herb. 9, 2 - anubih

UDK 63/66 ISSN 1840-0809 

HERBOLOGIA 

An International Journal on Weed Research and Control 

Vol. 9, No. 2, October 2008

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) 

Vladimir Borona (Ukraine) 

Daniela Chodova (Czech Republic) 

Mirha Đikić (B&H) 

Azra Hadžić (B&H) 

Gabriella Kazinczi (Hungary) 

Senka Milanova (Bulgaria) 

Ševal Muminović (B&H) 

Shamsher S. Narwal (India) 

Zvonimir Ostojić (Croatia) 

Danijela Petrović (B&H) 

Lidija Stefanović (Serbia) 

Taib Šarić (B&H) 

Dubravka Šoljan (B&H) 

Štefan Týr (Slovakia) 

Editor-in-Chief: Prof. Dr. Taib Šarić 

Technical Editor: Dr. Mirha Đikić 

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CONTENTS 

Page 

1. R. Nakova: Cirsium arvense (L.) Scop. competition with 

winter wheat…………………………………………………….......... 1 

2. Z. Kovačević, D. Petrović N. Herceg: The summer aspect 

of weed flora in the vineyards of Herzegovina..................................... 9 

3. G. Hassan, I. Khan, N. Khan : Distribution of weed flora in 

chickpea crop in district Dera Ismail Khan, Pakistan....................... 21 

4. A. Knežević, S. Stojanović, Lj. Nikolić, B. Ljevnaić, D. Džigurski, 

D. Milošev: Ecological and plant-geographic analysis of the weed 

flora in organic production of brassicas …………………………... 29 

5. B. Konstantinović, M. Meseldžija, N. Mandić: Distribution of 

Asclepias syriaca L. on the territory of Vojvodina and possibilities 

of its control………………………………………………………….39 

6. A. Aleksieva, P. Marinov-Serafimov: A study of allelopathic 

effect of Amaranthus retroflexus (L.) and Solanum nigrum (L.) 

in different soybean genotypes…………………………………...... 47 

7. M. Đikić, D. Gadžo, T. Šarić, T. Gavrić, Š. Muminović: 

Investigation of allelopathic potential of buckwheat.......................... 59 

8. M. Knežević, B. Stipešević, Lj. Ranogajec, I. Knežević: Long-term 

effects of soil tillage on weed populations in winter wheat ………... 73 

9. S. Maneva, S. Deneva Milanova: Possibilities of reduced doses of 

post-emergent herbicides: preliminary results……………………… 87 

10. Ts. Dimitrova, P. Marinov-Serafimov: Chemical weed control 

in stands of red clover: (Trifolium repens L.) in the year of their 

establishment……………………………………………………….. 95 

Instruction to Authors in Herbologia………………………………… 101

Herbologia Vol. 9, No. 2, 2008. 

CIRSIUM ARVENSE (L.) Scop. COMPETITION WITH WINTER 

WHEAT 

Ralitsa Nakova 

Plant Protection Institute, 2230 Kostinbrod, Bulgaria 

ralitsa_n@abv.bg 

Abstract 

Field experiment was conducted in the Plant Protection Institute, 

Kostinbrod, Bulgaria to evaluate the competitive effect of Cirsium 

arvense density on wheat yield and its components. Treatments consisted 

of five C. arvense densities (D 1 0, D 2 2, D 3 4, D 4 6, D 5 8 plants/m 2 ). The 

data were recorded on wheat: density m -2 , plant height, spike length, 

spikelets spike -1 , number of grains spike -1 , grain weight spike -1 ,1000 

grain weight. The effect on wheat grain yield was established. Increased 

weed density decreased wheat yield and its components. Regression 

analysis of the data showed that all wheat studied parameters were 

significantly negatively affected by C .arvense densities. The major yield 

component influenced by C. arvense competition was wheat density per 

unit area, with grain weight spike -1 . Grain yield losses of approximately 

30% are expected in patches with 8 C .arvense shoots m -2 . The 

relationship between C. arvense density and wheat yield and its 

components was dependent of weed density, inter-specific competition 

and weather in the year. The coefficients of determination (R 2 ) were very 

high, ranging from 0.89 to 1. The regression models give grain yield loss 

estimates at commonly occurring shoot density of C. arvense and may 

have practical application by predicting wheat yield in crop production 

systems. 

Keywords: wheat, C. arvense (L.) Scop, grain yield, yield components, density, 

regression models 

Introduction 

C. arvense is recognized as a very competitive perennial weed in 

cereals in Bulgaria and causes large economic losses in these crops. On 

average C.arvense occurred in approximately 40% of all winter wheat 

fields in Bulgaria. The competitive effect of this weed on wheat has not 

document in Bulgaria. In the contemporary investigations the effect of 

weed density was studied in the many weeds. Walia and Manpreet (2005) 

have studied the effect of increasing densities of Avena ludoviciana L.(0,


1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80 and 100 plants/m 2 ) and 

Rumex spinosos L. population (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25 

and 30 plants/m 2 ) on wheat yield. Grain yield decreased with increasing 

weeds intensity. The effects of Avena fatua L.(0, 5, 10, 15, 20, 25, 30 

seeds m -2 ) on wheat yield and its components are evaluate. Most of the 

parameters were significantly affected by wild oat density. The greatest 

number of spike m -2 (282), spike length (9.3 cm), number of grains per 

spike (50), and 1000 grain weight (30.26) were recorded for wheat 

monoculture (no wild oat plant) (Khan and Hassan, 2006). The density of 

wheat decreased with the increase in wild oat density. Only 150 wheat 

plants/m -2 were recorded under a wild oat density of 50 plants/m -2 , 

compared to 262 plants/m -2 in wheat monoculture. The height of wheat 

plants was also affected by more than 50% at the highest density of wild 

oats (Hassan and Yousafzai, 2006). An increase in Avena fatua L. and 

Papaver rhoeas L. density of 5 to 30 plants/m -2 decrease the wheat 

growth parameters and yield (Nakova, 2003 a , 2003 b ). In a competitive 

situation the density of Galium aparine L. is a major factor governing 

growth, development and grain yield of wheat. The period of weed 

competition begin in level of G. aparine L.- 15 plants/m 2 . An increase 

clever density from 15 to 25 plants/m 2 , significantly decreased the level 

of height, fresh weight, dry weight, leaf area of wheat plants and also 

wheat grain yield. The study show strategies for weed control in wheat 

using thresholds based on weed density (Nakova, 2007). Wheat yield and 

percentage loss varied depending on density of mayweed 

(Tripleurospermum inodorum L.). Wheat yield reduction was 18, 21, 

35% for mayweed densities of 20, 40, 60 plants/m -2 , respectively. 

Increasing weed density decreased weight of 1000 grains from 51 to 44 g 

and volumetric grain weight from 78 to 68 kg/hl (Ionescu, 2007). Maneva 

(2007) investigated the competitive relationship between wheat and two 

weed species, Viola arvensis L. in densities of (0, 1, 3, 5, 6, 7, 8, 9, 10, 

14, 15, 16, 19, 22, 25, 27, 36, 40, 44, 47, 55, 60, 71, 75, 77 plants per m -2 

) and Delphinium consolida L.in densities of ( 0, 1, 2, 3, 8, 10, 15, 19, 21, 

29, 32, 33, 25, 40, 42, 48, 50, 51, 58, 64, 72, 96 plants per m 2 ) in field 

condition. The reduction of the all observed morphological parameters of 

the productiveness (MMP) – wheat spike m -2 , wheat spike length, 

spikelest spike -1 , number of grains spike, grain weight spike -1 and grain 

yield, presented as an Index of depression (ID) was stronger for the V. 

arvensis L .than for D. consolida L. The wheat spike m -2 showed the 

stronger decreasing (45% of the respective control) for both weed 

species. Increasing the weed density of D. consolida L. could reduce the 

grain weight spike -1 with 45%. The number of spikelest spike -1 was the 

2

Cirsium arvense (L) Scop. competition with winter wheat 

less affected of the weed competition (nearly 4 and 25%) for D. 

consolida L .and V. arvensis L., respectively. Amini et al. (2005) 

established competition between wheat and Secale cereale L. The 

morphological productive parameters decreased with increase in weed 

intensity. Multispecies competition effects of weeds (Chenopodium 

album L., Stelaria holostema L., Fumaria spp., Poligonum aviculare L., 

Convolvulus spp. on wheat was determined (Ghanbari et al., 2005, 

Masaheri et al,. 2005). Authors found the effects of vary density in the 

term of wheat grain yield. Wheat yield components were considered as a 

index for effect of weed competition on wheat grain yield. The studies of 

Stoimenova and Alexieva (2003) and Serafimov (2005) showed 

predicting yield loss using weed density data or weed dry biomass. 

The aim of the study was to evaluate the competitive effect of C. 

arvense density on wheat grain yield and its components. 

Material and methods 

Field study was conducted at Plant Protection Institute, Kostinbrod 

during 2006-2007 on fine sandy loam soil. The experimental design was 

a randomized complete block with four replicates. Treatments consisted 

of five C. arvense densities ( D 1 0, D 2 2, D 3 4, D 4 6, D 5 8 plants/m 2 ). Plot 

size was 10 m 2 (1m wide x 10m length). Seeds of C. arvense was not 

planted as there were sufficient natural soil reserves of seed of this 

species. The seed of Sadovo 1 wheat variety were sown at 200 kg/ha in 

October 2006. All the recommended cultural practices were carried out 

uniformly in all treatments during the experiment expect for variables 

intended for studies. The number m 2 of C. arvense plants for each variant 

present at harvest were determined. All other weeds were removed 

manually through the wheat season on weekly basis. Nitrogen fertilizer 

was applied to the plots in the spring of 2007. The conventional fertilizer 

was ammonium nitrate, which was applied at the rate 200 kg/ha -1 . The 

experiment was harvested in the late July 2007. 

3


Table 1. Weather data on experimental site during 2006-2007 

Total 

Maximum Minimum 

Month/Year 

rainfall 

temperature temperature 

(mm) 

(average) (average) 

November, 2006 

December, 2006 

January, 2007 

February, 2007 

March, 2007 

April, 2007 

May, 2007 

June, 2007 

July, 2007 

18.8 

7.9 

18.7 

17.0 

19.8 

24.5 

30.2 

30.6 

32.0 

Average: 22.1 

-8.0 

-2.8 

-9.3 

-9.4 

-6.1 

-3.4 

2.2 

7.1 

6.4 

Average: -6.0 

10 

16 

19 

27 

21 

11 

150 

37 

7 

Total: 298 

The data were recorded on wheat: density m -2 , wheat plant height, 

wheat spike length, spikelets spike -1 , number of grains spike -1 , grain 

weight spike -1 , 1000 grain weight. These yield components were 

determined on 100 wheat plants from every repetition in all treatments. 

Grain yield (kg/ha) by variants and replication was established. 

Linear regression analysis of data was done using Microsoft Exel. 

The interdependence between the densities of C. arvense, grain yield and 

its studied components was summarized by the coefficient of 

determination (R 2 ). The regression models was characterized by the 

equation y= bx+a, where y is the studied parameters, b is the 

proportionality (regression coefficient), a is the initial value of y at x=0. 

The regression line graphically depicts the relations. 

Results and discussion 

The data (Table 1) showed that the weather data (temperature and 

precipitation) of experimental site have negatively effect on wheat grain 

yield. The weather during infestation period was cold and dry. This 

significant increased adverse effects of C. arvense on wheat yield and its 

components. However the negatively influence of yield losses were 

density dependent. 

The data (Table 2) exhibit that mean wheat density of 253, 226, and 

205 numbers/m -2 were obtained for the 0, 4 and 8 weed densities, 

respectively. Between the densities, maximum wheat plant height was 

4


establishes (60 cm) in 0 plants/m 2 (control variant), while minimum (55 

cm) was recorded in 8 plants C .arvense m -2 . The results from effect of 

different densities on spike length were unidirectional with these 

presented for wheat height. The yield components spikelets spike -1 and 

number of grains spike -1 were significantly affected at highest weed 

density. Results showed that C. arvense densities m -2 from 2 to 8 have 

strong negative effect on grain weight spike -1 . The reduction was from 

0.2 to 0.7 g for 2 and 8 weed population, respectively. 1000 grain weight 

was also decreased by increasing weed density. The reduction in wheat 

yield components closely paralleled the reduction in grain yield. Data 

exhibit that for the C .arvense densities wheat grain yield was highest at 

0 weed plants/m 2 and least at 8 C. arvense plants/m -2 . The coefficients of 

determination (R 2 ) between weed density and wheat grain yield and its 

components were very high, ranging from 0.89 to 1 (Fig. 1). 

Variants 

( Densities 

C.arvense 

plants/m 2 ) 

Table 2. Effect of C. arvense density on wheat yield and its components 

Wheat 

density 

m -2 

Wheat 

plant 

height, 

cm 

Wheat 

spike 

length, 

cm 

Number 

of 

grains 

spike -1 

Spikelets 

spike -1 

Grain 

weight 

spike -1 , 

g 

1000- 

grain 

weight, 

g 

Grain 

yield, 

kg/ha -1 

0 253 60 6.1 7 40 1.3 40.6 1830 

2 245 59 5.9 7 39 1.1 40.1 1720 

4 226 58 5.8 6 38 0.8 38.5 1690 

6 221 56 5.0 6 37 0.7 37.9 1500 

8 205 55 4.8 5 36 0.6 37.0 1300 

Wheat density, m -2 

300 

250 

200 

150 

100 

50 

0 

y = -6x + 254 

R 2 = 0.9756 

0 2 4 6 8 10 

Wheat plant height, cm 

65 

60 

55 

50 

y = -0.65x + 60.2 

R 2 = 0.9826 

0 2 4 6 8 10 

Density of C.arvense (plants/m -2 ) 


5


Wfeat spike lenght,cm 

9 

6 

3 

0 

y = -0.175x + 6.22 

R 2 = 0.9088 

0 2 4 6 8 10 

Spikelets spike-1 

8 

6 

4 

2 

0 

y = -0.25x + 7.2 

R 2 = 0.8929 

0 2 4 6 8 10 



Number of grains spike -1 

42 

40 

38 

36 

34 

y = -0.5x + 40 

R 2 = 1 

0 2 4 6 8 10 


Grain weight (g) spike -1 

1,5 

1 

0,5 

0 

y = -0.09x + 1.26 

R 2 = 0.9529 

0 2 4 6 8 10 

Density of C.arvens e(plants/m -2 ) 

1000 grain weight,g 

42 

40 

38 

36 

y = -0.47x + 40.7 

R 2 = 0.9744 

0 2 4 6 8 10 

Grain yield (kg/ha -1 ) 

2000 

1600 

1200 

800 

400 

0 

y = -64x + 1864 

R 2 = 0.9358 

0 2 4 6 8 10 



Fig.1 Relationship between C.arvense density and wheat yield and its 

components 

Analysis of data indicated that C.arvense has a strong competitive 

effect on wheat. Increasing the proportion of weed plant wheat density 

decrease. The magnitude of wheat density losses were C.arvense density 

depend. The reason could be the higher inter-specific competition among 

two species, which started early at higher weed densities. These results 

were strongly supported by Donald and Khan (1996). They reported that 

increasing Canada thistle density decreased wheat density. Canada thistle 

also reduced spikes plant -1 and seed spike -1 to varying extends depending 

on year. Wheat plant height and spike length at maturity were also 

6


affected from weed densities. Increasing C.arvense density decreased 

values of these studied parameters. The reduction of the yield 

components- spikelets spike -1 and number of grains spike -1 resulted in the 

reduction of grain yield. Grain weight spike -1 was significantly affected 

by C.arvense density. Our results depict that weight was directly 

proportional to the weed density. Under the lesser densities of weed the 

wheat was able to make better use of soil and environmental resources, 

resulting in bolder grains. Analysis of data showed that grain yield of 

wheat was negatively affected by increasing C.arvense densities. Various 

yield reduction in wheat due to C.arvense competition have been 

reported in the literature. Reported yield losses range from 1-61%, 

corresponding to C.arvense densities of 2–30 shoots m -2 (Hogson, 1968, 

Peschken et al., 1980). 

Regression analysis of data showed that wheat grain yield and its 

components were linearly affected by C.arvense densities. The 

regression models accurately and realistically describe the percentage 

reduction in wheat yield and its components. These data indicate that the 

type of model proposed by Cousens (1985) can by extended to indicate 

competition between crops and perennial weeds under dry conditions. 

The effect of C.arvense density on wheat density, plant height, spike 

length, spikelests spike, number of grains spike, grain weight spike, 1000 

grain weight and grain yield was predicted by the equations. Our 

conclusions are in line with the work of O` Sullivan et al. (1982), who 

have confirmed that yield losses of 18 to 52% were predicted from 

C.arvense shoots densities of 5 to 45 shoots m -2 , respectively. The 

regression lines show the dependence on studied parameters when there 

is no influence of another factors. The observed values for the studied 

variables fit regression line very closely or in some instance exactly. The 

slopes indicated that increasing weed density, decreased the grain yield 

and its components, which showed that inter-specific competition was 

established. The regression models may have practical application, such 

as prediction of wheat grain yield in crop production systems in an 

integrated weed management program. 

Thus it can be concluded from the results that C.arvense competition 

reduced wheat grain yield, primarily through a reduction in the wheat 

density (number spikes per unit area) and grain weight spike -1 . In areas 

where C.arvense is abundant, it represents a serious impediment to wheat 

production. 

7


References 

AMINI, R., F. SHARI., M. BAGASTANI., D. MAZAHERI., A. ATRI, 

(2005):Investigation on competition between weed and Secale cereale. 13 th 

EWRS Symposium, Bari, Italy, on CD. 

COUSENS, R, (1985): A simple model relating yield loss to weed density. Annals of 

Applied Biology, 107: 239-252. 

DONALD, W., M. KHAN, (1996): Canada thistle (Cirsium arvense) effects on yield 

components of spring wheat( Triticum aestivum). Weed Science, 44, 1:114- 

121. 

GANBARI, A., D. MAZAHERI., M. GHANNADHA., J. GHEREKHLOO, (2005): 

Evaluations of multispecies weed competition in wheat. 13 th EWRS 

Symposium, Bari, Italy, on CD. 

HASSAN, G., H.YOUSAFZAI, (2006): Effect of wild oat (A.fatua) density on wheat 

yield and its components under various nitrogen regimes. Herbologia, 7, 2: 71- 

83. 

HOGSON, J, (1968): The Nature, Ecology and Control of Canada Thistle. US 

Departament of Agriculture Technical Bulletin, №6, 1386: pp32. 

IONESCU, N, (2007): Influence of emergence time and density of mayweed 

(Tripleurospermum inodorum Sch (Bip) on winter wheat (Triticum aestivum 

L.). 14 th EWRS Sym posium Hamar, Horway: pp.95. 

KHAN, M., G. HASSAN, (2006): Effect of wild oats (A.fatua) densities and 

pproportions on yield and yield components of wheat. Pakistan Journal of 

Weed Science Research 12, ½: 69-77. 

MANEVA, S, (2007): Doktoral thesis, Kostinbrod: p. 170-172. 

MASAHERI, D., J. GHEREKHLOO., A. GHANBARI., M. GHANNADHA, (2005): 

Multispecies competition effects of weeds on wheat. 13 th EWRS Symposium, 

Bari, Italy, on CD. 

NAKOVA, R, (2003 a ): Study of the competition between wheat and Avena fatua L. 

Bulgarian Journal of Agricultural Science, 9: 335-338. 

NAKOVA, R (2003 b ): Study of the competition between wheat and Papaver rhoeas L. 

7 th Mediterranean Symposium EWRS. Adana, Turkey: 125-126. 

NAKOVA, R, (2007): Investigation on competition betwee wheat and Galium aparine 

L. Plant Science, 44,: 217-221. 

O` SULLIVAN, P., V. KOSSATZ., G. WEISS., P. DEW, (1982):An approach to 

estimate yield loss of barleydue to Canada thistle. Canadian Journal of Plant 

Science, 62: 725- 731. 

PESHKEN, D., J. HUNTER., A. THOMAS, (1980): Damage in dollars caused by 

Canada thistle in wheat in Saskatchewan. Procceding of the Canada Thistle 

Symposium, Agriculture Canada, Regina: pp 34-43. 

SERAFIMOV, P, (2005): Doctoral thesis, Plovdiv: p. 159-164. 

STOIMENOVA, I., S. ALEXIEVA, (2003): Predicting yield loss due to investigation to 

from weed flora usin weed density data or weed dry biomass. 7 th Mediterranean 

Symposium EWRS. Adana, Turkey: 135-136. 

WALIA, U., S. MANPRET, (2003): Studies on the threshold values of Avena 

ludoviciana L. and Rumex Spinosus L.in wheat. Indian Journal of Weed 

Science, 37, ½ :91-92. 

