
27th place, but in the com fields of Zala county in 2007/2008 this weed was
ranked the lOth most dangerous. On the whole it is the 15th most important
weed of com considering its dominance (Novak et al., 2009).
Velvetleaf (Abutilon theophrasti) is causing an increasing problem in
the cultivation from year to year. The rate of the plant - as in case of other
warm season plants- increased in the last decade dramatically (Szoke, 2001).
Its competitive benefit on crop plants is due to the powerful growth and
excellent temperature and drought tolerance of this weed (Patterson, 1992).
Several researchers have already examined the competitive and yieldreducing
ability of velvetleaf in several crops, for example in com (Czimber
& Domotor, 1985; Czimber et al., 1987; Varga et al., 2000; Werner et al.,
116

A study of the competitive ability of velvetleaf (Abutilon theophrasti) in a ...
2004; Kovacs et al., 2006; David et al., 2006; David & Kovacs, 2007;
Kazinczi et al., 2007), in sunflower (David et al., 2006), in soybean (Gressel
& Holm, 1964; Retig et al., 1972; Eaton et al., 1976; Oliver, 1979; Colton &
Einhellig, 1980; Dekker, 1981; Sadeghi et al., 2002; 2004) in sugarbeet
(Schweizer & Bridge, 1982; Renner & Powel, 1991; Bordner et al., 2004;
Haensel, 2005) and in grain sorghum (Traore et al., 2003).
According to some authors the yield-reduction of crop plants is a
result of the competitive advantage of velvetleaf. Hagood et al. (1980),
McConnaughay & Coleman (1998) and Holt & Boose (2000) were focusing
on competition for water, while Stoller & Wooley (1985), Sattin et al. (1992)
and Jurik & Akey (1994) on competition for light. Others suggest that
competition for nutrients is the factor, which is responsible for the strong
competitive ability ofvelvetleaf (Oliver, 1979, Roeth, 1987).
Materials and methods
The aim of our experiment was to measure the competitive ability of
velvetleaf (Abutilon theophrasti) in parsley (Petroselinum crispum Mill.)
culture.
The open-field, small-parcel additive experiment (cca. 200 parsley
plants per parcel) was set up in the field of Antal es Tarsa Ltd., Apatfalva,
Bekes county, Hungary, in 2010.
The study field had a slightly alkalide chemozem soil, with a good
humus supply. The experiment was carried out in the 'Mak6i hosszu'
cultivar, sown in rectangular beds, after autumn wheat forecrop in 3 sq metre
sized parcels in 4 replications. The parameters of the soil are the following:
humus - 3.2%, pH-KCL- 7.3, CaC03- 6.61 %; P20s- 323.6 mg/kg, K20-
362mg/kg.
Three different weed densities were adjusted (2, 5 and 10 velvetleaf
plants per m 2 ) and they were compared to a weedless control field. During
the period of the experiment handmade hoeing managed to exclude other
weed plants. The weight of fresh stems and roots of the crop was measured in
each parcel. From each parcel the weight and length of 10 randomly chosen
roots was also measured. The root yield was classified, two classes were
made: first class and processing root (unclassified) and the rate of classes was
determined per parcel. The data were statistically analysed with SPSS.
Results and discussion
During the evaluation of the whole root yield in each parcel, we found
that increasing velvetleaf density leads to root yield decreasing, but the rate
of the decrease was not considerable. The results of the regression analysis
117