8


THE SUMMER ASPECT OF WEED FLORA IN THE VINEYARDS 

OF HERZEGOVINA 

Zlatan Kovačević, Faculty of Agriculture, University in Banja Luka, 

Danijela Petrović, Nevenko Herceg, Faculty of Agriculture, University in 

Mostar 

e-mail: danijelapetrovic@net.hr 

Abstract 

The paper presents the review of weed flora in the Herzegovina 

vineyard region in the summer aspect. The researched area includes the 

following municipalities: Trebinje, Stolac, Počitelj, Mostar, Čitluk, 

Grude, Široki Brijeg, and Ljubuški. The flora was studied from the 

aspects of taxonomic diversity, biological spectrum and the spectrum of 

areal types. During the floristic research, 69 weed species were 

registered. By the taxonomic analysis, it was established that all 

registered weed species belonged to the section of Spermatophyta (59 

species belong to the class Magnoliate and 10 species to the class 

Liliate). The flora is distributed in 28 families. The biological spectrum 

of weed flora has outstanding therophyto-hemicryptophytic character (56 

species or 81.2%). By the phytogeographycal analysis, domination of the 

species from the group of floral elements with wide area of spreading 

was registered (euroasian, circumpolar and cosmopolitan, adventive and 

pontic-centralasian). This group includes 52 plant species or 75.4%. 

Keywords: weed flora, life forms, floral elements. 

Introduction 

In 1984, areas under grapevine in Socialist Federative Republic of 

Yugoslavia (SFRJ) were around 238.000 ha, so it took the 7th place in 

Europe and 11th place in the World. Socialistic Republic (SR) Bosnia 

and Herzegovina participated with about 5.367 ha (Avramov, 1991). The 

largest part of these areas is located in Herzegovina, where production 

and processing of grape have has long lasting tradition (Lučić et al., 

1997). In the frames of Bosnia and Herzegovina (B&H), districting of 

viticulture of ex Yugoslavia has defined two vineyard regions: 

Herzegovina region and the north Bosnia region. In the frame of 

Herzegovina region, subregion of central Neretva and Trebišnjica has

Z. Kovačević et al. 

been defined and within this subregion Mostar vineyard region (Tarailo, 

2001). 

Vineyards are perennial agrophytocenosis where cultivated plant 

(grapevine) is agroedificator. Its edificators' role is expressed only under 

the human influence, so it can’t perform edificators' function in natural 

plant associations (Čanak and Parabućski Stanija, 1976). As all 

agroecosystems, vineyards are unstable creations. Weeds regularly 

appear as factors of vineyards agrophytocenosis. They enter in 

competitive relationships with agroedificator, causing blight. Grapevine 

is very sensitive on harmful influence of weeds in the period of vineyard 

establishment, as well as in later period, during vineyard exploitation 

(Kojić and Šinžar, 1985). 

Research of weed flora in B&H are very poor. Significant 

contribution in recognizing of this problem was presented in papers 

Šumatić, 1997 and Kojić et al., 2005. There have been no research of 

vineyards weed flora and vegetation in B&H till now. Nevertheless, 

certain number of authors gave significant contribution to understanding 

the characteristics of weed sinuous in vineyards. On the one side, those 

papers concern the state and perspective of viticulture and general 

questiones about characteristics of weed sinuous in vineyards (Čanak and 

Parabućski Stanija, 1976, Lučić et al., 1997, Tarailo, 2001). On the other 

side, floristic-phytocenotic researches of vineyards have been performed, 

frequently connected with seasonal dynamics of weed sinuous 

(Živanović, 1988, Crnčević et al., 1992, Šinžar and Živanović, 1976, 

1992, 1993, Živanović, 1988, Živanović et al., 1999, Stanković et al. 

1976, Anđelić, 1976, Grković, 1987, Hulina, 1979, Parabućski and 

Čanak, 1973, Šefik, 1983, Komić, 1983). 

The paper presents the review of weed species in Herzegovina 

region in summer aspect, with detailed taxonomic analysis, biological 

spectrum and phytogeographical analysis. 


The floristic research was performed in summer aspect in 2006, in 

vineyard region of Herzegovina, which includes the following 

communities: Trebinje, Stolac, Počitelj, Mostar, Čitluk, Grude, Široki 

Brijeg and Ljubuški. 

Plant material was determined according to the papers: Flora SR 

Srbije I-IX (Josifović i dr., 1970-1977), Flora Hrvatske (Domac, 1994), 

Flora Italiana (Fiori, 1921) and Ikonographie der Flora des Südöstlichen 

Mitteleuropa (Javorka, 1979). 

10

The summer aspect of weed flora in the vineyards of Herzegovina 

Taxonomy and nomenclature are given according to publication Flora 

Europaea 1-5 (Tutin, T. G. ed., 1964-1980). 

As part of analytic phase, floristic analysis of the defined taxons 

includes: analysis of life forms and analysis of floral elements. 

Life forms of plants are given according to Kojić and others 

(1994). Floral elements are given according to Gajić (1980). 


During the floristic research of weed flora in vineyard region 

Herzegovina, 69 species have been registered and determined in summer 

aspect. Table 1. shows the review, biological spectrum and the spectrum 

of areal types of registered weed species. 

Table 1. The summer aspect of weed flora in the vineyards of 

Herzegovina. 

Weed species 

Life 

form 

Floral element 

Allium vineale L. g Centraleuropean 

Amaranthus retroflexus L. t Adventive 

Anthemis arvensis L. t Subcentraleuropean 

Aristolochia clematitis L. g Submediterranean 

Avena barbata Pott. ex 

Link. 

t Adventive 

Berteroa mutabilis (Vent.) 

DC. 

th Subpontic-centralasian 

Bilderdykia convolvulus (L.) 

Dumort. 

t Subeuroasian 

Chenopodium album L. t Cosmopolitan 

Chenopodium polyspermum 

L. 

t Euroasian 

Chondrilla juncea L. 

h 

Pontic-centralasiansubmediterranean 

Cichorium intybus L. h Subeuroasian 

Cirsium arvense (L.) Scop. g Subeuroasian 

Clematis flammula L. np Submediterranean 

Consolida regalis S.F.Gray t Subcentraleuropean 

Convolvulus arvensis L. g Cosmopolitan 

11


Lepidium draba L. 

h 

Conyza canadensis (L.) 

Cronq. 

th Adventive 

Crepis sancta (L.) Babcock h Submediterranean 

Cynodon dactylon (L.) Pers. g Cosmopolitan 

Dactylis glomerata L. h Subeuroasian 

Datura stramonium L. t Cosmopolitan 

Daucus carota L. th Subeuroasian 

Digitaria sanguinalis (L.) 

Scop. 

t Cosmopolitan 

Diplotaxis muralis (L.) DC. th Submediterranean 

Echinochloa crus-galli (L.) 

Beauv. 

t Cosmopolitan 

Echium italicum L. th Submediterranean 

Erigeron annuus (L.) Pers. th Adventive 

Euphorbia chamaesyce L. t 

Ponticsubmediterranean 

Euphorbia helioscopia L. t Subeuroasian 

Foeniculum vulgare Mill. h Adventive 

Galinsoga parviflora Cav. t Adventive 

Geranium molle L. th Subeuroasian 

Gypsophyla muralis L. t Euroasian 

Hibiscus trionum L. t 

Ponticeastensubmediterranean 

Kickxia spuria (L.) Dum. t 

Subatlanticsubmediterranean 

Lactuca saligna L. th 

Subponticsubmediterranean 

Lathyrus tuberosus L. g Subsouthsiberian 


Linaria vulgaris Mill. h Subcentraleuropean 

Marrubium vulgare L. h Subeuroasian 

Medicago lupulina L. th Subeuroasian 

Mentha arvensis L. g Circumpolar 

Mentha longifolia (L.) 

g 

Subcentraleuropean 

Huds. 

Oxalis stricta L. h Adventive 

Papaver rhoeas L. th Subeuroasian 

12


Thlaspi arvense L. th Subevr. 

Petrorhagia saxifraga (L.) 

Link. 

zc Submediterranean 

Phleum pratense L. h Subeuroasian 

Plantago major L. h Euroasian 

Polygonum aviculare L. t Cosmopolitan 

Polygonum lapathifolium L. t Subcircumpolar 

Portulaca oleracea L. t Cosmopolitan 

Potentilla reptans L. h Euroasian 

Raphanus raphanistrum L. t Subcentraleuropean 

Reseda lutea L. th Subcentraleuropean 

Rorippa sylvestris (L.) Bess. h Subeuroasian 

Rosa canina L. np Subcentraleuropean 

Rubus ulmifolius Schott. np 


Rumex crispus L. h Euroasian 

Satureja montana L. h Submediterranean 

Senecio vulgaris L. th Euroasian 

Setaria glauca (L.) Beauv. t Cosmopolitan 

Setaria viridis (L.) Beauv. t Subeuroasian 

Solanum nigrum L. t Cosmopolitan 

Sonchus oleraceus L. th Subeuroasian 

Sorgum halepense (L.) Pers. g Cosmopolitan 

Taraxacum officinale 

Weber 

h Euroasian 

Tribulus terrestris L. t 


Verbena officinalis L. th Cosmopolitan 

Xanthium italicum Moretti t Adventive 

In the vineyards of Fruška Gora region, Šinžar and Živanović 

(1992) registered 74 plant species. In the vineyards of Vršac, Anđelić 

(1976) registered 46 weed species. On the south slopes of Fruška Gora, 

Crnčević et al. (1992) registered 66 weed species in summer aspect. 

Živanović (1988) concluded that summer aspect of weed flora in 

the vineyards of Belgrade surroundings is the most abundant by flora, 

with dominated weed species which are characteristic for annual row 

crops. During the research of seasonal dynamics of weed sinuous in 

13


vineyards, he noticed the significant differences in presence of weed 

sinuous in certain microhabitats. Weed sinuous in summer aspect is 

quantitatively and qualitatively the most expressed. It includes 35 species 

(from the total 53 species in all three aspects) with 10 species presented 

in microhabitat of order, and 9 species in microhabitat between orders. 

On the basis of results obtained by the research of seasonal 

changes in floristic composititon and structure of weed sinuous in the 

vineyards of the south part of fruit and grape growing region of Fruška 

Gora, Crnčević et al. (1992) concluded that summer aspect is consisted of 

66 weed species. Among them are the most significant late summer and 

perrenial weeds. 

Taxonomic analysis (Table 2.) shows that all registered weed 

species belong to section Spermatophyta, 59 species belong to class 

Magnoliate and 10 species to class Liliate. The flora is distributed in 28 

families. The most abundant with species are families: Asteraceae, 

Poaceae, Brassicaceae, Lamiaceae and Polygonaceae, presented with 37 

species or 53.6%. 15 families are presented with one species. Species 

which belong to family Poaceae have a great importance as vineyard 

weeds, because of intensive vegetative reproduction and fast 

regeneration. According to that, they represent the most significant 

vineyard weeds. 

Table 2. Taxonomic analysis of weed flora in the vineyards of 

Herzegovina. 

Species 

Section Class Family numbe % 

r 

Spermatophyt 

Asteraceae 13 18.8 

a 

Brassicaceae 7 10.0 

(69 species) Magnoliate Lamiaceae 4 5.7 

(59 species or Polygonaceae 4 5.7 

85.5%) 

Rosaceae 3 4.3 

Fabaceae 2 2.9 

Apiaceae 2 2.9 

Caryophyllacea 

e 

2 2.9 

Chenopodiacea 

e 

2 2.9 

Euphorbiaceae 2 2.9 

14


Liliate 

(10 species or 

14.5%) 

Ranunculaceae 2 2.9 

Scrophulariace 

ae 

2 2.9 

Amaranthaceae 1 1.5 

Aristolochiacea 

e 

1 1.5 

Boraginaceae 1 1.5 

Convolvulaceae 1 1.5 

Geraniaceae 1 1.5 

Malvaceae 1 1.5 

Oxalidaceae 1 1.5 

Papaveraceae 1 1.5 

Plantaginaceae 1 1.5 

Portulacaceae 1 1.5 

Resedaceae 1 1.5 

Solanaceae 1 1.5 

Verbenaceae 1 1.5 

Zygophyllaceae 1 1.5 

Poaceae 9 13.0 

Liliaceae 

1 1.5 

Total 69 100 

Biological spectrum of weed flora in Herzegovina vineyard 

region (Table 3.) is in corelation with habitat conditions. It has 

outstanding therophyto-hemicryptophytic character, because 56 species 

(or 81.2%) belong to therophytas, hemicryptophytas and 

therohemocryptophytas, while the participation of other life forms is 

significantly lower. From practical aspect, it is important to emphasize 

that in biological spectrum significant part belongs to geophytas (9 

species or 13%), which have very intensive vegetative reproduction. 

During the research of weed flora and vegetation in orchards of 

B&H, Kojić et al. (2005) concluded that hemicryptophytas dominate in 

biological spectrum (40.7%), which they connect with low application 

level of agrotechnic and other measures of care. That represents a 

significant difference comparing to biological spectrum of weed flora in 

Herzegovina vineyards region. 

During the research of weed sinuous in the vineyard of fruite and 

grape growing region of Fruška Gora, in Sremski Karlovci, Šinžar and 

Živanović (1976) concluded that therophytas are the most presented in 

15


biological spectrum of summer aspect, while geophytas and 

hemicryptophytas participate with 32.7%. In the frame of species of 

characteristic collection, participation of therophytas reduces to 53.3%, 

while participation of geophytas (20,00%) and hemicryptophytas 

(26,67%) increases. This fact shows that perrenial weeds have a very 

significant role in establishment of weed association in vineyards. The 

same authors state that participation of weed – ruderal plants increases 

from 59.2% to 65.2% and participation of segetal reduces from 31.6% to 

23.9% during autumn aspect in comparison to summer. 

Table 3. Biological spectrum of weed flora in the vineyards of 

Herzegovina. 

Life form 

Number of 

species 

(%) 

t 25 36.2 

th 16 23.2 

h 15 21.7 

g 9 13.0 

np 3 4.4 

zc 1 1.5 

Total 69 100 

Specificity of areal types analysis of weed flora in Herzegovina 

vineyard region is reflecting in quantitative participation of geoelements 

(Table 4.). First impression is getting by the conclusion that 15 floral 

elements are determined by phytogeographic analysis. Domination of 

species from the group of floral elements with wide area of spreading is 

outstanding (euroasian, circumpolar and cosmopolitan, adventive and 

pontic-centralasian). This group includes 52 plant species or 75.4%, what 

is in accordance with cosmopolitism of weed flora. The group of floral 

elements with narrow area of spreading (centraleuropean, 

submediterranean and atlantic) is significantly poor by flora (17 species 

or 24.6%). The most abundant with species are: subeuroasian, 

cosmopolitan, subcentraleuropean, euroasian and adventive floral 

elements. 

16


Table 4. The spectrum of floral elements of weed flora in the vineyards 

of Herzegovina. 

Group of floral elements 

Euroasian 

(23 species or 33.3%) 

Floral element 

Number 

of % 

species 

Subeuroasian 15 21.7 

Euroasian 7 10.2 

Subsouthsiberian 1 1.5 

Cosmopolitan 12 17.4 

Circumpolar 1 1.4 

Circumpolar and 

cosmopolitan 

(14 species or 20.3%) Subcirkumpolar 1 1.4 

Centraleuropean 

Subcentraleuropean 7 10.2 

(8 species or 11.6%) Centraleuropean 1 1.5 

Adventive 


Adventive 8 11.6 


3 4.3 

Subponticsubmediterranean 

Pontic-Centralasian 

2 2.9 


Ponticeasternsubmediterranean 

1 1.5 

Subpontic-centralasian 1 1.5 

Submediterranean 


Submediterranean 7 10.2 

Atlantic 



2 2.9 

Total 69 100 

During the research of the flora and vegetation of orchards in 

B&H, Kojić et al. (2005) registered 16 floral elements. With domination 

of euroasian group, they emphasized a large presence of 

submediterranean floral element (14.6%)in Herzegovina, which isn´t case 

in flora of Herzegovina vineyard region where submediterranean floral 

element is presented with 7 weed species (10.1%). That is connecting 

with different application level of agrotechnic measures in vineyard and 

orchard. 

17


Conclusions 

During the floristic research of weed flora in Herzegovina 

vineyard region, 69 taxons have been registered. 

Taxonomic analysis shows that all registered weed species belong 

to section Spermatophyta (59 species belong to class Magnoliate and 10 

species to class Liliate). Registered species are distributed in 28 families. 

Among these, the more abundant by flora are the following families: 

Asteraceae, Poaceae, Brassicaceae, Lamiaceae and Polygonaceae, 

which together include 37 species or 53.6%. 

Biological spectrum of weed flora has outstanding therophytohemicryptophytic 

character, because 56 species (81.2%) belong to 

therophytas, hemicryptophytas and therohemocryptophytas. 

By phytogeographical analysis, 15 floral elements have been registered, 

with domination of species which belong to the group of floral elements 

with wide area of spreading (euroasian, circumpolar and cosmopolitan, 

adventive and pontic-centralasian). This group includes 52 plant species 

or 75.4%, while the group of floral elements with narrow area of 

spreading (centraleuropean, submediterranean and atlantic) is 

significantly poor by flora (17 species or 24.6%). 

The data about floristic structure, biological spectrum and 

seasonal dynamics of weed sinuous of vineyard agrophytocenosis should 

be the basis for planning of weed control measures, especially chemical, 

because of proper choise of herbicides and their spectrum of influence. 

Special attention should be paid to perrenial weeds because of large 

reproducting and regeneration power, as well as rezistance toward 

herbicides. 

References 

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FIORI, A. (1921): FLORA ITALIANA. SANCASCIANO VAL DI PESA, STAB. 

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(1/2), str. 277-287, Zagreb. 

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Medvednice. Proc. ekol. kongres, str. 527-535, Zadar-Plitvice. 

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Bosne i Hercegovine. Naučno voćarsko društvo Republike Srpske, Banjaluka. 

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suzbijanje herbicidima. Zbornik Saveza društva za zaštitu bilja Jugoslavije, 5, 

str. 381-387, Beograd. 

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vinograda i položaj vinograda među antropogenim zajednicama. Ekologija, D, 

6 (1), str. 53-61. 

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terenima severne Bačke. Zbornik radova Jugoslovenskog simpozijuma o borbi 

protiv korova u voćnjacima i vinogradima, str. 89-102, Peć. 

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mogućnosti eliminisanja korova uz aplikaciju herbicida. Magistarski rad, 

Poljoprivrednii fakultet, Osijek. 

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okoline Sremskih Karlovaca. Zbornik radova Jugoslovenskog simpozijuma o 

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19


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agrofitocenoza vinograda okoline Beograda. Zbornik referata Trećeg kongresa 

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519-523, Beograd. 

20


DISTRIBUTION OF WEED FLORA IN CHICKPEA CROP IN 

DISTRICT DERA ISMAIL KHAN, PAKISTAN 

Gul Hassan 1 , Imtiaz Khan 1 and Naqibullah Khan 2 

1 Department of Weed Science, NWFP Agricultural University, Peshawar, 

Pakistan 

E-mail:hassanpk_2000pk@yahoo.com 

2 

Department of Plant Breeding and Genetics, NWFP Agricultural University, 

Peshawar, Pakistan 

Abstract 

Five locations, mainly from the rice based cropping system of Dera 

Ismail Khan, were randomly selected to decipher the flora infesting Cicer 

arietinum crop during winter 2005. The computation of importance value is a 

good judgment for deciding the status of a given weed in a community. 

Based on spatial data it is concluded that Lathyrus aphaca, Lathyrus sativus, 

Melilotus indica, Convolvulus arvensis, Medicago denticulate, and Rumex 

crispus as the important weeds of Dera Ismail Khan, in the descending order. 

Up to 80% losses were caused by Lathyrus aphaca L. and L. sativus in 

chickpea fields in Dera Ismail Khan. As far as the management implications 

of these weeds are concerned, their manual as well as chemical management 

tactics are threatened by their morphological and physiological resemblance 

with the chickpea. 

Keywords: chickpea weeds, Dera Ismail Khan, Weed distribution, Importance value 

Introduction 

Dera Ismail Khan is the bread basket of North West Frontier 

Province (NWFP). Dera Ismail Khan is bounded on north by District 

Lakki Marwat, Dera Ghazi Khan onto south, Tank in the west and river 

Indus into the east. Dera Ismail Khan has the largest cultivable area in 

whole of NWFP. The rice based cropping system as in turn offered in an 

impetus to grow chickpea on the residual moisture of rice. Chickpea is 

also grown in rain-fed conditions. But, the chickpea production is 

altogether a different culture from the Lakki Marwat and Karak District 

(Khan et al. 2005; Hassan and Khan, 2007). The soils of Dera Ismail 

Khan are mostly not sandy rather ranging from silty through silty loam to 

clayey. As the edaphic conditions differ from the preceding Districts so is 

the variability in the flora infesting chickpea crop. The major cropping 

patterns of Dera Ismail Khan are Rice-chickpea-rice, sugarcane-

G. Hassan et al. 

sugarcane-wheat, wheat-rice-wheat and chickpea-fallow-chickpea. 

Rainfall in the district is scanty. But, winter 2004-5 has been unique 

when continual rains were received during the growing season of winter 

crops. For the chickpea crop it has been a bad year because the excessive 

rains promoted vegetative growth and partitioning towards the seed yield 

had been lower. Moreover, water stayed unabsorbed in the fields of 

heavy soils, it severely affected the crop growth. The altered pattern of 

rain also affected the weed composition in the crop as well. 

Chickpea is heat tolerant and thrives under good moisture 

conditions with daytime temperatures between 21ºC and 29ºC and night 

temperatures near 20ºC. Chickpea is relatively drought tolerant due to its 

long taproot, which allows it to use water from greater depths than other 

pulse crops (MINFAL, 2004). 

In addition to rice-based, irrigated by the streams from mountains 

and rain-fed chickpea is also grown in the District, but the major bulk 

comes from the rice-based cropping system. Wild edible pea (L. sativus 

L.) and meadow peavine (L. aphaca L) are the worst weeds competitive 

with the chickpea crop in Dera Ismail Khan. The former weed infests the 

crop to an extent that crop is harvested as forage to feed the cattle and no 

longer goes to maturity. Hence, a proper assessment of the problem and 

find solutions is the need of the hour, so to save the growers from such a 

colossal loss. 

Materials and methods 

Five villages were randomly selected from the chickpea growing 

area of the district during winter season 2005-06. All the selected 

locations were either irrigated by streams from mountains, irrigated or of 

residual moisture from the preceding rice crop (rice-based). No 

herbicides were used at these sites throughout the growing season of 

crop. Seven to eight weeks after sowing of chickpea, in Dera Ismail Khan 

district of Pakistan, species-wise weed density m -2 was taken in the 

selected villages and from the same data relative density (%), frequency 

(%), relative frequency (%) and importance value of weed species were 

computed as adopted from Hussain (1989) and Hussain et al. (2004). At 

each of the selected villages, three fields of different chickpea were 

selected randomly and were surveyed following the methodology of 

Thomas (1985) and McCully et al. (1991). Five 1x1 m 2 quadrates were 

randomly placed along an inverted horizontal pattern in each field. The 

distance between each quadrate depended upon the size and shape of the 

field and any obstructions that may have been present in the fields. The 

22

Distribution of weed flora in chickpea crop in district Ismail Khan, Pakistan 

larger was the field, the greater was the distance between the quadrates. 

The collected weed samples were identified from the Department of 

Weed Science, NWFP Agricultural University, Peshawar and the 

Department of Botany, University of Peshawar. The samples were 

deposited into the herbarium of the Department of Weed Science, NWFP 

Agricultural University, Peshawar. 


Density of weed m -2 

Enormous variability in weed dynamics was observed across the 

5 locations studied (Table-I). Almost 9 times higher infestation was 

recorded at Darban road location as compared to the lowest infested site 

which is Kech area. At the most infested site of Daraban road 66.6 plants 

m -2 of Melilotus indica were recorded which is an enormous infestation. 

Numerically the same density (33.3 m -2 ) was recorded for Lathyrus 

aphaca L, Lathyrus sativus L. and Medicago denticulata (Table-I). M. 

denticulata emerged as the dominant species at Ghaebbi-2, Ghaebbi-1 

and Kech locations by counting 76.6, 45.3 and 5.8 plants m -2 , 

respectively (Table-I). Computing the means for each species across all 

locations, M. denticulata (34.26 m -2 ) was deciphered to be predominant 

species followed by M. indica (19.68 m -2 ) and L. aphaca (10.34 m -2 ). 

Convolvulus arvensis (3.32 m -2 ) and Rumex crispus (5.64 m -2 ) were the 

least abundant species in the studies (Table-I). 

Relative density (%) of weeds 

Analysis of the data revealed that the highest percentage (75.2%, 

67.5%, 28.4%) of flora comprised of M. denticulata at Ghaebbi-1, 

Ghaebbi-2, and Kech, respectively (Table-II). Whereas, in Daraban road 

site and Thatta area were predominated with M. indica (43.6%) and 

Lathyrus aphaca L (43.4%). The data exhibit that C. arvensis was 

endemic to Daraban road and did not exist at any other location (Table- 

2). Lathyrus sativus L., the worst weed of chickpea in the rice based 

cropping system was present in 4 out of 5 sites. Its share among the total 

flora ranges between 5.8% at Ghebbi-2 to 15.9% in the Thatta site. The 

relative density of this weed is low moderate, but the damage caused by 

it to the chickpea crop is maximum. L. sativus L. is a kind of vine having 

an enormous spread. One or two plants surround the chickpea plant and 

deprive it of solar radiation by overshadowing the crop. As compared to 

that L. aphaca has erect growth with a maximum height upto 15 cm does 

not have the same competitive ability. Thus, point of caution is hereby 

23


made that merely the number of weeds is not the index of harm it is 

rendering to the crop. The canopy structure (spread), height, leaf size, 

duration of competition are important to be kept into mind for assessing 

the harming value of weeds. 

Frequency (%) 

The data in Table-III evidence the strange composition of the 

studied sites. Both at Ghaebbi-1 or Ghaebbi-2 a weed was either absent 

or had 100% frequency, thus clearly depicting the even distribution of all 

present species in the chickpea fields. At Thatta the similar situation is 

witnessed except for Medicago had a frequency of 66.6%, while all the 

remaining present species were observed with a frequency of 100% 

(Table-III). At Daraban road and Kech preponderance Melilotus (66.6%) 

and Melilotus and Medicago both leguminous weeds with an equal 

frequency of 83.3%, were recorded respectively. The frequency analysis 

also shows Convolvulus as localized species occurring with a frequency 

of 16.6% at Daraban road. 

Relative frequency (%) 

A reference to data in Table-IV exhibits the supremacy of M. 

indica at all 5 locations. However, highest relative frequency of Melilotus 

was comparable with L. aphaca (27.2%) and Lathyrus sativus L. (27.2%) 

at Thatta. At Ghaebbi-1 and Ghaebbi-2, the highest frequency of 

Melilotus was at par with Medicago and Rumex. In addition at Ghaebbi- 

2, the relative frequency of Melilotus was also comparable with Lathyrus 

aphaca L (20%) and Lathyrus sativus L. (20%). At Kech, the relative 

frequency of Melilotus was comparable with Medicago (Table-III). Very 

little (9%) relative frequency was availed by Convolvulus arvensis 

indicating it as unimportant among the weed communities in chickpea 

crop of the studied area. 

Importance value of weed 

The computation of importance value is a good judgment for 

deciding the status of a given weed in community. Medicago denticulata 

was the predominant species at Ghebbi-1 (54.4), Ghaebbi-2 (43.7) and 

Kech (26.7). At the other two locations viz. Daraban road and Thatta. 

Melilotus indica and Lathyrus aphaca L with an Importance value of 

39.9 and 35.3, respectively, (Table-V). The lowest Importance value of 

5.2 was attained by the Convolvulus arvensis. Our findings are in great 

analogy with the work of Sultan and Nasir (2003) who observed different 

communities of weeds in gram fields of Chakwal at 8 different locations. 

24


The phytosociology in the gram fields they reported partially agrees with 

our findings. 

The appraisal on Average Importance value and ranking exhibits 

the Medicago denticulata, Melilotus indica, Lathyrus aphaca L and 

Lathyrus sativus L. as the important weeds of Dera Ismail khan, in the 

descending order. It is astonishing to note that all these are the broadleaf 

annual weeds belonging to the Leguminosae. Thus, all the species are the 

close relatives of chickpea (C. arietinum L.). Thus, their competition in 

chickpea is comprehended with the logic that due to their genetic 

relationship they required similar habitat for their growth. Hence, the 

planting and the crop management techniques which favored chickpea to 

become a dominant species also encouraged the growth of the referred 

leguminous weeds. 

As far as the management implications of these weeds are 

concerned their manual as well as chemical management tactics are 

threatened by their morphological and physiological resemblance with 

the chickpea. Our group has been fortunate enough to identify selectivity 

in chickpea to Stomp 330 E pre-em and isproturon which are effective on 

controlling some of the referred species (data not reported). 

Table 1. Density of weeds m -2 of various weed species across 5 locations 

in district Dera Ismail Khan, Pakistan 

Weed species 

Lathyrus aphaca L. 

Lathyrus sativus L. 

Family 

Leguminosae 

Leguminosae 

Daraban 

road 

Thatt 

a 

Area 

Ghaebbi 

-1 

Ghaebb 

i 

-2 

33.3 25.3 0.0 6.6 

33.3 9.3 0.0 6.6 

Kech 

area 

Mean 

s 

3.9 13.82 

2.5 10.34 

Melilotus indica L. All. Leguminosae 66.6 13.3 9.3 5.6 3.6 19.68 

Convolvulus arvensis L. Convolvulaca 

0.0 3.32 

16.6 0.0 0.0 0.0 

e 

Medicago denticulate L. Leguminosae 33.3 10.3 45.3 76.6 5.8 34.26 

Rumex crispus L. Polygonaceae 0.0 0.0 5.6 18.0 4.6 5.64 

Total 183.1 58.2 60.2 113.4 20.4 

25


Table 2. Relative Density (%) of various weed species across 5 locations in 

district Dera Ismail Khan, Pakistan. 

Weed species Family Daraban Thatta Area Ghaebbi- Ghaebbi-2 Kech Means 

road 

1 

area 

Lathyrus aphaca L. Leguminosae 29.9 43.4 0.0 5.8 19.1 19.64 

Lathyrus sativus L. Leguminosae 7.3 15.9 0.0 5.8 12.2 8.24 


Convolvulus arvensis L. Convolvulacae 1.6 0.0 0.0 0.0 0.0 0.32 

Medicago denticulate L Leguminosae 17.6 17.6 75.2 67.5 28.4 41.26 


Table 3. Frequency (%) of various weed species across 5 locations in 


Weed species Family Daraban Thatta Ghaebbi Ghaebbi Ketch Means 

road area 1 2 

area 

Leguminosae 100 100 0.0 100 66.6 59.98 



Leguminosae 100 100 0.0 100 50.0 56.66 

Melilotus indica L. All. Leguminosae 100 100 100 100 83.3 89.98 

Convolvulus arvensis L. Convolvulacae 100 0.0 0.0 0.0 0.0 3.32 

Medicago denticulate L. Leguminosae 100 66.6 100 100 83.3 76.64 

Rumex crispus L. Polygonaceae 0.0 0.0 100 100 50.0 50.0 

Table 4. Relative frequency (%) of various weed species across 5 locations 

in district Dera Ismail Khan, Pakistan 

Weed species Family Daraban Thatta Ghaebbi Ghaebbi Kech Means 

road area 1 2 area 

Leguminosae 18.0 27.2 0.0 20.0 19.9 17.02 



Leguminosae 18.0 27.2 0.0 20.0 15.0 16.04 


Convolvulus arvensis L. Convolvulacae 9.0 0.0 0.0 0.0 0.0 1.8 

Medicago denticulate L. Leguminosae 18.0 18.1 33.3 20.0 25.0 22.88 


26


Table 5. Importance value of various weed species across 5 locations in 


Weed species 

Lathyrus aphaca LL. 


Melilotus indica L. 

All. 

Convolvulus arvensis 

L. 

Medicago denticulate 

L. 

Rumex crispus L. 

Family 

Leguminosae 

Leguminosae 

Leguminosae 

Convolvulacae 

Leguminosae 

Polygonaceae 

Daraban 

road 

23.9 

12.6 

39.9 

5.2 

17.8 

0.0 

Thatta 

Area 

35.3 

21.5 

25.0 

0.0 

17.8 

0.0 

Gha 

ebbi 

-1 

0.0 

0.0 

24.2 

0.0 

54.4 

21.3 

Ghaeb 

bi-2 

Kech 

area 

12.9 19.5 

12.9 13.6 

12.4 21.3 

0.0 0.0 

43.7 26.7 

17.9 18.7 

Mea 

n 

Imp. 

valu 

e 

Spp 

rankin 

g 

18. 

3 3 

12. 

1 4 

24. 

6 

1.0 

31. 

1 

11. 

6 

2 

6 

1 

5 

Conclusions and recommendations 

L. sativus L. and L. aphaca L (even if they are not dominant) are 

the worst weeds competitive with the chickpea crop in Dera Ismail Khan, 

Pakistan. The former weed species infests the crop to an extent that 

chickpea is harvested as a forage to feed the cattle and no longer goes to 

maturity. Hence, a proper assessment of the problem and finding 

solutions is the need of the hour, so to save the growers from such a 

colossal loss. In order to achieve economic yield, judicious management 

of weed is recommended in chickpea. 

References 

MINFAL. 2004: Agricultural Statistics of Pakistan. Ministry of Food, Agriculture and 

Livestock, Government of Pakistan, Islamabad. 

HUSSAIN, F. 1989: Field and Laboratory Manual of Plant Ecology. University Grants 

Commission, Islamabad, pp. 155-156. 

HUSSAIN, F., A. MURAD AND M.J.DURRANI. 2004: Weed communities in wheat 

fields of Mastuj, District Chitral, Pakistan. Pak. J. Weed Sci. Res. 10(3-4): 10(3- 

4):101-108.. 

27


HASSAN, G. AND I. KHAN. 2007: Post emergence herbicidal control of Asphodelus 

tenuifolius in desi chickpea, Cicer arietinum L. at Lakki Marwat, Pakistan. 

Pak. J. Weed Sci. Res. 13 (1-2):33-38. 

KHAN, I., G. HASSAN, M. IDRESS AND M.I.KHAN.2005: Survey of some weeds 

from District Karak, Pakistan. Pak. J. Pl. Sci. 11 (1): 29-31. 

McCULLY, K.M., G. SIMPSON, AND A.K.WATSON. 1991: Weed survey of Nova 

Scotia Lowbush (Vaccinilum angustifolium) fields. Weed Sci. 39 (2):180-185. 

SULTAN, S. AND Z.A. NASIR. 2003: Dynamics of weed communities in gram fields 

of Chakwal, Pakistan. First Int’l. Weed Sci. Conf. NWFP Agric. Univ., 

Peshawar Oct. 23-26. 

THOMAS, A.G. 1985: Weed Survey system used in Saskatchewan for cereal and 

oilseed crops. Weed Sci. 33 (1):34-43. 

28


ECOLOGICAL AND PLANT-GEOGRAPHIC ANALYSIS OF THE 

WEED FLORA IN ORGANIC PRODUCTION OF BRASSICAS 

Aleksa Knežević, Slobodanka Stojanović, Ljiljana Nikolić, 

Branka Ljevnaić, Dejana Džigurski, Dragiša Milošev 

Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovića 8, Novi Sad, 

Serbia 

e-mail: kneza@polj.ns.ac.yu stojs@polj.ns.ac.yu ljnik@polj.ns.ac.yu 

brana@polj.ns.ac.yu dejana@polj.ns.ac.yu mildr@polj.ns.ac.yu 

Abstract 

In a study conducted at Vozars farm near the village of Kisač (the 

Vojvodina Province, Serbia) in the course of the 2008 growing season, 

35 plant species were found to comprise the weed flora present in the 

organic production of brassicas. Out of the total number of taxons found, 

29 were weed-ruderal, 4 were ruderal (of which one taxon is also treated 

as a forest-meadow weed and another as a weed-ruderal plant) and 2 

were segetal (cropland) weeds. Most of the detected weeds had the 

flowering time from April till September. Therophytes predominated in 

the studied agroecosystem. The detected weed flora indicated that the 

studied site had non-saline, moderately moist and neutral soil, rich in 

biogenous mineral substances, with a medium humus content, well 

aerated, with favorable light and thermal regimes which were in 

agreement with the conditions of the moderately continental climate. The 

weeds were adapted to these conditions and they tended to mechanically 

smother the cultivated plants. They also decreased the amounts of 

nutrients and water in the soil. Their permanent control is necessary for 

these reasons. If weeds are removed before they reach the stage of full 

flowering or seed maturity, we can control their occurrence in the 

subsequent growing season. 

Keywords: ecological and plant-geographic analysis, weed flora, brassicas, organic 

production. 

Introduction 

Organic agriculture is a system of ecologically balanced 

agricultural production aimed at intensifying the biodiversity of 

agrobioecosystems, matter cycling and biological soil activity. Its basic 

objective is the production of safe food, free of pesticides, growth 

regulators and mineral fertilizers. On the other hand, it favors the use of

A. Knežević et al. 

organic and biofertilizers while taking in account mutual interactions 

between soil, plants, animals and humans (Kovačević, 2008). 

An especially interesting segment of organic agriculture is the 

production of vegetables which diversify the human diet. An obvious 

shortcoming of organic vegetable production, in both field and 

greenhouse, is decreased productivity due to reduced yields. Because 

chemical control measures are almost fully excluded, dependence on 

climatic conditions tends to increase. The amount of manual labor is also 

increased but it does not reduce proportionally the rate of weed 

infestation. Instead, plant diseases and pests are encountered more 

frequently. Due attention should be paid to weed control in organic 

vegetable production because numerous problems arise if it is not 

adequate. 

Most effective measures to control excessive weed infestation, 

plant diseases and pests in organic vegetable production are proper soil 

tillage, correct crop rotation, use of certified planting material, protection 

of beneficial plants and animals and creation of favorable conditions for 

their development, and mechanical pest control (Knežević et al., 2008). 

The objective of this study was to assess the ecological and plantgeographic 

characteristics of the weed flora occurring in the course of 

organic production of brassicas because, in order to control weeds 

correctly and effectively, it is necessary to know their biology and 

ecology. 


A study of weed flora occurring in the course of organic 

production of brassicas in the field was conducted at the Vozars farm 

located near the village of Kisač (the Vojvodina Province, Serbia) in the 

course of the 2008 growing season. 

The soil type at the studied site was the calcareous black meadow 

soil on the loess terrace (Živković et al., 1972). 

The previous crops to the brassicas had been the table beet (Beta 

vulgaris L. subsp. esculenta Salisb.) in 2006 and the lettuce (Lactuca 

sativa L. subsp. capitata L.) in 2007. 

The following brassicas were grown in the course of the 2008 

growing season: the heading cabbage (Brassica oleracea L. var. capitata) 

including cultivars with white, red and cone-shaped heads, the kale 

(Brassica oleracea L. var. sabauda L.), the Chinese cabbage (Brassica 

oleracea L. v broccoli ar. chinensis), the cauliflower (Brassica oleracea 

L. var. botrytis L.), the romanesco broccoli (Brassica oleracea L. var. 

30

Ecological and plant-geographic analysis of the weed flora in organic production ... 

botrytis L. type romanesco), the broccoli (Brassica oleracea L. var. 

botrytis subvar. cymosa /var. italica) and the collard (Brassica oleracea 

L. var. acephala DC). 

The observed taxa were determined according to "The Flora of 

SR Serbia" (Josifović, 1970-1977), "Flora Europaea" (Tutin et al., 1960- 

1980) and "Iconography of the Flora from the South-Eastern Part of 

Central Europe" (Jávorka & Csapody, 1975). 

Table 1 provides the following data for each plant species listed: 

life form (Ujvárosi, 1973), date of flowering and category according to 

site (Čanak, Parabućski, S., Kojić, 1978); floristic element (Gajić 1980) 

and ecological indices according to Landolt (Landolt, 1977; Knežević, 

1994; Knežević et al., 2008). 


The weed flora observed during the organic production of 

brassicas at the Vozars farm (Kisač, the Vojvodina Province, Serbia) in 

the course of the 2008 growing season comprised of 35 taxa (Table 1). 

Of the total number of the detected taxa, 29 were weed-ruderal species, 4 

were ruderal species (among which one taxon is also categorized as a 

meadow and forest weed and another as a weed-ruderal species) and 2 

taxa were segetal weeds. 

Most of the detected taxa flowered in the period between April 

and September. Two taxa (Lamium aplexicaule and Senecio vulgaris) 

flowered already in March, three taxa (Chenopodium album, 

Chenopodium hybridum, Senecio vulgaris) still flowered in November, 

as many as nine taxa still flowered in October, and one taxon (Stellaria 

media) flowered all year round (Table 1). 

The analysis of the biological spectrum of the flora in the studied 

area indicated a predominance of therophytes whose abundance rate was 

80.00% (28 taxa). Among them, T 4 therophytes (62.85%, 22 taxa), which 

germinate in the spring and whose seeds mature in late summer, were 

most numerous. T 1 , T 2 and T 3 therophytes were present in lower 

percentages (11.43% or 4 taxa, 2.86% or 1 taxon and 2.86% or 1 taxon, 

respectively). The abundance rate for geophytes was 14.28% (5 taxa). 

The rates for G 1 and G 2 geophytes were 8.57% (3 taxa) and 5.71% (2 

taxa), respectively. Hemicryptophytes had the lowest abundance of 

5.72% (2 taxa) (Figure 1). 