A study of the competitive ability of velvetleaf (Abutilon theophrasti) in a ...
First class yield was 78.5% of the whole in the control field, while in
parcels with ten velvetleaf plants per m- 2 this ratio dropped to 44.4%.
Different treatments significantly reduced the amount of first class, nonbranching
roots, at 5% significance level. There is a strong correlation
between the cover percentage of velvetleaf plants and the quality of first class
yield. The different treatments were responsible for 63.3% of the decrease
while 36.7% of the loss was caused by other factors.
Compared to the control field, 2, 5, and 10 weed m- 2 weed densities
decreased the quantity of first class yield by 20.6%, 27.85% and 52%,
respectively.
An increase of one velvetleaf plant density per squaremetre reduces
the number of first class roots by 0.63 kg, in average, which is approximately
a 2 tonnes per hectare reduction (Figure 2).
Branching roots were placed into the group of unclassified, processing
roots. The rate of branching roots was only 21.5% of the total yield in the
control field, while increasing velvetleaf density resulted in a growing rate of
unclassified roots. From the total yield two weeds per squaremetre density
resulted in 35.63% unclassified roots, ten weeds per squaremetre in 56.3%.
Focusing on yield quantity, one velvetleaf increase results in an
average of 0.4kg increase in the quantity of unclassified roots per parcel.
There a strong relation between velvetleaf density and the quantity of
unclassified roots (R= 0.75) (Figure 3). The rate of difference is statistically
significant at 5% significance level.
We found that increasing velvetleaf density significantly reduced the
number of first class, non-branching roots, at the same time branching roots
increased. The yield reducing effect of velvetleaf was statistically not
verifiable.
From each parcel 10 parsley plants were randomly chosen and we
measured the average length and weight of the roots (Figure 4).
Figure 3: The effect of vel vetleaf density on the quality of parsley
119

17
5
Nagy eta!.
• y = .(),1756x + 11,034-
R 2 = 0,0607
•
•
• • • ....
•
0 2 3 4 5 6 7 8 9 10 11
Density of velvetleaf (munber of weed m""}
Figure 7.: The effect of treatments on parsley fresh shoot weight
The quantity of leafy yield showed a decreasing tendency as a
response to higher velvetleaf density, but the treatments are responsible for
only 6% of the difference. The correlation between treatments and the
quantity of leafy yield is very slight (R=. -0.29), the difference is not
significant. We can state that velvetleaf did not affect parsley upground yield
notably.
Conclusions
The yield reducing effect by velvetleaf (Abutilon theophrasti) was
demonstrated in a parsley field. The quantity of root yield dramatically
decreased in the weedy parcels, compared to the weedless control field, a
density of 10 velvetleaf per mete.-2 caused 15% root yield reduction. (Varga
et al., 2000; Kovacs et al., 2006; David et al., 2006; David & Kovacs, 2007;
Kazinczi et al., 2007). The rate of the yield reducing effect corresponds with
the results of Schweizer & Bridge (1982) in sugarbeet. 2 velvetleaf
plants/square metre is detrimental of the yield, parsley is intolerant to even
this relatively low weed density (Renner & Powel, 1991). There is yet no
literature data on the effect of velvetleaf competition on the quality of the
yield. The quantity of first class parsley root was smaller as a response to
higher weed density, while the quantity of branching, processing or
unclassified roots increased. Even the density of 5 pieces per m- 2 of Abutilon
theophrasti weed significantly increased the quantity of unclassified roots
and reduced the quantity of well classified yield.
Earlier literature data suggest that the branching of parsley roots can
be a result of water deficit. Nevertheless velvetleaf is in a competition with
crop plants for water primarily, water deficit can not be a primary factor in
such a rainy year like 2010 (Gy11r6, 1968; 1981; 1983). The average root
length and weight also showed a decreasing tendency due to the increasing
weed pressure. Presumably, the allelopathic effect of Abutilon caused the
irregular growth of the roots. Several literature data suggest that velvetleaf
122

A study of the competitive ability of velvetleaf (Abutilon theophrasti) in a ...
has an inhibitor effect on root growing (Retig et al., 1972; Nagy & Nadasyne,
2009, Nagy et al., 2010, Galzina et al., 2011), which is caused by the arginin
content of the plant (Elmore, 1980; Paszkovski & Kremer, 1988). If there is
much rainfall, alleloptahic effect can intensify, which is a possible
explanation for the irregular root growth (McPherson & Muller, 1969; Del
Moral & Muller, 1970; David & Nagy, 2010).
If the velvetleaf cover percentage is higher, the concentration of
washed out allelochemicals can increase, which can be the reason for the
reduced and irregular root growth. Due to higher concentration, root growing
is increasingly blocked and the rate of branching roots are higher (Rice,
1984).
In connection with velvetleaf competition the literature focuses on the
reduction occured in the upground parts and fruit of crop plants. Any
significant reduction of parsley foliage has not been measured yet (Sadeghi et
al., 2004).
Acknowledgement We would like to express our great honour to Antal es Tarsa Ltd. for
granting us the experimental conditions.
Our study was funded by the tender "Livable Environment and Healthier People -
Bioinnovation and Green Technology Research at the University of Pannonia" (TAMOP-
4.2.2.-08/1!2008-00 18)
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127