31


Table 1. The weed flora of brassicas in organic production 

Time of Category 

Floral 

Ecological index 

flowering according to site element F R N H D S L T K 

Plant species 

Life 

form 

Abutilon theophrasti Meddik. T 4 VI-IX WR Adv. 2 3 4 3 4 - 4 5 3 

Agropyrum repens (L.) P.B. G 1 V-VI WR Evr. 3 3 4 2 3 + 4 3 3 

Amaranthus blitoides S. Watson T 4 VI-IX WR Adv. 2 4 4 4 4 - 5 4 4 

Amaranthus retroflexus L. T 4 VI-IX WR Adv. 2 3 4 3 3 - 4 4 3 

Ambrosia artemisiifolia L. T 4 VIII-IX R Adv. 2 3 4 2 2 + 4 5 3 

Anagallis arvensis L. T 4 V-X WR Cosm. 3 3 3 3 4 - 4 4 3 

Anagallis femina Mill. T 4 V-VI WR Cosm. 2 3 3 3 4 - 3 3 4 

Artemisia vulgaris L. H 5 VII-IX R, MW, FW Cirk. 3 3 4 3 4 - 4 4 3 

Bilderdykia convolvulus (L.) Dum. T 4 VI-IX S Subevr. 2 3 3 3 4 - 4 4 3 

Capsella bursa-pastoris (L.) Med. T 1 IV-XI WR Cosm. 2 3 4 3 4 - 4 4 3 

Chenopodium album L. T 4 VI-XI WR Cosm. 2 3 4 3 4 - 4 3 3 

Chenopodium hybridum L. T 4 V-VIII WR Subcirk. 3 4 4 3 3 - 4 4 4 

Cirsium arvense (L.) Scop. G 3 VI-VIII WR Subevr. 3 3 4 3 4 + 3 4 3 

Consolida regalis S. F. Gray T 2 V-IX WR Subse. 2 5 3 3 3 - 3 4 4 

Convolvulus arvensis L. G 3 VI-IX WR Cosm. 2 4 3 3 4 - 4 4 3 

Cynodon dactylon (L.) Pers. G 1 VI-VII WR Cosm. 2 3 3 3 3 - 4 5 2 

Datura stramonium L. T 4 VI-IX R Cosm. 3 3 4 4 4 + 4 5 2 

Heliotropium europaeum L. T 4 VII-IX WR Pont.-subm. 2 4 4 3 3 - 4 5 4 

Hibiscus trionum L. T 4 VI-VIII WR Pont.-is.- subm. 3 3 3 3 4 - 4 5 4 

Lamium amplexicaule L. T 1 III-VII WR Subevr. 2 3 4 4 4 - 4 3 3 

Matricaria inodora L. T 4 VI-X WR Evr. 3 3 4 4 4 + 4 3 3 

Panicum crus-galli L. T 4-T 4(h) VI-X S Cosm. 3 3 5 3 4 - 3 4 3 

Polygonum aviculare L. T 4 V-X R,WR Cosm. 3 3 4 3 5 - 4 3 3 

Polygonum lapathifolium L. T 4 VI-IX WR Subcirk. 3 3 4 3 3 - 5 3 3 

Portulaca oleracea L. T 4 VI-VIII WR Cosm. 3 3 4 3 4 - 4 4 3 

Rumex crispus L. H 3 VI-VIII WR Evr. 3 3 4 2 4 + 4 3 3 

Senecio vulgaris L. T 1 III-XI WR Evr. 3 3 4 3 4 - 4 4 3 

Setaria glauca ( L.) P.B. T 4 VI-X WR Cosm. 2 3 4 2 3 - 4 4 3 

Setaria viridis (L.) P.B. T 4 VI-X WR Subevr. 2 3 4 2 4 - 4 4 3 

Sinapis arvensis L. T 3 V-IX WR Subevr. 3 4 4 3 4 - 4 4 3 

Solanum nigrum L. T 4 VI-X WR Cosm. 3 4 4 3 4 - 4 4 3 

Sonchus oleraceus L. T 4 VI-X WR Subevr. 3 4 4 3 4 - 4 4 3 

Sorghum halepense (L.) Pers. G 1 VI-VII WR Cosm. 1 2 3 3 3 - 4 5 3 

Stachys annua L. T 4 VI-X WR Subpont-subm. 2 4 2 3 4 - 4 4 4 

Stellaria media ( L.) Vill. T 1 I-XII (III-V) WR Cosm. 3 3 4 3 4 - 3 3 3 

T- therophytes; G – geophytes, H – hemicryptophytes; W – weed species; WR weed-ruderal species; R – ruderal species; S – segetal weeds; MW – meadow weed; FW – forest weed; Adv. – Adventive; Evr.- 

Eurasian, Cosm. – Cosmopolitan; Cirk.- Circumpolar; Subevr. – Sub-Eurasian; Subcirk. – Sub-circumpolar; Subse. – Sub-Central European; Pont.-subm. – Pontic–dub-Mediterranean; Pont.-is. – subm. – 

Pontic–east sub-Mediterranean; Subpont-subm. – Sub-Pontic–sub-Mediterranean. 

32


% 

70 

60 

50 

40 

30 

20 

10 

0 

T1 T2 T3 T4 G1 G3 H3 H5 

Figure 1. Percentage values of life forms of the weed flora of 

brassicas 

The analysis of the ecological index for humidity indicated a 

predominance of mesophytes, labeled with the index F 3 (51.43%, 18 

taxa), and a significant percentage of sub-xerophytes, labeled with the 

index F 2 (45.71%, 16 taxa), which are adapted to relatively dry sites. 

Only one taxon (2.86%) was adapted to dry sites. The mean value of 

this index (2.5) was also an indication of a moderate humidity of the 

soil substrate at the studied site. 

The analysis of the ecological index for soil chemical reaction 

indicated a predominance of neutrophilic plants labeled with the 

index R 3 (71.42%, 25 taxa). Indicators of a neutral to a slightly 

aMWaline soil substrate labeled with the index R 4 were present at the 

rate of 22.86% (8 taxa), and only one taxon (2.86%) was adapted to 

each acid (R 2 ) and aMWaline (R 5 ) substrates. The mean value of this 

ecological index, amounting to 3.3, indicated the presence of a 

neutral to a slightly aMWaline soil substrate. 

The analysis of the ecological index for the content of 

nitrogen and nitrogen-containing compounds showed a predominance 

of indicators of eutrophic conditions of the site labeled with the index 

N 4 (71.42%, 25 taxa). Indicators of a moderate abundance of nitrogen 

(N 3 ) were also present in significant numbers (22.86%, 8 taxa). Only 

one taxon (2.86%) was adapted to each low (N 1 ) and very high (N 5 ) 

contents of biogenous mineral substances. The eutrophic conditions 

of the site were also confirmed by the mean value of this index (3.7). 

The analysis of the ecological index for the content of organomineral 

substances (humus) demonstrated a predominance of 

indicators of a medium humus content labeled with the index H 3 

(74.29%, 26 taxa). Indicators of a low humus content, labeled with 

the index H 2 , were present in a low percentage (14.29%, 5 taxa). 

33


Only 11.42% or 4 taxa showed the presence of a high humus level 

(H 4 ). The mean value of this indicator confirmed the prevalence of a 

medium humus content at the studied site (3.0). 

The analysis of the ecological index for soil dispersion 

(aeration) showed that the soil substrate was well aerated, with a 

predominance of indicators labeled with the index D 4 (68.57%, 24 

taxa). There was a significant proportion of indicators of very good 

aeration, labeled with the index D 3 (25.71%, 9 taxa). Only one taxon 

(2.86%) was adapted to each exceptionally good aeration (D 2 ) and 

exceptionally poor aeration (D 5 ). The good aeration of the soil 

substrate was also indicated by the mean value of this ecological 

index (3.7). 

The analysis of the ecological index for salinity indicated that 

the studied site was not saline, with a predominance of indicators 

labeled with the index S - (82.86%, 29 taxa). Presence of sporadic 

saline spots was indicated by a low percentage of taxa adapted to an 

increased content of Na + ions in the soil substrate (17.14%, 6 taxa). 

The analysis of the ecological index for light demonstrated a 

predominance of indicators labeled with the index L 4 (82.86%, 29 

taxa). Low percentages were registered for both, the indicators of 

semi-shade (L 3 – 11.42%, 4 taxa) and the indicators of very sunny 

sites (L 5 – 5.72%, 2 taxa). The high light intensity at the studied site 

was indicated by the mean value of this ecological index (3.9). 

The analysis of the ecological index for temperature showed a 

predominance of indicators of warm sites labeled with the index T 4 

(51.43%, 18 taxa). Lower percentages were registered for indicators 

of moderately warm sites, labeled with the index T 3 (28.57%, 10 

taxa) and indicators of very warm sites labeled with the index T 5 

(20.00%, 7 taxa). The favorable thermal regimen was confirmed by 

the site's mean value of this index (3.9). 

The analysis of the ecological index for continentality 

provided indication of moderately continental conditions of the 

studied site. The predominant plant indicator species were labeled 

with the index K 3 (74.28%, 26 taxa). A lower percentage was 

registered for the indicators of true continental conditions, labeled 

with the index K 4 (20.00%, 7 taxa). Only two taxa (5.72%) were 

indicators of sub-oceanic climate, those labeled with the index K 2 . 

The mean value of this index (3.1) confirmed the moderately 

continental climatic conditions of the studied area (Figure 2). 

34


100 

90 

80 

70 

60 

% 

50 

40 

30 

20 

10 

0 

F1 F2 F3 R2 R3 R4 R5 N2 N3 N4 N5 H2 H3 H4 D2 D3 D4 D5 S- S+ L3 L4 L5 T3 T4 T5 K2 K3 K4 

Figure 2. Percentage values of ecological indices of the weed flora of 

brassicas 

The plant-geographic analysis showed that 88.56% or 31 of 

the analyzed taxa belonged to plant species of wide distribution 

(40.00% or 14 cosmopolitan taxa, 5.72% or 2 sub-circumpolar taxa, 

2.86% or 1 circumpolar taxon, 17.14% or 6 sub-Eurasian taxa, 

11.42% or 4 Eurasian taxa, 11,42% or 4 adventive taxa). This was 

quite expected, since this analysis dealt with a weed sinusia. 

Four of the analyzed taxa 4 or 11.44% belonged to plant 

species of narrow distribution (2.86% or one Central European taxon, 

2.86% or one sub-Pontic–sub-Mediterranean taxon, 2.86% or one 

Pontic–sub-Mediterranean taxon, 2.86% or one Pontic–east sub- 

Mediterranean taxon). Since Consolida regalis is classified as a 

Central European plant according to Gajić (Gajić, 1980) and an 

Eurasian plant of Mediterranean origin according to Soό (Soό, 1966), 

we concluded that all of the analyzed species of narrow distribution 

were of Mediterranean provenience. The presence of plants of 

Mediterranean origin is due to the anthropogenic influence because 

the hoeing practice tends to increase the thermophilicity of the site 

(Figure 3). 

35


% 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

Cosm. 

Subcirk. 

Cirk. 

Subevr. 

Evr. 

Adv. 

Subse. 

Subpont.-subm. 

Pont.-subm. 

Pont.-is.-subm. 

Figure 3. Percentage values of floristic elements of the weed flora of 

brassicas 

The weed flora present in the organic production of brassicas 

was well adapted to the ambient conditions and it was found to have a 

long flowering period. Life form is a reflection of plant adaptation to 

the conditions prevailing in a given site. The predominant taxa in the 

studied agroecosystem were therophytes, which is characteristic for 

weed flora in general (Kojić et al., 1972). 

The observed weed flora was indicative of a moderately 

moist, neutral soil substrate rich in biogenous mineral substances and 

with a medium humus content, well-aerated, non-saline, with 

favorable light and thermal regimes, all of these features fitting the 

conditions of the moderately continental climate. The ecological 

conditions prevailing at the studied site were mostly in agreement 

with the ecological requirements of the dominant species – Brassica 

oleracea (F 3 R 3 N 5 H 3 D 4 S – L 4 T 4 K 2 ), which also confirmed that the 

weed sinusia was adapted to the conditions created by the cultivated 

crop. 

In light of the aforesaid, the resident weeds obviously tended 

to mechanically suppress the cultivated plants and reduce the 

amounts of available nutrients and water in the soil. Their permanent 

control is therefore necessary, which in this particular case was 

actually done by hoeing. 

However, beneficial action of weeds has also been noted. In 

periods of extreme drought, weeds prevented excessive soil drying 

36


and thus contributed to higher yields of the cultivated brassica crops 

(Knežević et al., 2008). 

In the course of brassica production, there is a period when 

weeds are permitted to grow. This period lasts from weed occurrence 

until the beginning of their large-scale flowering and seed maturation. 

If weeds are removed before they reach the stages of full flower or 

seed maturity, because they are mostly therophytes (in our case, 28 

out of the 35 weed species registered were therophytic), their 

numbers will be brought down to a tolerable level in the subsequent 

growing season. 

References 

ČANAK, M., PARABUĆSKI, S., KOJIĆ, M., 1978: Ilustrovana korovska flora 

Jugoslavije. Matica srpska. Novi Sad. 

GAJIĆ, M., 1980: Pregled vrsta flore SR Srbije sa biljnogeografskim oznakama. 

Glasnik Šumarskog fakulteta, serija A “Šumarstvo” 54, 111 -141 . 

Beograd. 

JOSIFOVIĆ, M. (ed.),1970-1980: Flora SR Srbije, 1-10, SANU, Beograd. 

JÁVORKA, S., CSAPODY, V., 1975: Iconographie der Flora des Südostlichen 

Mitteleuropa. Akademiai Kiado, Budapest. 

KNEŽEVIĆ, A.,1994: Monografija flore vaskularnih biljaka na slatinama u 

regionu Banata (Jugoslavija). Matica srpska, Novi Sad. 

KNEŽEVIĆ, A., STOJANOVIĆ, S., MAŠIREVIĆ, S., NIKOLIĆ, LJ., 

LJEVNAIĆ, B. 2008: Korovi kao vektori bolesti i štetočina u organskoj 

proizvodnji povrća. Zbornik radova sa naučno–stručnog skupa 

»Savremene tehnologije za održivi razvoj gradova, Banja Luka. 

KOJIĆ, M., STANKOVIĆ, A., ČANAK, M., 1972: Korovi – biologija i suzbijanje. 

Institut za zaštitu bilja, poljoprivredni fakultet u Novom Sadu. 

KOVAČEVIĆ, D., 2008: Njiski korovi - biologija i suzbijanje. Poljoprivredni 

fakultet Zemun, 1- 506. 

LANDOLT, E.,1977: Ökologische Zeigerwerte zur Schweizer Flora. 

Offentlichungen der Geobotanishen Institutes der ETH, Stiftung Rübel, 

Zürich, 64 Heft. 

ŽIVKOVIĆ, B., NEJGEBAUER, V., TANASIJEVIĆ, Đ., MILJKOVIĆ, N., 

STOJKOVIĆ, L., DREZGIĆ, P., 1972: Zemljišta Vojvodine. Institut za 

poljoprivredna istraživanja, Novi Sad, 1-685. 

SOÓ, R. 1966: A magyar flora es vegetacio rendszertani-novenyfoldrajzi 

kezikonyve, 1-7. Akademiai kiado, Budapest. 

TUTIN, G., HEYWOOD, V.H., BURGES, N.A., VALENTINE, D.H., WALTERS, 

S.M., WEBB, D.A. (ed.), 1964-1980: Flora Europea, 1-5, University 

press, Cambridge. 

UJVÁROSI, M.,1973: Gymnövények. Mezőgazdasági Kiado, Budapest, 1-833. 

37


DISTRIBUTION OF ASCLEPIAS SYRIACA L. ON THE 

TERRITORY OF VOJVODINA AND POSSIBILITIES OF ITS 

CONTROL 

Branko Konstantinović, Maja Meseldžija, Nataša Mandić 

Poljoprivredni fakultet Novi Sad, Departman za fitomedicinu i 

zaštitu životne sredine, 

Trg Dositeja Obradovića 8, 21 000 Novi Sad, E-mail: brankok@polj.ns.ac.yu 

Abstract 

Genus Asclepias comprises about 150 species, of which some 

are grown as horticultural plants, some as melliferous, and some as 

medical ones. In our country common milkweed or wild cotton 

(Asclepias syriaca L.) is one of invasive weed species that belongs to 

the family Asclepiadaceae. Common milkweed is heliophytic species 

distributed along roads, near forests, beside rivers on sandy and 

fertile solils. At Vojvodina territory it can be found near the Danube 

and Tisa rivers and near some smaller rivers in Vojvodina and Srem. 

The species propagates by seed or propagative roots that form 

adventitious buds that develop into new individuals. Common 

milkweed is used for obtaining of industrial fiber and as a mellifluent 

plant. In folk medicine, common milkweed leaves is used against 

cancer, tumor and skin warts. Plant parts of Asclepias syriaca L. are 

also known as folk medicine for asthma, bronchitis, cancer, cough, 

sneeze, dysentery, weak digestion, gewer, gonorrhea and rheumatism. 

This weed species invades fields with reduced tillage and insufficient 

use of herbicides, fertilizers and irrigation. It is easily adapted to 

fertile soil types. As weed species it occurs in maize crops. In our 

country Asclepias syriaca L. is a quarantine weed species from the 

list A2, list of harmful organisms that have been determined at the 

territory of the Republic of Serbia. 

Some herbicides are recommended for this weed’s control. 

Key words: common milkweed, distribution, control 

Introduction 

Common milkweed or wild cotton (Asclepias syriaca L.) is 

one of invasive weed species in our country, it belongs to the family 

Asclepiadaceae. Genus Asclepias comprises about 150 species of 

which some are grown as horticultural plants, some as melliferous, 

and some as medical ones (Konstantinovic et al., 2005). The most

B. Konstantinović et al. 

distributed species of the genus Asclepias are: A. asperula, A. 

incarnata, A. latifolia, A. linearis, A. obovata, A. oenotheroides, A. 

perennis, A. syriaca, A. texana, A. tuberose, A. verticillata, A. 

viridiflora, and A. viridis. Common milkweed (Asclepias syraca L.) 

originates from North America and at the beggining of the ninteenth 

century it was introduced into Europe. This species is found in many 

European countries such as Austria, Bulgaria, Czech Republic, 

Slovakia, France, Switzerland, Italy, Hungary, Poland, Romania, 

central part of Russia and countries of former Yugoslavia, especially 

in parts with mild winters (Tutin et al., 1972). 

Habitat 

Common milkweed is a heliophytic species distributed along 

roads, near forests, beside rivers on sandy and fertile solils. At 

Vojvodina territory it can be find near Danube and Tisa and near 

some smaller rivers in Vojvodina and Srem. On UTM map of 

Vojvodina, Igic et al., (2003) distribution of A. syriaca is represented 

based upon terrain studies and literature data (Konstantinovic et al., 

2003). Vrbnicanin et al. (2008) gave spatial distribution of this 

species at UTM network for the territory of whole Serbia. Woodson 

(1964) and Dyon (1958) both report that the habitual distribution of 

this plant is limited by 18 and 32 o C mean July temperatures in the 

north and south respectively and growth is dependant on adequate 

levels of rainfall in the three summer months. Excessive moisture 

may be inhibitory and best sites offer warm and dry soils that benefit 

from good exposure and drainage, the best growth rates achieved in 

30% of full sun (Berkman, 1949). 

Morphology 

Common milkweed is a perennial herbage weedy species with 

perpendicular stem that grows up to 150 cm in height (picture 1). 

Leaves are narrow elliptic, with light green down side, and dark green 

from the upper one. Flowers are coarse, pale pink to red in color. 

Fruits are elliptical, 6-10 cm in length, narrow from the both sides 

with thick hairs. Seed is oval, flat, brown with wide, ramply. Seed is 

egg like and oblate, with broad corrugated endings and foretop. All 

plant parts contain great quantity of milky juice that is poisonous due 

to glycoside contents harmful to hart. The sprouts contain 

asclepiadin, nicotine, β-sitosterol, α and β-amyrin and tannin (List 

and Horhammer, 1969-1979). 

40

Distribution of Asclepias syriaca L. On the territory of Vojvodina and ... 

Picture 1. Asclepias syriaca L. 

Biology and ecology of the species 

The species propagates by seeds and by underground 

rootstocks that develop adventitious buds which give rise to new 

individuals. Sprouting generally occurs during the first year of 

seedling growth but will take place anytime during the growing 

season if the plant or rootstock is disturbed. The parts of root can 

survive for two or more growing seasons. In northern half of its 

distribution aerial shoots emerge in April-May with active growth 

following the arrival of warmer waether and with increased foliage 

survace-root development commences (picture 3). The root begins 

its growth during spring and continues to develop durign sumer, 

while majority of shoots become senscent. Flowering occurs in late 

June-July and generally only on mature plants. Seedlings do not 

flower during their first year og growth (Bhowmik and Bandeen 

1970). 

41


Picture 2. Flowering of milkweed 

The species is described as being highly self-fertile (Moore, 

1947) and is generally pollinated by wasps and bees with only about 

2% of the flowers producing mature pods. Studies by Bhowmik and 

Bandeen (1976) show that an average plant produces 4–6 pods, each 

with 150-425 seeds. Seed pods split open early in the fall (September 

- October in northern regions), and the mature seeds are dispersed by 

the wind. Short to long distance dispersal is accomplished by seeds, 

but common milkweed also has the capability to multiply 

vegetatively. Within a period of 18-21 days after emergence, 

seedlings produce buds on the main root close to the ground surface 

(Bhowmik and Bandeen, 1970). Increase in number of new seedlings 

can be up to 21% when the top growth is removed (Evetts and 

Burnside, 1972). 

Common milkweed is used for obtaining of industrial fibre 

and as food-plant for bees. The seeds contain up to 20% of an edible, 

semi-drying oil (List and Horhammer, 1969-1979). 

According to Hager‘s Handbuch (List and Horhammer, 1969- 

1979), the latex contains 0.1-1,5% caoutchouc, 16-17% dry matter 

and 1.23% ash. It also contains α- and β- asclepiadin, the antitumor 

β-sitosterol and α- and β-amyrin and its acetate, dextrose and wax. 

Condurangin has also been reported from the seed, with at least 9 

active cardenolids, among them uzarigenin, desgiucouzarin, 

syriogenin, syriobioside, as well as xysmalogenin (List and 

Horhammer, 1969-1979). 

In folk medicine common milkweed leaves is used against 

cancer, tumor and skin warts (Hartwell, 1967-1971). Plat parts of A. 

42


syriaca are known as folk medicine for asthma, bronchitis, cancer, 

cough, sneeze, dysentery, weak digestion, gewer, gonorrhea and 

rheumatism (Duke and Wain, 1981; Kloss, 1939; Erichsen-Brown, 

1979). In India A. syriaca fibres are used for paper production 

(Spiridon, 2007). 

Distribution 

Originally from eastern North America, the plant is found in 

southern Manitoba and all the eastern provinces except 

Newfoundland (Frankton and Mulligan, 1987). The geographical 

distribution of this weed in North America is 35 o and 50 o nort 

latitude and 60 o and 103 o west longitude (Woodson, 1954; Doyon, 

1958). The greatest population were found in the southern parts of 

Canada, Ontario and Quebec (Bhowmik and Bandeen, 1976). 

According to literature data, A. syriaca was an early introduced 

species from North America to southern Europe (Bhowmik and 

Bandeen, 1976). By the end of 20 and at the beginning of 21 century 

in central and eastern Europe the invasion of exotic plants was 

significantly increased. Hungary belongs to transitional zone between 

deciduous forests and prairie in which this species also spreads 

(Kovacs-Lang et al. 2000). 

This weed species invades fields with reduced tillage and 

insufficient use of herbicides, fertilizers and irrigation (Cramer and 

Burnside 1981). It does not depend upon soil pH nor altitude and it is 

easily adapted to fertail soil types (Evetts 1977). As weed species it 

occurs in maize crops. In our country Asclepias syriaca L. is 

quarantine weed species from the list A2 (Anonymus, 2008). 

Possibilities of control 

Basic soil cultivation will result in removal of common 

milkweed seedlings in age of three weeks only. Mowing three times a 

year will eliminate and destroy common milkweed. A. syriaca will be 

eliminated also by sowing of winter cultures. As it is quarantine 

species, its introduction with the seed material is prevented . 

Various herbicides are used depending upon plant 

development phase and time of herbicide use (Cramer and Burnside, 

1981). Herbicide use includes seedlings treatment (Burnside, 1977). 

Herbicides for the control of this weed species in the world are: 

metribuzine, EPTC, atrazine, as well as their combination. Herbicide 

combination that proved to be highly efficient is amitrole and 

43


glyphosate. Herbicide combinations and formulations include also 

2,4-D, mecoprop, dicamba, and MCPA, that destroy parts of plants or 

the plant in whole (Bandeen, 1971, Evetts and Burnside, 1972). 

Results obtained by glyphosate use in rate of 2,2 kg ha -1 in early 

phase proved as good, as well as herbicide combination of glyphosate 

and amitrole in later phase (picture 3). Glyphosate showed good 

efficiency in many cases. However, if it is applied in full plant 

growth or in later develophment phases, i.e. after 4-6 developed 

leaves, rates of even 8 l ha -1 of glyphosat has no efficiency. 

Picture 3. Milkweed after treatment with 3,84 l ha -1 a.m. glyphosate 

in drainage canals 

References 

ANONYMUS, 2008. Laboratorija za invazivne korove. Available at 

http://polj.ns.ac.yu/~korovi/asclepias_syriaca.html 

BANDEEN, JD., 1971. Milkweed control. Res. Rep. Can. Weed Comm. East. Sect. 

234-234. 

BERKMAN, B., 1949. (In: Bhowmik, Bandeen. 1976) Milkweed-A war strategic 

material and a potential industrial crop for sub-marginal lands in the 

United States. Econ. Bot. 3:223-239. 

BHOWMIK, PC., BANDEEN, JD. 1970. Life history of common milkweed. Weed 

Sci. Soc. Amer. Abstr. No. 12. Asclepias syriaca L. Can. J. Plant Sci. 56: 

579-589. 

BHOWMIK, PC., BANDEEN, JD. 1976. The biology of Canadian weeds. 19. 

44


Burnside, O. 1977. Cultural, mechanical, and chemical control of common 

milkweed. Proc. Annu. Meet. North Cent. Weed. Control. Conf. 32:107- 

110. 

CRAMER, GL., BURNISIDE, O. C. 1981. Control of common milkweed 

(Asclepias syriaca) with postemergence herbicides. Weed. Sci. 29:636- 

640. 

ČANAK, M., PARABUĆSKI, S., KOJIĆ, M. 1978. Ilustrovana korovska flora 

Jugoslavije. Matica Srpska. Novi Sad. 

DOYONO, D. 1958 (In: Bhowmik,Bandeen. 1976): Etude de la distribution 

géographique de l´asclépiade commune (Asclepias syriaca L.) En 

Amérique du Nord. Rapp. Soc. Québec Protect. Plantes 40: 91-113. 

DUKE, J.A., WAIN, K.K. 1981. Medicinal plants of the world. Computer index 

with more than 85,000 entries. 3 vols. 

HARTWELL, J.L. 1967-1971. Plants used against cancer. A survey. Lloydia 30– 

34. 

ERICHSEN-BROWN, C. 1979. Use of plants for the past 500 years. Breezy Creeks 

Press. Aurora, Canada. 

EVETTS, L. 1977. Common milkweed-the problem. Proc. Annu. Meet. North. 

Cent. Weed Contr. Conf. 32:96-99. 

EVETTS, L., BURNISIDE,OC. (1972) (In: Bhowmik, Bandeen. 1976) 

Germination and seedlings development of common milkweed and other 

species. Weed Sci. 20:371-378. 

FRANKTON, C., MULLIGAN, GA. (1987): Weeds of Canada. Publication 948, 

NC Press, Agriculture Canada. 

IGIĆ, R., BOŽA, P., ANAČKOV, G., VUKOV, D., POLIĆ, D., BORIŠEV, M. 

2002-2003. Asclepias syriaca L. (cigansko perje) u flori Vojvodine. 

Zbornik radova Prirodno-matematičkog fakulteta, serija za biologiju, Novi 

Sad, 26-32. 

KLOSS, J. 1939. Back to Eden. Woodbridge Press Publishing Co., Santa Barbara, 

CA. 

KOVÁCS-LÁNG, E, KRÖEL-DULAY GY, KERTÉSZ M, FEKETE G, BARTHA 

S, MIKA J, DOBI-WANTOUCH I, RÉDEI T, RAJKAI K and HAHN I 

2000. Changes in the composition of sand grasslands along a climatic 

gradient in Hungary and implications for climate change. Phytocoenologia 

30: 385-407. 

LIST, P.H., HORHAMMER, L. 1969-1979. Hager’s Handbuch der 

pharmazeutischen Praxis. Vols. 2-6. Springer-Verlag, Berlin. 

MOORE, RJ. 1947. (In: Bhowmik, Bandeen.1976): Investigations on rubberbearing 

plants. V. Notes on the flower biology and pod yield of Asclepias 

syriaca L. Can. Field Natur. 61:40-66. 

SPIRIDON, I. 2007. Modifications of Asclepias syriaca fibers for paper 

production. Industrial Crops and Products, 26:265-269. 

TUTIN, T.G., HEYWOOD, V.H., BURGES, N.A., MOORE, D.M., VALENTINE, 

D.H., WALTERS, S.M., WEBB, D.A. 1972. Flora Europa III. Cambrige 

University Press, Cambrige. 

VRBNIČANIN, S., MALIDŽA, G., STEFANOVIĆ, S., ELEZOVIĆ, I., 

STANKOVIĆ-KALEZIĆ R., JOVANOVIĆ-RADOVANOV, K., 

MARISAVLJEVIĆ, D., PAVLOVIĆ, D., GAVRIĆ, M. (2008): Mapping 

of invasive non-native weed species in Serbia. Book of Abstracts Meeting 

Invasive Species, Osijek, Croatia, 23. 

45


WOODSON RE, Jr. 1954. (In: Bhowmik, Bandeen. 1976) The North American 

species of Asclepias L. Ann. Mo. Bot. Gard. 41. 

46


A STUDY OF ALLELOPATHIC EFFECT OF Amaranthus 

retroflexus (L.) AND Solanum nigrum (L.) IN DIFFERENT 

SOYBEAN GENOTYPES 

Aksenia Aleksieva, Plamen Marinov-Serafimov 

Institute of Forage Crops, Pleven, Pavlikeni Branch, Bulgaria 

aaleksieva@abv.bg; plserafimov@abv.bg 

Abstract 

Allelopathic effect of cold aqueous extracts from Solanum 

nigrum (L.) and Amaranthus retroflexus (L.) on seed germination and 

primary seedling growth and development was studied in different 

soybean genotypes with the purpose of finding accessions with an 

allelopathic potential and their inclusion as components in future 

breeding programmes. The aqueous extracts from S. nigrum and A. 

retroflexus suppressed the seed germination of the studied soybean 

genotypes by 41 to 78%, but this effect was statistically significant 

only in the variety Srebrina and line No. 5 a . The aqueous extract from 

A. retroflexus showed a more pronounced allelopathic effect on the 

studied soybean genotypes, as compared to those from S. nigrum. 

The studied varieties showed different susceptibility to the 

allelopathic effect of the S. nigrum and A. retroflexus extracts, which 

was due to their genetic differences. The varieties Mira and Divna 

possess allelopathic potential, because no significant allelopathic 

effect of the used extracts on them was found. These varieties can be 

used as components in future breeding programmes. 

Keywords: inhibition, weed extracts, allelopathic potential, soybean genotypes 

Introduction 

In the last decades the research work was focused on the study 

of allelopathic interrelations between cultivated plants and weed 

species with the purpose of finding varieties with high allelopathic 

potential (Rice, 1995). The discovery of varieties with high 

allelopathic potential provides a possibility for decrease of the inputs 

in agricultural crop growing and production of ecologically pure 

foods (Labrada, 2003). 

According to Ebana et al (2001), allelopathy can be 

considered as a means in the breeding programmes for biological 

control against weeds. Accessions with high allelopathic potential 

were discovered in many crops, such as: beet (Beta vulgaris L.), 

lupine (Lupinus lutens L.), maize (Zea mays L.), wheat (Triticum

A. Aleksieva and P. Marinov-Serafimov 

aestivum L.), oat (Avena sativa L.), pea (Pisum sativum L.), etc. 

(Rice, 1995). Fujii (1992) found that in rice there were also variety 

differences in allelopathic potential. 

Weed infestation of soybean stands in Bulgaria is of a mixed 

type with predominance of the annual late spring weeds (from 58 to 

92%) and they deteriorate the quality of the obtained produce and 

decrease the grain yield (Lyubenov, 1988). Prevailing weeds in the 

soybean stands for the conditions of Central North Bulgaria are 

Amaranthus retroflexus (L.) and Solanum nigrum (L.) (Marinov- 

Serafimov, Dimitrova, 2007). It was found that aqueous extracts from 

Amaranthus retroflexus (L.) and Solanum nigrum (L.) inhibited the 

germination and initial development of soybean seeds (Stoimenova, 

2002; Bensch et al., 2003), but there is no data on variety differences 

with regard to crop susceptibility. 

In the literature there is data on variety differences with regard 

to the allelopathic potential in different crops (Weston, 1996; 

Kostadinova et al., 2002; Labrada, 2003; Iman et al, 2006). In 

Bulgaria no results have been published till now concerning 

discovery of varieties with allelopathic potential. 

The objective of this study was to determine the allelopathic 

effect of cold aqueous exctracts from Solanum nigrum (L.) and 

Amaranthus retroflexus (L.) on seed germination and primary 

seedling growth and development in different soybean genotypes and 

discovery of accessions with allelopathic potential to be included as 

components in future breeding programmes. 


The study was conducted in 2007 in the laboratory of the 

Institute of Forage Crops in Pleven, Pavlikeni Branch, Bulgaria. 

Collection and Preparation of Plant Material 

Seeds of newly developed Bulgarian soybean lines, varieties 

and candidate varieties through different breeding methods were used 

(Table 1). 

Table 1. Soybean genotypes investigated 

№ Genotypes Mode of creation Maturity group 

1 Mira 96 – variety 

Experimental 

mutagenesis 

Middle early II 

2 Srebrina – variety Hybridization Middle early II 

3 Divna – candidate – Hybridization Ultra early 00 

48

A study of allelopathic effect of Amaranthus retroflexus (L) and Solanum ... 

variety 

4 

Karina - candidate – 

Middle early II 

Hybridization 

variety 

5 

Avigea – candidate – 

variety 

Hybridization Early I 

6 No. 5 а – Line Hybridization Early I 

7 М – 18/4 –Line 

Experimental 

mutagenesis 

Middle late III 

8 No. 21 – Line 

Interspecific 

hybridizatoin 

Ultra early- 00 

The seeds of the studied accessions were harvested in 2007. 

Above-ground biomass of Amaranthus retroflexus (L.) and Solanum 

nigrum (L.) was collected at the flowering stage of the weeds from 

experimental plots with a natural background of weed infestation. 

The plant material from the available weed species was dried to 

constant dry weight at 55 ± 3 0 С (Chon and Nelson, 2001). 

Preparation of Weed Extracts 

Eighty g of each weed species were cold extracted in 1 l 

distilled water at a temperature of 24 ± 2 0 С for 24 h in a shuttle 

apparatus at 240 rotations/minute. The obtained extracts were 

decanted, filtered with filter paper and centrifuged in „К24” 

centrifuge at 5000 rotations/minute. All available aqueous extracts 

were brought to final concentrations of 20, 40, 60 and 80 g dry 

biomass per liter distilled water (g/l), 2.0, 4.0, 6.0 and 8.0%, 

respectively. One g/l C 10 H 14 O was added to each extract as a 

preserving agent (Marinov–Serafimov et al., 2007). 

Bioassay Techniques 

In order to assess the effect of the tested cold aqueous extracts 

from A. retroflexus, and S. nigrum on the seed germination of test 

plants, 10 seeds of each genotypes were placed in Petri dishes, 90 

mm in diameter on filter paper. The extracts were pipetted in each 

Petri dishes in ratio 1:6 to seed weight (Serafimov et al., 2007). 

Distilled water was used as a control. Each variant had eight 

replications. 

The so prepared samples were placed in a thermostat at a 

temperature of 22 0 С ± 2 0 С (Moyer and Huang, 1997) for seven days 

(Adetayo et al., 2005, Liebman and David, 2006). The following 

parameters have been determined: initial seedling length (root + 

hypocotyl) (cm). Inhibition effect (in %) (IE) of the extracts on the 

germination and formation fresh biomass in g/germ was calculated 

49


following the formula forwarded by Ahn and Chung, 2000: IE = 

[(Control-Aqueous extracts)/Control)] x 100. 

Statistical analysis 

The percentage of seed germination was performed after 

preliminary transformation following the formula 

= arcsin x / 100 forwarded by (Hinkelmann and Kempthorne, 

Y 

% 

( ) 

1994) and have treated statistically by through the converted 

Fischer’s test by the „φ” method of Fischer (Plohinskii, 1967). The 

results obtained was calculated by programe product 

STATGRAPHICS Plus for Windows Version 2.1 at LSD 0.05%. 

Results and discussions 

The effect of aqueous extracts from A. retroflexus and S. 

nigrum on seed germination of the studied genotypes was in the 

following order: slight stimulatory effect – up to +4.2% → indifferent 

→ different degree of inhibition – from -5.5 tо -43.3%. According to 

the percentage of seed germination inhibition, the studied genotypes 

can be divided conventionally into three groups: I group ≤10% 

(Divna and line No. 21), II group - from 11 tо 20% (Мira, line М - 

18/4) and III group ≥21% (Кarina, Аvigea, line No. 5 а , Srebrina). In 

variety Mira the S. nigrum extract provoked a slight stimulatory 

effect of up to 4.19% (Fig. 1 and 2). The species and concentrations 

of the applied extracts had a substantial influence on laboratory seed 

germination of the studied soybean genotypes (Table 2). With 

increase of the concentrations there was a general tendency to its 

decrease in all genotypes by 41 tо 78%, as against the control variant, 

but statistical significance for the two extracts was found only in 

variety Srebrina and line No. 5 а t krit (P>0.05). Practically, the seed 

germination of variety Divna was not influenced by extract species 

and concentrations and are not significantly different at t krit 

(P


Inhibition effect (in %) (IE) 

Seed germination (in %) average for investigated concentrations by different 

soybean genotypes 

Control 

№21 

№18/4 

№ 5a 

Genotypes 

Avigea 

Karina 

Divna 

Srebrina 

Mira 

-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 

Germination, % 

Fig.1. Effect of aqueous extract from Solanum nigrum (L.) on the 

seed germination by different soybean genotypes (in %) and 

percentage of inhibition 

Inhibition effect (in %) (IE) 

Seed germination (in %) average for investigated concentrations by different 

soybean genotypes 

Control 

№21 

№18/4 

№ 5a 

Genotypes 

Avigea 

Karina 

Divna 

Srebrina 

Mira 

-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 

Germination, % 

Fig. 2. Effect of aqueous extracts from Amaranthus retroflexus (L.) on the seed 

germination by different soybean genotypes (in %) and percentage of inhibition 

51


Table 2. Effect of aqueous extracts from Amaranthus retroflexus (L.) 

and Solanum nigrum (L.) on seed germination of different soybean 

genotypes, % 

Concentrations of aqueous extract g/l 

Soybean genotypes Control 20 40 60 80 

Seed germination in % 

Mira 65 66 ns 69 ns 72 ns 69 ns 

Water extract of 

Solanum nigrum (L.) 

Water extract of 

Amaranthus 

retroflexus (L.) 

Srebrina 72 43* 49 ns 27*** 45* 

Divna 80 80 ns 80 ns 80 ns 72 ns 

Karina 77 65 ns 51* 51* 51* 

Avigea 70 59 ns 51 ns 47 ns 48 ns 

Line No. 5 а 82 53** 53** 59** 45*** 

М – 18/4 65 75 ns 49 ns 57 ns 53 ns 

Line No. 21 60 57 ns 53 ns 57 ns 57 ns 

Mira 65 72 ns 59 ns 43 ns 51 ns 

Srebrina 72 41** 51 ns 53 ns 35*** 

Divna 80 72 ns 80 ns 80 ns 59 ns 

Karina 77 59 ns 63 ns 63 ns 43*** 

Avigea 70 69 ns 55 ns 51 ns 25*** 

Line No. 5 а 82 55* 53** 39*** 57* 

М – 18/4 65 72 ns 57 ns 39 ns 47 ns 

Line No. 21 60 80 ns 49 ns 43 ns 48 ns 

Notice: The statistical processing to prove the differences in the seed germination 

was performed through the converted Fischer’s test „t φ ” by the „φ” method at 

t krit (P≥0.05)*; t krit (P≥0.01)**; t krit (P≥0.001)*** and ns – non significant. 

There was a specific variety reaction with regard to the 

inhibitory effect of the extracts on primary seedling growth in the 

studied genotypes. 

The studied concentrations of the S.nigrum extract in most 

genotypes did not exert a statistically significant inhibitory effect 

(Table 3). A significant inhibitory effect (from 25 to 53%) was 

observed only in varieties Srebrina, Karina and line No. 5 a . 

The concentrations of the aqueous extract from A. retroflexus 

showed a considerably stronger inhibitory effect on the studied 

genotypes, as compared to the concentrations of S. nigrum extract. 

The concentrations of 40 to 80 g/l provoked an inhibitory effect of 11 

to 55% on the primary seedling length of varieties Srebrina, Karina 

and lines М–18/4 and No. 21. Line No. 5 а was susceptible to all 

studied extract concentrations. A similar specific variety reaction in 

soybean and sweet maize was found by Iman et al., 2006. 

52


Data from biometric measurements of increase in primary 

seedling length allowed objective assessment of allelopathic potential 

at the initial stages of their development (Table 3). 