Herbologia Vol. 12, No.3, 2011
ALLELOPATHIC EFFECTS OF PARTHENIUM HYSTEROPHORUS L.
ON SEED GERMINATION AND GROWTH OF SOYBEAN, MUNG
BEAN AND MAIZE
Preliminary Communication
Adres Khan, Ijaz Ahmad Khan, Rahamdad Khan and Shah Zarin
Department of Weed Science, Khyber Pakhtunkhwa Agricultural University Peshawar,
Pakistan
ijazahmadk@hotmail.com
Abstract
Parthenium hysterophorus L. being an invasive weed in Pakistan is a
threat to the biodiversity and agro-ecosystem. To investigate the allelopathic
potential of this weed, a laboratory based experiment was conducted during
July 2009, in Weed Science Research Laboratory, Department of Weed
Science, Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan.
The fresh leaves of P. hysterophorus were collected, dried in the oven and
then ground. Then the powder was soaked in tap water 25 g L- 1 , 50 g L- 1 •
Ten seed of soybean, mung bean and maize were placed in Petri dishes
separately and different concentrations of extracts were applied according to
the need. Control was also included for comparison. The experiment was laid
out in four replications. The results showed that with the increasing leaves
extract concentration of P. hysterophorus, the germination mean, shoot
length, shoot weight, root length and root weight of the soybean, mung bean
and maize were significantly decreased. The tolerance of the soybean to the
extract concentration of P. hysterophorus was higher than the other two
species. Therefore it is noted that the infestation of P. hysterophorus can
pollute the soil by accumulating toxic chemicals and affect the biodiversity
and agro-ecosystem. Our fmding suggestion is to prevent the P.
hysterophorus infestation by weed management practices.
Keywords: Parthenium hysterophorus, allelopathy, soybean, mung bean, maize.
Introduction
Nowadays, allelopathy is a concern in research involving sustainable
agriculture, also referred to as organic, low input, biodynamic, or resource
conserving. Allelopathy has been used in agricultural practices such as weed
control, intercropping, nutrient recycling, and low-external input farming
practices (Chou, 1986; Fisher, 1987; Rizvi and Rizvi, 1987).

Khan etal.
Parthenium weed is known to be allelopathic (Adkins and Sowerby,
1996). It has allelopathic effects and drastically retards the growth of many
species (Tefera, 2002). In the past two decades much more work has been
done on plant-derived compounds as environmentally safe alternatives to
herbicides for weed control (Duke et al., 2002). Parthenium weed can be
found along the roadsides and even in agricultural crops, like wheat and
maize in Khyber Pakhtunkhwa.
In Pakistan, legumes and maize are the two important crops. Legumes
family includes all types of beans and peas as well as soybeans, peanuts,
alfalfa, and clover. The seeds of many legumes are an important food source
worldwide. They are very rich in both oil and protein and are usually
inexpensive so much, so they are often referred to as "poor man's meat." The
high protein content of legumes is associated with nodules of nitrogen-fixing
bacteria that form on their roots. These bacteria are able to convert free
atmospheric nitrogen into a form that can be used by plants in the making of
proteins and other nitrogen compounds.
Parthenium hysterophorus
As we are aware in Pakistan, that legumes and maize are always in
high demand, so their production in our country is very important. One of the
reasons for the low production of these crops in Pakistan is the allelopathic
affect of some invasive weeds like Parthenium hysterophorus L. These
weeds suppress the legumes or maize seed gennination, growth, and
production. In order to find out the affects of the allelochemicals of
Parthenium hysterophorus L. on soybean, mung bean and maize seeds
germination at different concentrations of Parthenium extract solution, the
experiment was conducted in the laboratory of the Department of Weed
130

Allelopathic effects of Parthenium hysterophorus on seed germination and ...
Science Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan
with the following objectives.
1. To know the allelopathic affects of Parthenium hysterophorus
on the seed germination of legumes and maize.
2. To check the seed germination of legumes and maize under
different extract concentrations of Parthenium hysterophorus solution.
3. To investigate the allelopathic potential of Parthenium
hysterophorus.
Materials and methods
A laboratory based experiment was conducted in the Weed Science
Research Laboratory, Department of Weed Science, Khyber Pakhtunkhwa
Agricultural University Peshawar Pakistan during 2009, to investigate the
allelopathic affect of Parthenium hysterophorus L. leaf extract on seed
germination and growth of soybean, mung bean and maize. Parthenium
hysterophorus L. plants were collected at their mature stage and dried in the
oven for 48 hours at 65·c temperature. The plants were ground into a dried
powder and then soaked for 24 hours in tap water. Then the mixture of
Parthenium powder and tap water was filtered from muslin cloth in different
bottles at different concentrations. The concentrations were 0 g L- 1 (control),
25 g Parthenium powder L- 1 of water, 50 g Parthenium powder L- 1 of water.
Ten seeds of each crop were placed in Petri dishes on tissue paper, and the
tissue paper was used as a medium for germination. There were three
treatments i.e. 0 g L- 1 (control), 25 g L- 1 , 50 g L- 1 , replicated four times. The
concentrations of Parthenium extract solution were applied to Petri dishes
according to the need of the plants. After 12 days, the data on seed
germination, shoot length (em), root length (em), shoot weight (g) and root
weight (g) and were recorded using electronic balance and a graduated scale.
The collected data were analyzed through Analysis of varaiance (ANOV A)
techniques and the least significant difference (LSD) at (P :::; 0.05) was
computed by procedure mentioned by (Steel et al., 1997).
Germination mean
Results and discussion
The average mean of all replications in Table 1 shows that the
maximum seed germination (97.5%) was recorded in maize in the control
(check), followed by soybean (97.50%), while the minimum seed
germination (95.0%) was observed in mung bean in control. The minimum
131

Khan eta!.
seed germination (2.50%) was recorded in mung bean in 50 g L- 1 extract
solution of Parthenium. The result also shows that the seed germination was
decreased by increasing the concentration of Parthenium extracts up to 25 g
L-1.
Similar results are reported by Dhawan (1995) that aqueous extracts
of P. hysterophorus, completely inhibited the seed germination of okra,
Trifolium alexandrium, and wheat.
Table 1. Germination mean(%) at different concentrations of Parthenium
hysterophorus extract
Control 25 g L- 1 50 g L- 1
Mean
Soybean 97.50 a 30.50 b 5.00c 44.16 a
Mung bean 95.00 a 37.50 b 2.50c 45.00 a
Maize 97.50 a 35.00 b 12.50 c 48.33 a
Mean 96.66 a 34.16 b 6.66 c
LSD o.o5 0.116 0.511 5.740
Shoot length
The maximum shoot length (4.485 em) in Table 2 was observed in
mung bean in control followed by maize (2.525 em) in all replications, while
in control the minimum shoot length (1.435 em) was recorded in soybean.
The minimum shoot length (0.393 em) was recorded in soybean under 50 L- 1
of extract solution in all replications. It shows that the shoots of soybean are
more susceptible to the allelechemicals of Parthenium weed.
The results of the present experiment reveal that the shoot length was
decreased by increasing the concentration of Parthenium extracts up to 25 g
L- 1 • While under 50 g L- 1 of extract solution of Parthenium, more decrease
occurred in the shoot length of soybean, mung bean and maize in all the
replications.
Table 2. Shoot length (em) at different concentrations of Parthenium weed
Control 25 g L- 1 50 g L- 1
Mean
Soybean 1.435 d 1.353 d 0.393 e 1.060 c
Mung bean 4.485 a 3.645 b 1.000 de 3.043 a
Maize 2.525 c 2.455 c 0.850 de 1.943 b
Mean 2.815 a 2.484 a 0.748 b
LSD o.o5 0.961 0.799 0.131
132