Table 3. Effect of aqueous extracts from Solanum nigrum (L.) and 

Amaranthus retroflexus (L.) on the growth of initial germ (root + 

hypocotyl) by different soybean genotypes, cm 

Soybean 

Solanum nigrum Amaranthus retroflexus 

g/l 

genotypes 

cm % cm % 

Mira 

0 3.30 ab (100) 3.30ab (100) 

20 4.90b (148) 4.36b (132) 

40 4.21ab (128) 3.53ab (107) 

60 3.85ab (117) 3.02ab (92) 

80 3.06a (93) 2.32a (70) 

Srebrina 0 4.71b (100) 4.71b (100) 

20 4.38b (129) 3.43ab (101) 

40 3.51ab (103) 2.88a (85) 

60 3.86ab (114) 3.05a (89) 

80 2.54a (75) 2.39a (70) 

Divna 

0 4.33a (100) 4.33a (100) 

20 3.85a (90) 3.72a (87) 

40 4.57a (106) 3.38a (79) 

60 4.10a (95) 3.64a (85) 

80 3.40a (79) 2.68a (62) 

Karina 

0 4.32b (100) 4.32c (100) 

20 4.09ab (95) 3.82bc (88) 

40 2.72ab (63) 3.39b (78) 

60 2.92ab (68) 2.49a (57) 

80 2.54a (59) 2.10a (49) 

Avigea 

0 4.00a (100) 4.00a (100) 

20 4.00a (100) 2.46a (62) 

40 3.84a (96) 3.08a (77) 

60 2.80a (70) 2.75a (69) 

80 2.20a (55) 2.40a (60) 

Line No. 5 a 0 5.90b (100) 5.90b (100) 

20 4.47ab (76) 3.42a (58) 

40 3.76ab (64) 3.16a (54) 

60 3.58a (61) 2.99a (51) 

80 2.79a (47) 2.71a (46) 

M-18/4 

Line No. 21 

0 4.90a (100) 4.90c (100) 

20 4.45a (91) 4.22bc (86) 

40 4.52a (92) 3.92abc (80) 

60 3.98a (81) 2.40ab (49) 

80 3.28a (67) 2.19a (45) 

0 3.60a (100) 3.60a (100) 

20 5.00a (139) 3.46a (96) 

53


40 5.24a (146) 3.13a (87) 

60 3.92a (101) 1.68a (47) 

80 3.41a (95) 2.40a (67) 

a, b, c LSD at 95% confidence interval 

That was probably due to considerably higher used 

concentrations of the extract, as compared to those found in the 

agrophytocenoses with falling off and decomposition of weed 

biomass in soil. 

The accumulation of fresh biomass in g per seedling also 

depended on extract species and concentrations (Table 4). 

Table 4. Effects of aqueous extracts from Solanum nigrum (L.) and 

Amaranthus retroflexus (L.) on the fresh biomass accumulation in g 

per initial germ (root + hypocotyl) by different soybean genotypes 

Soybean 

Solanum nigrum Amaranthus retroflexus 

g/l 

genotypes 

g % g % 

Mira 

0 0.10a (100) 0.10ab (100) 

20 0.15a (150) 0.13b (130) 

40 0.14a (140) 0.11ab (110) 

60 0.11a (110) 0.12ab (120) 

80 0.12a (120) 0.09a (90) 

Srebrina 0 0.12b (100) 0.12c (100) 

20 0.16c (133) 0.12c (100) 

40 0.17c (142) 0.09ab (75) 

60 0.13b (108) 0.08a (67) 

80 0.09a (75) 0.10b (83) 

Divna 

0 0.14a (100) 0.14a (100) 

20 0.16a (114) 0.12a (92) 

40 0.20a (125) 0.12a (92) 

60 0.20a (125) 0.13a (93) 

80 0.16a (114) 0.13a (93) 

Karina 

0 0.08a (100) 0.08a (100) 

20 0.13c (163) 0.10ab (125) 

40 0.10abc (125) 0.12b (150) 

60 0.12bc (150) 0.10ab (125) 

80 0.09ab (113) 0.10ab (125) 

Avigea 

0 0.15c (100) 0.15d (100) 

20 0.11b (73) 0.13cd (87) 

40 0.11b (73) 0.11bc (73) 

60 0.06a (40) 0.11bc (73) 

80 0.09b (60) 0.06a (40) 

Line No. 5 a 0 0.15ab (100) 0.15a (100) 

20 0.11ab (73) 0.12ab (80) 

40 0.09a (60) 0.12ab (80) 

54


M-18/4 

Line No. 21 

60 0.10a (91) 0.12ab (80) 

80 0.08a (53) 0.10a (67) 

0 0.19c (100) 0.19b (100) 

20 0.11a (58) 0.12ab (63) 

40 0.14b (74) 0.12ab (63) 

60 0.11a (58) 0.08a (42) 

80 0.11a (58) 0.10a (53) 

0 0.14b (100) 0.14c (100) 

20 0.13b (93) 0.12b (86) 

40 0.14b (100) 0.12b (86) 

60 0.10a (71) 0.08a (57) 

80 0.08a (57) 0.09a (64) 

a, b, c, d LSD at 95% confidence interval 

No statistically significant inhibitory effect of the studied 

concentrations of S. nigrum extract was found in varieties Mira, 

Divna and line No. 5 а . Variety Avigea and line M-18/4 can be 

determined as susceptible, because with increase of the extract 

concentration their inhibition degree increased by 13 to 60%, as 

against the control variant, the differences being statistically 

significant at Р=95%. 

The higher concentrations of 60 and 80 g/l had a statistically 

significant inhibitory effect on biomass accumulation in the primary 

seedling in line No. 21. In varieties Srebrina and Karina the 

concentrations of 20 and 60 g/l had a statistically significant 

stimulatory effect of up to 55%, as against the control variant with 

distilled water. 

The applied concentrations of the aqueous extract from A. 

retroflexus had no statistically significant inhibitory effect on fresh 

biomass accumulation in g per seedling in varieties Mira, Divna and 

line No. 5 а . A significant inhibitory effect of 14 to 43% of all applied 

concentrations (at P=95) was found only in line No. 21. In varieties 

Srebrina, Avigea and line M-18/4 the higher studied concentrations 

of 40 to 80 g/l showed also a significant inhibitory effect. The degree 

of inhibition of fresh biomass accumulation in g per seedling 

increased with increase of the extract concentrations, as follows: 

Srebrina – from 9 to 27%; Avigea – from 13 to 60%, line No. 5 а from 

20 to 33% and line M – 18/4 – from 37 to 58%. Therefore, the 

observed differences in soybean genotypes with regard to allelopathic 

effect of the extracts can be explained by genetic differences, because 

the comparisons between them were performed at equal 

concentrations of the applied extracts, which determined the presence 

of allelopathic potential in varieties Mira and Divna. Similar results 

in wheat were reported by Wu et al. (1998), according to whom the 

55


species of cultivated plants and varieties had different susceptibility 

to allelopathic effect of plant extracts and the allelopathic effect was 

species specific and depended on the concentrations (Einhelling, 

1996). 

There were also differences in allelopathic effect of the 

studied extracts on the tested genotypes depending on their maturity 

group, as well as within the maturity groups themselves. 

The aqueous extracts from the above-ground biomass of S. 

nigrum and A. retroflexus had no inhibitory effect on the primary 

seedling growth and fresh biomass accumulation in g per seedling in 

the ultra-early variety Divna, whereas line No. 21 from the same 

maturity group was highly susceptible with regard to fresh biomass 

accumulation in g per seedling at all concentrations and not 

susceptible with regard to primary seedling growth (Tables 3 and 4). 

The genotypes belonging to the early maturity group – Avigea and 

line No. 5 а also differed in their reaction to the applied extract species 

and concentrations. Significant suppression of primary seedling 

growth by the concentrations of the two extracts was not observed in 

variety Avigea , whereas line No. 5 а was susceptible at all A. 

retroflexus concentrations and at the higher S. nigrum concentrations. 

There was inverse relation with regard to fresh biomass accumulation 

in g per seedling. The concentrations of the S. nigrum and A. 

retroflexus extracts had a statistically significant inhibitory effect in 

variety Avigea, whereas line No. 5 а was not susceptible. 

Varieties Srebrina and Karina were susceptible to the higher 

concentration of A. retroflexus extract with regard to primary 

seedling growth, whereas variety Mira was not susceptible. The 

concentrations of the S. nigrum extract had no significant inhibitory 

effect on the primary seedling growth in varieties Mira, Srebrina and 

Karina, except for the 80 g/l concentration in varieties Srebrina and 

Karina. The extracts from S. nigrum and A. retroflexus did not show 

an inhibitory effect on the fresh biomass accumulation in g per 

seedling in varieties Mira and Karina, whereas Srebrina was 

susceptible to the allelopathic effect of the extracts. The middle late 

line M-18/4 showed susceptibility to the higher A. retroflexus 

concentrations and was not susceptible to the S. nigrum 

concentrations with regard to primary seedling growth. 

The extracts from S. nigrum and A. retroflexus had a strong 

allelopathic effect on the fresh biomass accumulation in g per 

seedling. Therefore among the studied genostypes allelopathic 

potential was present only in varieties Mira and Divna that can be 

56


used as components in development of varieties with improved 

allelopathic potential. 

Conclusions 

The aqueous extracts from S. nigrum and A. retroflexus 

suppressed the seed germination of the studied soybean genotypes by 

41 tо 78%, but this effect was statistically significant only in variety 

Srebrina and line No. 5 а . 

The aqueous extract from A. retroflexus showed a more 

pronounced allelopathic effect on the studied soybean genotypes, as 

compared to that from S. nigrum. 

The studied varieties showed different susceptibility to the 

allelopathic effect of the extracts from S. nigrum and A. retroflexus, 

which was due to their genetic differences. 

Varieties Mira and Divna possess allelopathic potential, 

because no statistically significant allelopathic effect of the used 

extracts was found in them. These varieties can be used as 

components in future breeding programmes. 

References 

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Germination and Seedling Performance of Selected Crop and Weed 

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common waterhemp (A. rudis) in soybean. Weed Science, 51(1):37 - 43. 

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Agronomy 5(1): 62-68. 

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allelopathic potential of Convolvulus arvensis leaves and roots. Journal of 

Environmental Protection and Ecology, 3:668-672. 

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Countries. Chapter 3, Management Options and Perspectives, Addenum 1, 

FOU Plant Production and Prrotection , Paper 120 Add, 1, Rome. 

LIEBMAN, M., N. DAVID, (2006): Seed mass affects the susceptibility of weed 

and crop species to phytotoxins extracted from red clover shoots, Weed 

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volume I, p. 186-195. 

MARINOV-SERAFIMOV, Pl., Ts. DIMITROVA, (2007): Dynamic and 

distribution of the main weeds in weed associations of some Grain- 

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MARINOV-SERAFIMOV, TS. DIMITROVA, I. GOLUBINOVA, A. ILIEVA, 

(2007): Study of suitability of some solutions in allelopathic researches. 

Herbologia, 8(1):1-10. 

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(2007): Study of water imbibing capacity of some legume crops under in 

vitro conditions in allelopathic researches. Herbologia, 8(2):29-40. 

MOYER, J., H. HUANG, (1997): Effect of aqueous extracts crop residues on seed 

germination and seedling growth of ten weed species, Bot. Bull. Acad. 

Sin., 38:131-139. 

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Moscow University, p. 74-78. 

RICE, E. L., (1995): Biological control of weeds and plant disease: Advances in 

applied Allelopathy. Norman, Oklahoma: University of Oklahoma Press. 

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Amaranthus retroflexus L. depending on some ecological conditions. 

Author’s dissertation abstract. 

WESTON, L., (1996): Utilization of allelopathy for weed management in 

agroecosystems. Agronomy Journal, 88:860–866. 

WU H., J. PRATLEY, D. LEMERLE, T. HAIG, B. VERBEEK, (1998): 

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Wagga . 

58


INVESTIGATION OF ALLELOPATHIC POTENTIAL OF 

BUCKWHEAT 

Mirha Đikić, Drena Gadžo, Taib Šarić, Teofil Gavrić, Ševal 

Muminović 

Faculty of Agriculture and Food Sciences, Sarajevo, 

Zmaja od Bosne 8, Sarajevo, Bosnia and Herzegovina 

m.djikic@ppf.unsa.ba 

Abstract 

Crop species with allelopathic potential have been given 

greater attention during the last two decades. Recently, utilization of 

the allelopathic potential of plants for weed control instead of 

herbicide application is given great emphasis, because it would 

reduce the risk of environmental toxicity. 

Buckwheat (Fagopyrum esculentum) is an economically 

important forage, grain and cover crop known for its allelopathic 

activity under field and greenhouse conditions due to its several 

allelochemicals. 

The main goal of our investigation was to explore allelopatic 

potential of buckwheat for weed control under field and laboratory 

conditions. 

Three cultivars of buckwheat were investigated in the field. 

Their potential of weed suppression was recorded. In the laboratory, 

we investigated the influence of the aqueous extract of above-ground 

parts of three cultivars on germination of Galium aparine, Rumex 

crispus, Galium molugo, and Abutilon theophrasti. Aqueous extract 

was prepared in the crop flowering and ripening stage. 

The field study showed that live buckwheat reduced total 

weed biomass compared with plots without any crop. But 

Amaranthus retroflexus and Hibiscus trionum (the most frequent 

weeds) were not suppressed by living buckwheat plants in high 

percent. 

Laboratory research showed that water extract of buckwheat 

cultivars in flowering stage suppressed root and shoot growth and 

germination of Rumex crispus, Galium molugo, and Abutilon 

theophrasti, while the influence on Galium aparine was reduced 

when we used 100% extract. 

These results suggest that buckwheat may have allelopathic 

potential and that, when used as a ground cover crop or green 

manure, may produce inhibitors, which could inhibit some weeds.

M. Đikić et al. 

Keywords: allelopathy, buckwheat, weeds 

Introduction 

In plant-plant interactions, allelopathy denotes the process by 

which plants release phytotoxic compounds (allelochemicals) in the 

soil environment, resulting in a harmful or beneficial effect on 

neighbouring plants. Both crops and weeds may contain compounds 

that can be considered allelopathic. Crop species with allelopathic 

potential have been given greater attention during the last two 

decades (Chou, 1999; Shilling et al., 1985; Weston 1996). However, 

only few crops have been studied thoroughly in terms of their weed 

suppressing activity (Einhellig, 1996; Rice, 1979). Crops with 

allelopathic properties may suppress subsequent crop growth. 

Recently, utilization of the allelopathic potential of plants for weed 

control instead of herbicide application is given great emphasis, 

because it could reduce the risk of environmental toxicity. 

Buckwheat is an agronomic species of the Polygonaceae 

family that belongs to the genus Fagopyrum. There are about 15 

species in the genus Fagopyrum, which occur in temperate areas of 

Euro-Asia. Plants in this family produce a wide array of biologically 

active constituents. As fast-growing cover crop, buckwheat is most 

useful for weed suppression. Fagopyrum esculentum Moench 

(common buckwheat) is known to Japanese farmers as cover crop 

since long for limiting soil erosion. There are some reports about its 

allelopathic activity in field and greenhouse. Experiments conducted 

under field conditions have shown that buckwheat shades and 

smothers weeds, or outcompetes them for soil moisture and nutrients 

(Tominaga and Uezu, 1995). 

Fagopyrum esculentum is an economically important forage, 

grain and cover crop and has shown allelopathic activity in field and 

greenhouse (Isojima et al., 2000). Some authors have reported several 

allelochemicals from F. esculentum (Iqbal et al., 2002, 2003). In 

continuation of their work another member of this genus F. tataricum 

Gaertner (tartary buckwheat) was investigated for its allelopathic 

potential. In this investigation, they isolated two flavonol glycosides 

and a flavonoid from the upper part of F. tataricum and determined 

their allelopathic effects on seed germination and seedling growth of 

lettuce (Lactuca sativa L.). 

60

Investigation of allelopathic potential of buckwheat 

Recently it has been reported that a compound with high total 

activity might act as communication device among organisms in the 

natural ecosystem (Hiradate et al., 2004). 

Among buckwheat species, F. tataricum is a species to note 

because it contains 50-130 times higher amount of rutin. All the 

flavonoids reported here, especially rutin, are known to have 

antibacterial, antiviral, antihypertensive, and antioxidant activities. 

These studies show that rutin is the potential allelochemical of F. 

tataricum, which along with other active constituents is responsible 

for the allelopathic activity of buckwheat. It is therefore possible that 

in future buckwheat could be used as ground cover crop. This will 

allow long-term weed suppression in agricultural systems through the 

release of allelochemicals. 

Buckwheat is known as good competitor. It competes well 

with weeds and suffers little from other pests. This may be because 

buckwheat contains allelopathic compounds and its cultivation was 

observed to reduce weed biomass (Iqbal et al., 2001). The phenolic 

compounds have wide biological activities and they are probably 

responsible for allelopathic potential of buckwheat. 

In practice, buckwheat is cultivated without pesticides. 

Furthermore, its soil nutritional requirements are low and therefore 

buckwheat was often the last crop in slash and burn farming systems 

of the past. 

The main goal of our investigation was to explore allelopatic 

activity of buckwheat for weed control under field and laboratory 

conditions. 


Two cultivars (from Slovenia) were investigated under field 

conditions. Their potential of weed suppression was recorded. The 

trial was set up in randomized block design with three replications for 

each cultivars. Basic plot area was 1 m 2 . The distance between 

replications was 1 meter. Check plots were set up too. During the 

buckwheat growing season we recorded the number and mass of 

weed species, the first time one months after sowing and the second 

time in July. 

61


Table 1. Main data on the experiment 

Trial location 

Butmir, central Bosnia 

Basic trial plot size 1 m 2 (1x1 m) 

Number of replications 3 

Cultivars 

Čebelica 

Darja 

Date of sowing April 14, 2007 

Seed rate per plots (1 m 2) 10 g 

First weed evaluation Juni 20, 2007 

Second weed evaluation July 31, 2007 

The aim of this experiment was to evaluate the influence of 

buckwheat stand on weeds in the field. 

The influence of the aqueous extract of above-ground portions 

of mentioned cultivars (and a domestic population) on the 

germination of Galium aparine, Galium molugo, Rumex crispus, and 

Abutilon theophrasti was investigated in the laboratory. Crop 

aqueous extract was prepared in the flowering and ripening stages. 

Above-ground biomass (stems and leaves) in the flowering stage 

(May 29 th ) and before harvest (July 31 st ) were sampled, than dried at 

40°C, cut and extracted with distilled water. 20 grams of buckwheat 

were chopped and soaked in distillated water for 24 hours. After that 

the soaked materials were filtered. The extract was diluted to a 50% 

concentration. 8 mililiters of extract were applied on a filter paper 

with 50 weed seeds in each Petri-dish, in four replications. 

The aim of the work was to evaluate the influence of water 

extracts, which were obtained from buckwheat plants, on the 

germination of tested weed seeds and so evaluate the allelopathic 

potential of buckwheat. We observed the number of germinated weed 

seeds and length of roots and sprouts. 

Field study 


Results of our investigation can be seen in the next table. 

Field study showed that living buckwheat reduced weed biomass 

compared with plots without buckwheat. 

62


Table 2. Number of weeds per m 2 

evaluation 

in buckwheat plots in first 

Weed species 

Čebelica 

Varieties 

Darja 

Check 

Amaranthus retroflexus 

80 73.2 

% of reduction 

25.7 32.0 

107.6 

Hibiscus trionum 

10.8 6.8 21.2 


49.1 67.9 

Capsella bursa-pastoris 

2.8 2.8 


79.4 79.4 

13.6 

Cirsium arvense 1.2 2.8 1.2 

Daucus carota 1.2 8 5.6 

Chenopodium album 9.2 9.2 5.6 

Trifolium repens 1.2 - 1.2 

Lamium purpureum 2.8 - 5.2 

Polygonum convolvulus 4 - 0.8 

Taraxacum officinale 5.2 - 3.6 

Veronica persica 2.8 4 5.2 

Plantago lanceolata 4 - 0.8 

Abutilon theophrasti - 1.2 - 

Sonchus arvensis - 2.8 - 

Convolvulus arvensis - 1.2 0.4 

Echinochloa crus-galli - - 5.2 

Solanum nigrum - - 0.4 

Agropyron repens - 6.8 0.8 

Polygonum lapathifolium - 1.2 0.4 

Geranium dissectum - 1.2 0.4 

Euphorbia helioscopia 1.2 - 1.2 

Total weed number 


126.4 

29.9 

121.2 

32.8 

180.4 

0 

Redroot pigweed (Amaranthus retroflexus), flower-of-an-hour 

(Hibiscus trionum), and shephard ' s purse (Capsella bursa-pastoris) 

belonged to most numerous weeds in the buckwheat stand in the first 

evaluation. 