Allelopathic effects of Parthenium hysterophorus on seed germination and ...
Root Length
The maximum root length (2.793 em) was recorded in mung bean in
Table 3 followed by maize (2.053 em) in control in all replications, while in
control the minimum root length (1.195 em) was recorded in soybean. The
minimum root length (0.400%) was recorded in soybean under 50 g L- 1 of
extract solution in all replications. It shows that the roots of soybean are more
susceptible to the allelechemicals of Parthenium weed.
The present fmdings also show that like the shoot length the root
length also decreased by increasing the concentration of Parthenium extracts
up to 25 g L- 1 • While there was more decrease occurred in the root length of
soybean, mung bean and maize in all replications under 50 g L- 1 of extract
solution of Parthenium.
Table 3. Root length of soybean, mung bean and maize (em) at different
concentrations of Parthenium weed
Control 25 g L- 1 50 g L- 1
Mean
Soybean 1.195 c 1.125 c 0.400 d 0.907 c
Mung bean 2.793 a 2.498 ab 0.650 cd 1.980 a
Maize 2.053 b 1.872 b 0.600 cd 1.508 b
Mean 2.013 a 1.832 a 0.550 b
LSD o.os 0.170 1.991 0.048
Shoot weight
The different level of the concentration also effects the shoot weight
of the examined crop seeds. The maximum shoot weight (0.603 g) was
observed in mung bean in the control followed by maize (0.221 g) in all
replications, while in the control the minimum shoot weight (0.164 g) was
recorded in soybean in Table 4. The minimum shoot weight (0.033 g) was
recorded in soybean under 50 g L- 1 of extract solution in all replications. This
shows that the shoot weight of soybean is also more susceptible to the
allelechemicals of Parthenium weed.
Like other parameters, shoot weight was also decreased by increasing
the concentration of Parthenium extracts up to 25 g L- 1 and more decrease
occurs when concentration increases up to 50 g L- 1 of extract solution of P.
hysterophorus weed.
Our result also concur with these by Javaid et al. (2006) who
reported that the aqueous root and shoot extracts of three alleopathic crops,
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Khan eta!.
viz. sunflower ( Helianthus annuus L.), sorghum (Sorghum bicolor L.) and
rice (Oryza sativa L.) has allelopathic affects on germination and growth of
the noxious alien weed Parthenium hysterophorus L.
Table 4. Shoot weight of soybean, mung bean and maize against different
concentrations of Parthenium weed
Control 25 g L- 1
L-1
50 g Mean
Soybean 0.164 be 0.093 be 0.033 c 0.096 b
Mung bean 0.603 a 0.375 ab 0.073 c 0.351 a
Maize 0.221 be 0.158 be 0.260bc 0.213 ab
Mean 0.329 a 0.209 ab 0.122 b
LSD o.os 0.301 0.044 0.105
Root Weight
Root weight in Table 5 shows that the maximum root weight (0.122
g) was recorded in maize followed by mung bean (0.117 g) in the control in
all replications, while in the control the minimum root weight (0.072 g) was
recorded in soybean. The minimum root weight (0.013 g) was recorded in
soybean under 50 g L- 1 of extract solution in all replications. That shows that
the weight of the roots of soybean is also more susceptible to the
allelechemicals of Parthenium weed. The ratio of root weight was decreased
by increasing the concentration ofParthenium extracts up to 50 g L- 1 •
These results are in agreement with findings of Batish et al. (1997)
who reported that Parthenium hysterophorus has herbicidal activity against
Ageratum conyzoides under in vitro conditions. It inhibited/retarded
germination of A. conyzoides at concentrations ranging from 0.02 to 0.1
mg/ml. In another study Adkins and Sowerby (1996) also reported that
different kinds of allelopathic chemicals were released from Parthenium
leaves which have allelopathic affects.
134