63


Table 3. Number and mass of weeds per m 2 in buckwheat plots in 

second evaluation 

Weed species 

Varieties 

Check 

Čebelica Darja 

num- mass num-ber mass number 

mass 

ber g 

g 

g 

Amaranthus retroflexus 124 745 110 690 


40.7 31.8 47.4 37.5 

209 1104 

Hibiscus trionum 

25.2 36 6.8 12 21.2 67.8 


- 46.9 67.9 82.3 

Chenopodium album 9.2 22 8 23.6 


- 38.2 - 33.7 

8 35.6 

Chenopodium polyspermum 2.8 5.6 1.2 2 


48.2 72.3 77.8 90.1 

5.4 20.2 

Polygonum convolvulus 1.2 4.4 2.8 6.4 4 3.2 


70 - 30 - 

Cirsium arvense 1.2 15.2 4 203 1.2 7.2 

Taraxacum officinale 1.2 3.2 - - 8 67.6 

Veronica persica - - - - 2.8 1.6 

Capsella bursa-pastoris - - - - 6.8 2 

Plantago lanceolata 2.8 2 - - - - 

Daucus carota 2.8 2.8 

Abutilon theophrasti - - 1.3 3.6 

Sonchus arvensis - - 1.2 29.2 1.2 10.4 

Convolvulus arvensis 2.8 2 14.8 24.8 2 2.4 

Echinochloa crus-galli - - - - 4 54 

Solanum nigrum - - - - 2,8 6,4 

Polygonum lapathifolium 2.8 1.6 1.2 2.4 - - 

Geranium dissectum - - - - 2.8 6.8 

Mentha arvensis 8 23.2 - - - - 

Chenopodium polyspermum 2.8 5.6 1.2 2 


48.2 72.3 77.8 90.1 

5.4 20.2 

Setaria glauca - - 5.2 10.4 51.2 177.6 

Cycorium inthybus - - - - 1.2 8 

Linaria vulgaris - - - - 1.2 2 

Rorypa sylvestris - - - - 1.2 19.2 

Total weed number and 

mass 


181 

46.2 

860 

46.3 

157 

53.4 

1007 

37.1 

336.8 

100 

1599 

100 

Amaranthus retroflexus, Hibiscus trionum, Chenopodium 

album, and Chenopodium polyspermum belonged to the most 

numerous weeds in the buckwheat during the second evaluation. 

Total weeds number and mass were reduced for 46.2 and 53.4 by 

Čebelica, and for 46.3 and 37.1 by Darja, respectively. 

64


The number and mass of Amaranthus retroflexus was reduced 

by Čebelica and Darja (40.7, 47.4, 31.8, 37.5 respectively). 

Haramoto and Gallandt (2005) evaluated the effects of 

incorporated buckwheat residues on selected weeds and crop species. 

They demonstrated that fresh buckwheat residues delayed as well as 

suppressed the emergence of Amaranthus retroflexus and 

Chenopodium album. However, the effects on their subsequent 

growth were not measured. 

Laboratory study 

In the laboratory studies, aqueous extracts of the aerial parts 

of common buckwheat were investigated. In the next tables one can 

see the results of the investigation. 

Table 4. The influence of 100% buckwheat extract on Galium 

aparine seed germination 

Traits 

Sprout 

number 

Root 

lenght 

Sprout 

lenght 

Čebelica, 

flowe 

ring 

Darja, 

flowering 

V a r i a n t s 

Domes Čebelica, 

-tic, 

flowering 

ripening 

Darja, 

ripening 

Che 

ck 

LSD 

0.05 

LSD 

0.01 

13.5 - - 32.0 - 35.3 - 40.5 34.0 - - 45.5 8.23 10.04 

0.55 - - 0.63 - - 0.83 - - 1.50 - - 0.85 - - 6.38 0.44 0.54 

0.91 - - 0.93 - - 2.75 - - 2.88 - - 1.80 - - 4.38 0.93 1.14 

Buckwheat extracts highly reduced root and sprout lenght of 

G. aparine, but sprout number was not diminished by Čebelica in 

ripening stage. 

Table 5. The influence of 50% buckwheat extract on Galium aparine 

seed germination 

Traits 

Čebelica 

flowe 

ring 

Darja 

flowering 


Domes 

tic 

flowering 

Čebelica 

ripening 

Darja 

ripening 

Che 

ck 

LSD 

0.05 

LSD 

0.01 

Sprout 45.0 45.3 43.0 47.0 49.8 + 44.8 4.67 5.70 

number 

Root 4.38 - - 5.15 - - 5.83 - - 6.33 5.88 - - 7.43 1.19 1.45 

65


length 

As it can be seen, 50%-extract of investigated buckwheat 

cultivars reduced root length of G. aparine, except cv. Čebelica in 

ripening stage. 

Table 6. The influence of 100% buckwheat extract on Rumex crispus 


Traits 

Sprout 

number 

Root 

length 

Sprout 

length 

Čebelica 

flowering 

Darja 

flowering 


Domestic 

flowering 

Čebelica 

ripening 

Darja 

ripening 

Che 

ck 

LSD 

0.05 

LSD 

0.01 

46.5 39.3 - - 48.8 41.5 - 35.5 - - 51.0 9.25 11.62 

0.96 - - 0.51 - - 0.43 - - 0.76 - - 0.36 - - 2.65 0.41 0.50 

1.83 - - 2.48 1.50 - - 2.55 2.01 - - 2.53 0.39 0.48 

All cultivars reduced germination of R. crispus, expect by cv. 

Čebelica and Domestic cultivar in flowering stage. 

Table 7. The influence of 50% buckwheat extract on Rumex crispus 


Traits 

Sprout 

number 

Root 

lenght 

Sprout 

lenght 

Čebe 

lica 

flowe 

ring 

Darja 

flowering 


Domestic 

flowering 

Čebe 

-lica 

ripen 

ing 

Darja 

ripen 

-ing 

Che 

ck 

LSD 

0.05 

63.0 44.3 50.5 40.8 - - 40.5 - - 51.3 7.64 9.33 

1.83 1.18 - - 1.33 - - 1.15 - - 1.38 - - 1.90 0.38 0.47 

3.03 - - 3.38 - - 3.70 - - 3.48 - - 3.68 - - 4.33 0.49 0.60 

50%-extract of buckwheat suppresed germination of R. 

crispus too, but all cultivars in the flowering stage did not reduced 

the sprout number of investigated weed. 

LSD 

0.01 

66


Fig. 1-3. Effect of buckwheat cultivar extracts on the germination of R. crispus 

67


Fig. 4. Effect of buckwheat Domestic population 

Fig. 5. Effect of two buckwheat varieties extracts on G. aparine germination 

68


Table 8. The influence of 50% buckwheat extract on Galium molugo seed 

germination 

Traits 

Sprout 

number 

Root 

lenght 

Sprout 

lenght 


Čebelica 

ja tic lica ja 

Dar- Domes- 

Čebe- 

Dar- 

Check 

0.05 0.01 

LSD LSD 

flowerinrinrinining 

flowe- 

flowe- 

ripen- 

ripen- 

23.0 - - 27.5 - - 28.0 - - 29.8 - - 27.3 - - 42.5 8.22 10.04 

0.52 - - 0.88 - - 0.90 - - 0.93 - - 1.35 - - 1.78 0.28 0.34 

1.65 - - 2.65 - - 3.33 2.85 - - 2.90 - - 4.03 0.74 0.91 

All cultivars significantly reduced germination of G. molugo. 

Table 9. The influence of 100% buckwheat extract on Abutilon theoprasti 


Traits 

Sprout 

number 

Sprout 

lenght 


Čebe-lica 

Flowering 

Domestic 

flowering 

Čebelica 

ripen-ing 

Darja 

ripening 

Che 

ck 

LSD 

0.05 

LSD 

0.01 

11.8 - - 23.8 21.5 - 8.3 - - 26.0 3.95 5.54 

0.48 - - 1.18 - - 0.90 - - 0.65 - - 3.68 0.68 0.95 

The extract significantly inhibited the seed germination of A. 

theophrasti. 

These results confirmed the possible allelopathic effect of buckwheat 

on the tested weed species. 

According to Golisz et al. (2002), during buckwheat growth, 

buckwheat is effective in suppressing many weeds, including Agropyron 

repens. Weed biomass during buckwheat growth has been reduced by 75% 

(Iqbal et al., 2003; Tominaga and Uezu, 1995) and 86% (Creamer and 

Baldwin, 2000). Such reductions in weed biomass help prevent 

establishment of perennial weeds, as well as reduce the risk of seed 

production by summer annuals. In the absence of buckwheat, weeds that 

produce seeds rapidly (e.g., hairy galinsoga [Galinsoga ciliata (Raf.) Blake] 

) can add large quantities of seeds to the soil (Kumar et al., unpublished 

data). Even weeds that produce seeds more slowly are easier to kill after 

buckwheat cover cropping than they would be in the absence of this crop. 

69


According to Jensen and Helgeson (1957), buckwheat was cited as 

being a useful crop for the control of many weeds, including quackgrass, 

Canada thistle, sowthistle, creeping jenny, leaf spurge, Russian knapweed, 

and perennial pepper grass. 

Iqbal et al. (2002) showed that root exudates from buckwheat 

suppressed root and shoot growth of Trifolium repens, Brassica juncea, 

Amaranthus palmeri, Echinochloa crus-galli, and Digitaria ciliaris. 

Because buckwheat germinates quickly, it produces a dense canopy 

quickly, shading the soil and acting as a good competitor against weeds. 

Utilizing residue allelopathy as a management tool may be one of the 

more readily applicable uses of allelopathy in agroecosystems. Of all the 

possible strategies involving allelopathy for weed control, management of 

selectively toxic plant residues is the most successful, effective and readily 

available (Lovett, 1990). Management methods might include incorporating 

allelopathic crops in crop rotation, applying phytotoxic mulches, and cover 

cropping with allelopathic plants or smother crops. 

Conclusions 

In the field investigations, buckwheat reduced total weed biomass 

compared with plots without any crop. Total weeds number and mass were 

reduced for 46.2 and 53.4 by Čebelica, and for 46.3 and 37.1 by Darja, 

respectively. 

Amaranthus retroflexus and Hibiscus trionum were not inhibited by 

buckwheat in high percent. In the second evaluation, the number and mass of 

Amaranthus retroflexus were reduced for 40.7 and 31.8 by Čebelica and 47.4 

and 37.5 by Darja, respectively. 

In laboratory studies, water extract of buckwheat cultivars in 

flowering stage suppressed root and shoot growth and germination of Rumex 

crispus, Galium molugo, and Abutilon theophrasti, while the influence on 

sprout number of Galium aparine was lower. 

References 

CHOU, CH., 1999. Roles of allelopathy in plant diversity and sustainable agriculture. Crit. 

Rev. Plant Sci. 18, 609-636. 

CREAMER, N.G., K. R. BALDWIN, 2000. An evaluation of summer cover crops for use 

in vegetable production systems in North Carolina. Hort. Science. 35: 600–603. 

EINHELLIG, F. A., 1996. Interactions involving allelopathy in cropping system. Agron. J. 

88, 886-893. 

GOLISZ, A., D. CIARKA, S. W. GAWRONSKI, 2002. Allelopathy activity of buckwheat 

(Fagopyrum esculentum Moench). 161 in Fujii Y., Hidarate S., Araya H. Proc. III 

World Con. on Allelopathy. Tsukuba City, Ibaraki, Japan: Sato Printing. 

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HARAMOTO, E.R., E. R. GALLANDT, 2005. Brassica cover cropping: II. Effects on 

growth and interference of green bean (Phaseolus vulgaris) and redroot pigweed 

(Amaranthus retroflexus). Weed Sci. 53: 702-708. 

HIRADATE, S., S. MORITA, H. SUGIE, Y. FUJII, 2004. Phytotoxic cis-cinnamoyl 

glucosides from Spiraea thunbergii. Phytochemistry 65, 731-739. 

IQBAL, Z., S. HIRADATE, A. NODA, S. ISOJIMA, Y. FUJII, 2002. Allelopathy of 

buckwheat: assessment of allelopathic potential of extract of aerial parts and 

identification of fagomine and other related alkaloids as allelochemicals. Weed 

Biol. Manag. 2, 110-115. 

IQBAL, Z., S. HIRADATE, A. NODA, S. ISOJIMA, Y. FUJII, 2003. Allelopathic activity 

of buckwheat: isolation and characterization of phenolics. Weed Sci. 51: 657-662. 

ISOJIMA, S., Z. IQBAL, A. KOIZUMI, Y. FUJII, 2000. Allelopathy of Fagopyrum 

esculentum: Analysis of allelochemicals. J. of Weed Sci. Technol. 

Abbrev.(supplements in Japanese) 45, 92-93. 

JENSEN, L.A., E.A. HELGESON, 1957. Perennial weed control. Revised ed. N. Dak. 

Agric. Coll. Ext. Serv. Circ. A-194. 4 pp. Lovett, J.V. 1990. In "Alternatives to the 

Chemical Control of Weeds." Ed. by C. Bassett, L.J. Whitehouse and J.A. 

Zabkiewicz. Rotorua, New Zealand. pp.57-65. 

RICE, E. L., 1979. Allelopathy. An update. Bot. Rev. 45, 15-109. 

SHILLING, D.G., R. A. LIBEL, A. D. WORSHAM, 1985. Biochemical interaction among 

plants. In: The chemistry of allelopathy: (ed. by A. C. Thompson) ACS Symp. 

Series 268 American Chem. Soc., Washington D C, pp. 243-271. 

TOMINAGA, T., T. UEZU, 1995. Weed suppression by buckwheat: pp. 693–697 in T. 

Matano and A. Ujihasa, eds. Current Advances in Buckwheat Research. Volume 2. 

Proc. of the 6th Inter. Symp. of Buckwheat. Nagano, Japan: Shinshu University 

Press. 

WESTON, L.A., 1996. Utilization of allelopathy for weed management in agro ecosystems. 

Agron. J. 88, 860-866. 

71

Herbologia Vo. 9, No. 2, 2008. 

LONG-TERM EFFECTS OF SOIL TILLAGE ON WEED POPULATIONS 

IN WINTER WHEAT 

Mira Knežević, Bojan Stipešević, Ljubica Ranogajec, Ivan Knežević 

Faculty of Agriculture J. J. Strossmayer, University in Osijek, 

Trg sv. Trojstva 3, 31000 Osijek, Croatia 

e-mail: Mira.Knezevic@pfos.hr 

Abstract 

Field experiments were conducted in winter wheat on lessive 

pseudogley soil in northeastern Croatia from 1997 to 2006. The objective of 

this long-term study was to evaluate the effects of three tillage systems 

(conventional - mouldboard plow, CT; chisel plow, CP; disk harrow, DH) 

upon species composition, weed density, and weed dry weight, not using 

herbicides, as useful information to improve integreated weed management 

in cereal crops. 

Annual broad-leaved weeds dominated with 24 species compared 

with 11 perennials and 3 annual grasses. Weed species which occured in all 

three tillage systems at more than one shoot m -2 were: Ambrosia artemisiifolia 

L., Chenopodium album L., Galium aparine L., Matricaria inodora L., 

Polygonum aviculare L.; Calystegia sepium (L.) R. Br., Convolvulus arvensis L. 

Equisetum arvense L. Cirsium arvense (L.) Scop. and Apera spica-venti (L.) PB. 

Annual broad-leaved weed density in the CT system was statistically similar to 

that in the DH system in 7 out of 9 years. M. inodora tended to have higher 

populations in the DH system, especially in wet seasons of 2002 and 2004. C. 

album showed high variations among years and tillage systems, but it had the 

highest populations in the DH system during the drought season of 2003. P. 

aviculare showed a marked and statistically significant response to CT system, 

whereas A. artemisiifolia's response to tillage was not consistent. Most annual 

species including grass species of A. spica-venti were not favoured by any tillage 

system. Annual broad-leaved weeds comprised 63%, 50% and 41% of total 

dry weight in CT, CP and DH tillage systems, whereas perennial weeds 

comprised 3%, 26% and 44%, respectively. Reduced CP and DH tillage 

systems increased density and dry weight of some perennial weed species 

which associated with these tillage systems. C. arvense was the most important 

perennial weed on disk harrowed plots, after three years of experiment. 

Keywords: winter wheat, soil tillage systems, weed species, weed density, weed dry weight 

Introduction 

Soil tillage for cereal crops in Croatia is mainly conventional based 

on deep mouldboard ploughing as the primary soil operation. In recent years

M. Knežević et al. 

there has been a tendency towards less intensive soil tillage systems such as 

reduced, minimum or non-tillage as alternative to conventional tillage 

because of environmental and economical reasons. 

The introduction of new tillage practices can have a major impact on 

the species composition and density of weed populations that has been 

documented for cereal crops under different climatic and soil conditions in 

numerous reviews (Froud-Williams et al., 1981; Arshad et al., 1994). These 

tillage systems may increase the potential for growth of certain weed species 

due to weed seed accumulation at or near the soil surface (Wrucke and 

Arnold, 1985). 

A recent method of weeds control is based upon integrated weed 

management system. It includes a combination of cultural, mechanical, 

biological, genetic, and chemical measures for an effective and economical 

weed control in which the impact of weeds on crop yield is insignificant 

(Swanton and Weise, 1991). In their opinion, weed communities that evolve 

as a result of adaptation of such practices are not more difficult to control 

than those associated with conventional tillage systems. 

Crop production, its advantages and risks according to integrated cropping 

management system has not yet been sufficiently researched in Croatia, 

especially for main arable crops. Previous researches suggested that weed 

levels in some less intensive tillage systems for winter wheat, spring barley 

and maize with reduction of herbicide rates were comparable to conventional 

tillage (Knežević et al., 2003a, 2003b, 1999). An understanding of the longterm 

effects of reduced tillage systems on weed populations will provide 

useful information to improve integreated weed management in cereal crops. 

The objective of this study was to evaluate the long-term effects of three 

tillage systems upon weed species composition, weed density, and weed dry 

weight in winter wheat crop grown continuously on a lessive pseudogley soil 

without using herbicides. 


Field experiments with winter wheat (cv. Demetra) were conducted at 

Čačinci locality in the north-eastern part of Croatia. Soil type was lessive 

pseudogley: 13-18% of clay, 1.03% of organic matter, pH in H 2 O - 5.1, pH 

in nKCl - 4.1, 9.7 mg P 2 O 5 and 18.7 mg K 2 O 100 g -1 (Al-method). The 

fertilization was included 231 kg N, 150 kg P 2 O 5 and 100 kg K 2 O per ha. 

Top dressing by N was accomplished at the tillering stage in March. Tillage 

experiments were set up in the autumn of 1996 for winter wheat in 

wheat/maize rotation in 1996/1997, 1997/1998, 1999/2000, and in 

wheat/soybean rotation from 2000/2001 to 2005/2006. In March 1999 spring 

barley following maize was sown on the same plots instead of wheat, which 

74

Long-term effects of soil tillage on weed populations of buckwheat 

could not be sown due to the wet autumn of 1998. The weather data for each 

year are presented in the Table 1. 

Table 1. Monthly average air temperature and total precipitation during the 

winter wheat growing seasons (October-July) of 1996/1997 – 2005/2006 

M o n t h 

Total 

X. XI. XII. I. II. III. IV. V. VI. VII. Mean 

1996-1997 P 

T 

46 

12.1 

75 

8.5 

53 

-0.4 

15 

-1.3 

44 

4.9 

21 

6.6 

62 

8.9 

59 

17.0 

120 

20.4 

116 

21.1 

611 

9.8 

1997-1998 P 

T 

79 

9.4 

53 

6.2 

96 

3.0 

106 

3.8 

2 

6.1 

49 

5.2 

65 

12.7 

122 

16.1 

39 

21.8 

73 

22.1 

684 

10.6 

1999-2000 P 

T 

24 

14.4 

125 

4.6 

97 

2.1 

14 

-0.4 

23 

5.1 

39 

7.2 

60 

14.5 

37 

17.9 

37 

20.9 

87 

21.3 

543 

10.8 

2000-2001 P 

T 

53 

13.7 

46 

10.5 

46 

3.2 

85 

4.6 

20 

-0.7 

107 

9.5 

70 

9.6 

25 

17.0 

243 

17.7 

72 

21.6 

767 

10.7 

2001-2002 P 

T 

22 

14.7 

106 

-0.5 

37 

-3.4 

8 

0.5 

44 

5.3 

33 

6.4 

128 

10.9 

152 

18.5 

41 

21.1 

71 

22,7 

642 

9.6 

2002-2003 P 

T 

60 

11.8 

49 

9.6 

27 

1.6 

85 

-1.8 

15 

-3.1 

9 

6.6 

14 

10.9 

24 

19.7 

65 

23.7 

37 

22.8 

385 

10.2 

2003-2004 P 

T 

128 

9.8 

55 

8.0 

30 

1.4 

71 

-0.9 

64 

2.3 

52 

5.0 

127 

11.5 

76 

15.1 

98 

19.7 

68 

21.5 

769 

9.3 

2004-2005 P 

T 

121 

13.7 

143 

6.3 

47 

0.5 

40 

0.6 

75 

-2.7 

43 

6.5 

89 

11.2 

70 

16.0 

99 

19.0 

113 

20.9 

840 

9.2 

2005-2006 P 

T 

13 

11.9 

24 

5.4 

98 

2.5 

34 

-3.2 

44 

2.8 

66 

10.1 

94 

12.3 

90 

16.2 

87 

19.9 

27 

23.5 

577 

10.1 

P-precipitation (mm), T-temperature ( o C) 

The experimental design was a split-plot with tillage as the main 

plots and weed management as the sub-plots. Three tillage systems which 

performed continuously from 1996 were: CT-conventional (ploughing with 

mouldboard plough at 30-35 cm depth; CP- loosening with a chisel plough at 

15-20 cm depth; DH - disk harrowing at 8-10 cm depth. Weed control plots 

(9 x 3.5 m) included controls without herbicides and different herbicides 

applied post-emergently. The herbicide programs and results of the herbicide 

effectiveness in weed controlling were discussed in previous studies 

(Knežević et al., 2003a; Knežević et al., 2008). Winter wheat was 

mechanically harvested each year in the middle of July. The yield data were 

recorded and adjusted to 14% of the moisture content. 