Allelopathic effects of Parthenium hysterophorus on seed germination and ...
Table 5. Root weight of soybean, mung bean and maize at different
concentrations of Parthenium weed
Control 25 g L- 1 50 g L- 1
Mean
Soybean 0.072 cd 0.060 d 0.013 e 0.048 b
Mung bean 0.117 ab 0.094 be 0.024 e 0.078 a
Maize 0.122 a 0.060 d 0.019 e 0.067 a
Mean 0.104 a 0.071 b 0.019 e
LSD o.os 0.641 0.016 0.055
All the results of the experiment show that Parthenium weed has a
significant drastic affect on seed germination (%) and on the length and
weight of the roots and shoots of soybean, mung bean and maize due to
allelochemicals which are released by Parthenium weed.
Conclusions
Parthenium hysterophorus is an invasive weed in Pakistan and is a
threat to the biodiversity and agro-ecosystem. This weed species has the
potential to adversely affect the other crops by releasing toxic chemicals. The
different extract concentrations of P. hysterophorus show various results on
the seed germination of soybean, mung bean and maize. The experimental
results show that with the increasing leaves extract concentration of P.
hysterophorus , the germination mean, shoot length, shoot weight, root length
and root weight of the soybean, mung bean and maize were significantly
decreased.
The tolerance of the soybean to the extract concentration of
Parthenium weed was higher than the other three species. Therefore it is
noted that the infestation of P. hysterophorus can affect the natural ability of
the soil, biodiversity and agro-ecosystem.
Therefore the infestation of Parthenium hysterophorus should be
discouraged through suitable and effective weed management practices to get
maximum yield.
135

Khan eta!.
References
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136

Herbologia Vol. 12, No.3, 2011
Instruction to Authors in International Journal Herbologia
One copy of manuscript in English should be submitted by e-mail or
as a hard (paper) copy and a compact disc.
Manuscripts should be computer typed in MS Word, single spaced,
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(address of the autors, keywords and list of references with font size 10). The
text lines should be justified. The length of the paper can be up to eight
pages.
The paper should start with the title of the article, the names of each
author, his/her institution, address and e-mail address.
Abstract would not exceed 300 words or 20 lines. Keywords, up to
two lines long, should be listed below the abstract.
Main text includes introduction, materials and methods, results and
discussion. Footnotes should be avoided. SI units should be used. Reference
list should be ordered alphabetically. Examples: AUTHOR, X.Y. & Z.Q.
AUTHOR, 2001: Title of article, Journal title in Italics, 12, 78-84. Or:
AUTHOR, A., B. AUTHOR, 1998: Book title (ed. GH Editor). Publisher,
Place, Country.
Figures and tables should be numbered consecutively and should have
an appropriate caption or legend.
Scientific names and latin words et al. should be in italic. When a
plant name is repeated, it can be abbreviated, e.g. C. album. For crop plants,
common English names are used, but the scientific name can be given in
parentheses at the first mention in the main text, e.g. oats (Avena sativa).
Both British and American forms of common names can be used (e.g. com
and maize, alfalfa and lucerne etc.), up to the choice of the author. For
herbicides and other chemicals, in Materials and methods, one should state
common approved names and trade names, e.g. glyphosate (Roundup 360 a.i.
L- 1 , Monsanto), and thereafter only trade names. Dose of herbicides should
be expressed in terms of active ingredient (e.g. a.i. ha- 1 ).

Herbologia Vol. 12, No. 3, 2011
Referees for the papers in the Herbologia Vol. 12, No.1, 2, 3/2011
Daniela Chodova, Prague, Czech Republic
Ivica Dalovic, Novi Sad, Serbia
Mirha Dildc, Sarajevo, B&H
Drena Gadzo, Sarajevo, B&H
Katerina Hamouzova, Prague, Czech Republic
Rabiaa Haouala, Sousse, Tunisia
Gabriela Kazinci, Kaposvar, Hungary
Mira Knezevic, Osijek, Croatia
Senka Milanova, Kostinbrod, Bulgaria
Ljiljana Nikolic, Novi Sad, Serbia
Adisa Parle, Sarajevo, B&H
Sulejman RedZic, Sarajevo, B&H
Milena Simic, Belgrade, Serbia
Lidija Stefanovic, Belgrade, Serbia
Taib Saric, Sarajevo, B&H
138