The data of weed populations presented in this paper are based on the 

second weed assessment made on the untreated control plots in June of each 

season, at the wheat heading stage of. Weed densities were assessed in each 

treatment by counting the number of weeds in the sixteen 50 by 50 cm 

squares in each plot. Weeds found in each square was cut at ground level, 

separated by species, counted, oven-dried at 65 o C and weighed. Weed 

species were grouped to cycle life groups of annual grasses, annual broadleaved 

weeds and perennial weeds. 

75


Before the statistical analysis of variance the data were subjected to 

normality test, square root transformation had been performed for weed 

density only. For ANOVA the split-split-plot design was used, with year as 

the main factor, tillage as the sub-factor and weed management as the subsub-factor. 

The SAS V8.1 statistical package Proc Mixed was used for 

calculating ANOVA and means were separated using Fisher´s Protected LSD 

test at the 0.05 level of significance. 

Results and disscusion 

A total of thirty-eight weed species, 34 dicotyledons, three monocotyledons 

(Apera spica-venti (L.) PB., Bromus sterilis L., Echinochloa crus-galli (L.) 

PB.) and one pteridophyte (Equisetum arvense L.) were recorded in winter 

wheat on the two sampling dates during nine seasons. Annual broad-leaved 

weeds dominated with 24 species, compared to 11 perennial species and 3 

annual grass species. 

In the middle of April, when the wheat was mainly at the jointing stage 

(tillering stage only in 1997 and 2003) weed flora was dominated by autumn 

emerging species such as Capsella bursa-pastoris (L.) Med., Lamium 

purpureum L., Lathyrus tuberosus L., Raphanus raphanistrum L., Stellaria 

media (L.) Vill. and Veronica hederifolia L. At the same time populations of 

A. spica-venti (L.) PB., Galium aparine L. and Matricaria inodora L., more 

than one shoot per m 2 , emerged in all tillage stage treatments. A total dry 

weight of weed populations at the jointing stage of wheat was generally low, 

and it ranged on average from 1.06 g m -2 to 3.45 g m –2 . As the competition of 

weed species against wheat in the early spring was generally low, further 

analysis is focused on the weed populations at the heading stage of wheat. 

The time after wheat heading is the most important period because the weeds 

become strong competitors with wheat (Klem and Vánová, 1999). 

Ten species were found in all three tillage systems in numbers of more than 

one shoot m -2 in at least five of nine years. They were: annual broad-leaved 

species of Ambrosia artemisiifolia L., Chenopodium album L., G. aparine L., M. 

inodora L., Polygonum aviculare L., perennial species of Calystegia sepium (L.) 

R. Br., Convolvulus arvensis L., Equisetum arvense L. Cirsium arvense (L.) Scop. 

and grass species of A. spica-venti (L.) PB. In June these weed species constituted 

84% and 95% of total weed density and total weed dry weight, respectively 

(averaged over all tillage systems and years). Average density and dry weight for 

each weed species are shown in Table 5. 

76


Effect of tillage on weed density 

The effect of tillage on annual broad-leaved weed density was inconsistent 

and varied among years (Table 2). For example, in 1997 annual broad-leaved 

populations gathered 87% of the total weed density in the CT system where they 

were the most important weeds in the initial year. In 1998, densities of annual 

broad-leaved weeds were similar in the both CT and DH tillage systems, but were 

higher than in the CP system. In 2000 annual broad-leaved weeds comprised more 

than 70% of the total density in the DH system, whereas in the CT and CP 

systems, densities of these weed groups were similar, but averaged fivefold lower 

than in the DH system. However, after the fourth year, annual broad-leaved weeds 

showed a trend towards a lesser number of populations and density was similar 

among the three tillage systems in the last four years of experiment. 

Grassy annuals were only presented by A. spica-venti in densities 

higher than one plant per m 2 . Within the time frame of this study, no significant 

effect of tillage could be detected in density and dry weight of A. spica-venti 

(Table 2). However, there was a tendency to a lower shoot density under the 

reduced DH system during the dry period of 1997 and 2003, compared to the 

higher density in the wet Spring of 2004. In general, A. spica-venti showed 

little competitive ability in all three tillage systems. 

The tillage effects on perennial weeds were best expressed in the DH 

system in which perennial populations were significantly higher in 8 out of 9 

years compared to CT system. In the nine-year average, the densities of 

perennial populations were six-fold and four-fold higher in reduced DH and 

CP systems, respectively, than in the CT system (Table 4). Proportions in 

perennial densities in CT, CP and DH systems were 7%, 25% and 29% of the 

total weed density, respectively, with statistically differences. These results 

are in agreement with other studies that documented an increasing of 

perennial weed densities in reduced or no tillage systems in relation to 

conventional tillage system (Froud-Williams et al., 1981; Légère et al., 1990; 

Arshad et al., 1994). Légère et al. (1993) reported that perennial weeds in 

spring barley are not an exclusive problem of conservation tillage systems, 

but that it can develop in any tillage systems if conditions are appropriate. 

Table 2. Tillage effects on weed density (shoots m -2 ) of weed groups in 

winter wheat under the three tillage systems 

Tillage 1997 1998 2000 2001 2002 2003 2004 2005 2006 

Annual 

grasses 

CT 5 a 3 a 5 a 2 a 3 b 3 a 9 a 7 a 7 a 

CP 0 b 2 a 4 a 1 a 11a 1 a 11 a 8 a 9 a 

DH 0 b 4 a 6 a 2 a 1 b 1 a 9 a 8 a 6 a 

77


Annual CT 40 a 17 a 5 b 7 a 12 a 9 a 6 a 9 a 7 ab 

broadleaved 

CP 16 c 5 c 9 b 2 b 14 a 10 a 10 a 9 a 5 b 

DH 24 b 14 a 35 a 3 ab 12 a 13 a 7 a 7 a 9 

a 

Perennial 

CT 1 a 3 c 1 b 2 b 1 b 0 b 1 b 2 b 1 b 

CP 2 a 7 b 7 a 5 a 4 a 2 b 8 a 4 ab 3 b 

DH 2 a 15 a 8 a 5 a 6 a 5 a 9 a 7 a 8 a 

Total CT 46 a 22 b 11 c 11 a 16 b 12 b 16 b 18 a 15 b 

CP 18 c 14 c 20 b 8 a 29 a 13 b 29 a 21 a 17 b 

DH 26 b 33 a 49 a 10 a 19 b 19 a 25 a 22 a 23 a 

Comparisons are between tillage systems within years and within weed groups; tillage 

means followed by the same letter are not significantly different at P < 0.05. CT – 

mouldboard ploughing; CP – chisel ploughing; DH – disk harrowing 

Table 3. Tillage effects on weed dry weight (g m -2 ) of weed groups in winter 

wheat under the three tillage systems 

Tillage 1997 1998 2000 2001 2002 2003 2004 2005 2006 

Annual 

grasses 

CT 0.8 a 1.7 a 3.6 a 8.0 a 10.0 

a 

1.6 a 28.0 

b 

CP 0 a 1.9 a 2.6 a 2.1 c 10.8 0.1 a 36.1 

a 

a 

DH 0 a 2.2 a 2.2 a 4.6 b 2.8 b 0.4 a 29.1 

b 

10.4 

c 

18.0 

b 

22.4 

a 

22.4 

b 

20.8 

b 

25.9 

a 

Annual 

broadleaved 

CT 13.8 

a 

CP 6.8 

a 

DH 12.0 

a 

5.6 a 2.7 

b 

7.2 a 25.9 

a 

3.8 a 21.1 

a 

18.7 

a 

8.7 

b 

11.9 

ab 

30.4 

a 

36.8 

a 

29.2 

a 

2.1 b 27.6 

b 

8.2 30.0 

ab b 

14.0 58.2 

a a 

27.2 

b 

33.4a 

b 

40.0 

a 

28.1 

b 

34.4 

b 

52.2 

a 

Perennial 

CT 0.4 a 0.8 b 1.0 c 2.4 b 0.8 

c 

CP 3.2 a 5.4 8.7 b 17.7 12.6 

ab 

a b 

DH 1.6 a 10.8 32.2 19.2 56.5 

a a a a 

0.1 b 0.9 

c 

1.5 b 15.7 

b 

24.7 37.4 

a a 

0.5 c 0.4 

c 

17.6 16.4 

b b 

44.5 34.1 

a a 

Total 

CT 15.0 

a 

CP 10.0 

a 

8.1 

a 

14.5 

a 

7.3 c 29.1 

a 

37.2 28.5 

b a 

41.1 

c 

60.3 

b 

3.7 b 56.5 

c 

9.8 b 81.8 

b 

38.1 

c 

69.0 

b 

50.9 

c 

71.7 

b 

78


DH 13.6 

a 

16.8 

a 

55.5 

a 

35.7 

a 

88.5 

a 

39.0 

a 

124.7 

a 

106.9 

a 

112.3 

a 

Comparisons are between tillage systems within years and within weed 

groups; tillage means followed by the same letter are not significantly 

different at P < 0.05. 

Table 4. Tillage effects on weed density (shoots m -2 ) and weed dry weight (g 

m -2 ) of weed groups under the three tillage systems (averaged over nine 

years) 

Weed groups 

Annual broadleaved 

Tillage 

Weed 

density 

(shoots m -2 ) 

Weed dry 

weight (g m - 

) 

CT 12.5 ab 17.36 b 

CP 8.7 b 21.27 ab 

DH 13.7 a 26.93 a 

Perennial CT 1.2 c 0.81 c 

CP 4.7 b 10.98 b 

DH 7.1 a 29.00 a 

Annual grasses CT 4.9 a 9.60 a 

CP 5.1 a 10.27 a 

DH 4.0 a 9.96 a 

Total CT 18.6 b 27.77 c 

CP 18.5 b 42.52 b 

DH 24.8 a 65.89 a 

Tillage means followed by the same letter are not significantly different 

at P < 0.05. 

A large number of annual broad-leaved populations, which was found 

in CT in the first initial year of our experiment, probably reflected the effect 

of soil disturbance by mouldboard ploughing on the seed-bank composition 

and seedling distribution in the soil layer. Frick and Thomas (1992) found a 

higher density of annual and lower density of perennial species in 

conventional than in the reduced tillage. Other studies reported that the 

reduced tillage increased the density of perennial weeds and some annual 

grasses (Derksen et al., 1993; Blackshaw et al., 1994). However, in some 

cases, tillage has no selective effect on weed flora (Swanton et al., 1993). 

Contradictory results have often been presented in regards to changes in 

weed community composition that was influenced more by the location and 

year than by tillage systems, indicating fluctuated rather than consistent weed 

community changes (Derksen et al., 1993; Swanton et al., 1993). 

79


Effect of tillage on weed dry weight 

Total weed dry weight varied between years considerably. The 

highest weed dry weight across all tillage treatments was found in the first 

year of 1997, whereas the lowest was found in 2003 (Table 3). In the 

extremely dry season of 2003 (Table 1), when precipitation from October to July 

was 261 mm less than the average of 646 mm in 1997-2006, total weed dry 

weight was decreased by 93%, 86% and 63%, on average in CT, CP and DH 

tillage systems, respectively, compared to the extremely wet season of 2004. 

In respect of tillage, total weed dry weight was the highest in the DH 

system and the lowest in the CT system, ranging from 65.89 g to 27.77 g m -2 , 

with significant differences (Table 4). Tillage affects the dry weight of 

annual broad-leaved and perennial weeds. The proportions of annual broadleaved 

dry weight were 63%, 50% and 41% in CT, CP and DH tillage 

systems, whereas proportions of perennials dry weight were 3%, 26% and 

44%, respectively. Significant differences in dry weight between the three 

tillage systems were detected in 2000, when the perennial dry weight in DH 

and CP systems were 32-fold and 9-fold higher, respectively, compared to 

CT system. The tendency of perennial biomass increase on these disk 

harrowed plots after only two years of experiment was reported previously 

(Knežević et al., 2003a). 

Effect of tillage on individual weed species 

Some responses of individual species to tillage treatments could be 

identified (Table 5). For example, perennial species of C. sepium, C. 

arvensis, E. arvense and C. arvense produced a higher number of 

populations and dry weight in the DH and CP systems than in the 

conventional tillage system. Other perennial species such as Plantago major, 

Rumex obtusifolius, Sonchus arvensis, Symphytum officinale, and Sonchus 

arvensis associated also mainly with DH tillage but with low densities. 

C. arvense was the most important perennial species on disk 

harrowed plots. This was evident in 2000, when C. arvense was more 

frequent than three years before (including spring barley on the same plots in 

1999). Futhermore, in the wet season of 2002, four shoots m -2 of C. arvense 

in DH tilled plots produced 47.8 g m -2 or 84% of the total perennial dry 

weight. According to Mclennan et al. (1991) C. arvense has a strong 

competitive effect on winter wheat and grain yield is closely related to the 

number of it shoots. These authors demonstrated yield losses of 

approximately 50% corresponding to C. arvense densities of 38 shoots per 

square meter. 

80


Most summer annual broad-leaved species found in our study showed 

a less marked response to any tillage system. Only P. aviculare showed a 

marked and statistically significant response to the conventional tillage with a 

higher number of populations in this tillage system than in the other two 

reduced systems. 

Table 5. Tillage effects on density (shoots m -2 ) and dry weight (g m -2 ) of 

main weed species in winter wheat (1996/97 – 2005/06) 

Weed species 

Tillage 

Weed density 

shoots m -2 

Weed dry 

weight g m -2 

Annual broad-leaved 

Ambrosia artemisiifolia L. CT 4.2 ab 1.76 a 

CP 1.2 b 0.56 b 

DH 5.0 a 1.52 a 

Matricaria inodora L. CT 1.9 a 9.04 b 

CP 1.4 a 10.00 b 

DH 1.5 a 16.80 a 

Chenopodium album L. CT 2.4 a 0.76 ab 

CP 1.8 a 0.52 b 

DH 3.1 a 1.56 a 

Galium aparine L. CT 0.6 a 4.88 b 

CP 1.1 a 8.64 a 

DH 0.7 a 4.72 b 

Polygonum aviculare L. CT 1.2 a 0.32 a 

CP 0.1b 0.08 a 

DH 0.3b 0.40 a 

Perennial 

Equisetum arvense L. CT 0.7 b 0.32 b 

CP 1.8 a 3.72 a 

DH 2.1 a 2.88 a 

Calystegia sepium (L.) 

R.Br. 

CT 0.1 b 0.12 b 

CP 0.8 b 2.40 a 

DH 1.3 a 2.60 a 

Convolvulus arvensis L. CT 0.3 b 0.32 b 

CP 1.3 a 2.12 a 

DH 1.4 a 2.64 a 

81


Cirsium arvense (L.) Scop. CT 0 b 0 b 

CP 0.1b 2.44 b 

DH 1.8 a 18.56 a 

Annual grasses 

Apera spica-venti (L.) PB. CT 4.9 a 9.60 a 

CP 5.1 a 10.20 a 

DH 4.0 a 10.00 a 

Density and dry weight means for a weed species in each column, followed 

by the same letter, are not significantly different at P < 0.05. 

Other species, which are not included in the statistical analysis due to 

a low density (less than one plant m -2 ) were: Anagallis arvensis L., Capsella 

bursa-pastoris (L.) Med., Chenopodium polyspermum L., Cerastium 

glomeratum Thuill., Echinochloa crus-galli (L.) PB., Erigeron annuus (L.) 

Pers., Fallopia convolvulus (L.) Á. Löve, Gnaphalium uliginosum L., 

Gypsophila muralis L., Lamium purpureum L., Lathyrus tuberosus L., 

Lythrum hyssopifolia L., Lythrum salicaria L., Oxalis fontana Bunge, 

Plantago major L., Polygonum lapathifolium L. Ranunculus sardous Cr., 

Raphanus raphanistrum L., Rumex obtusifolius L., Senecio vulgaris L., 

Sonchus arvensis L., Sonchus asper (L.) Hill., Stachys annua (L.) L., Stachys 

palustris L., Stellaria media (L.) Vill., Symphytum officinale L., Veronica 

hederifolia L.and Viola arvensis Murray. 

This finding does not concur with our previous research results 

(Knežević et al., 2003a ) but it is consistent with other researches that 

showed a density increase of P. aviculare with increased levels of 

cultivations (Pollard et al., 1982; Derksen et al., 1993). 

C. album was a highly variable among years and tillage systems. The highest 

density of 8 shoots m -2 or 60% of the total density was found under disk 

harrowed plots in the drought season of 2003, when C. album populations 

increased threefold compared to the conventional tilled plots. In contrast, the 

lowest densities (only 0.25 shoot m -2 ) were found in the wet seasons of 2002 

and 2004 in all three tillage systems. 

Environmental conditions, degree of soil disturbance between 

compared tillage systems and the ability of C. album to germinate at smaller 

depths may have contributed to the large variations in plant density. 

Response of C. album to tillage was discussed in several studies (Froud- 

Williams et al., 1981; Blackshaw et al., 1994; Bàrberi and Bonari, 2008) 

which noted an association between C. album and CT system. However, in 

some cases populations of C. album increased in conservation tillage systems 

(Thomas and Frieck, 1993) or were not influenced by tillage (Roman et al., 

1999). Variations in C. album seedlings were attributed to the interaction of 

82


tillage with environmental conditions, soil temperature and moisture (Roman 

et al., 1999). 

A. artemisiifolia was one of the most frequent weed species on the 

field plots, which emerged at the end of April and the beginning of May. In 

2000 A. artemisiifolia produced a large number of 25 plants m -2 on disk 

harrowed plots, which was sevenfold higher than in those found in the CT 

system. A significant interaction between tillage and shoot densities was 

detected in 2000. In other years there was no detectable clear influence of 

tillage in the number of A. artemisiifolia populations. A. artemisiifolia seeds 

germinate mostly from the 2.6 to 3 cm soil layers (Kazinezi et al., 2008). 

That may have contributed to the tillage effect caused by disk harrowing in 

our study. 

M. inodora populations emerged in April (in May only in 2003) and 

were flowered mainly at wheat heading in June. M. inodora produced 

significantly higher biomass in the DH system but no significant differences 

in shoot density were found among three tillage systems. M. inodora 

populations thrived in DH tillage in the wet seasons of 2004 with total 

precipitation of 203 mm in April and May (Table 1), when they were strong 

competitors with wheat. On the disk harrowed plots in the absence of 

herbicides, M. inodora shoots attained of 0.5 to 1.1 m with the dry weight of 

46 to 104 g. However, in 2003, which was associated with hot, dry 

conditions, early in the growing season (total precipitation in April and May 

only 23 mm), it showed a biomass depression by 80%, compared to an 

average of 45.8 g m -2 in wet spring months. Blackshaw and Harker (1997) 

reported for the areas of Canadian prairies that scentless chamomile shoots 

produced more biomass with increasing amounts of precipitation. 

Most other weed species displayed considerable year-to-year variation in 

germination, as well as in population densities. 

Herbicide programs used in this study resulted in a successful 

reduction of density and dry weight of summer annual broad-leaved and 

grass weeds, but in an inadequate control of perennials (Knežević et al., 

2003a; Knežević et al., 2008). 

Tillage had significant effects on crop yield from plots without 

herbicides, ranging from 5.8 t in the CT to 5.2 t ha -1 in the DH system with 

significant differences. Chemical weed control increased crop yields in CT 

only in 2 out of 9 years, which corresponds to an increase of 2%, whereas 

significant average yield increases of 9% occured in both reduced CP and 

DH tillage systems, compared to yields from untreated control plots. No 

significant differences were found in yields from treated plots between CT 

and CP systems (5.9 t ha -1 ), whereas yield decrease in the DH system was 

3% compared to the same tillage systems with ploughing (data not shown). 

83


To sum up, weed species differences were found only in the DH tillage 

system, which was favourable for the development of most weed 

populations. In that way perennial species showed higher populations in 8 

out of 9 years, compared to CT system. Annual broad-leaved populations 

varied over time, but plant densities in the DH system were statistically 

similar to CT system in 7 out of 9 years. Grassy annual populations with 

main species of A. spica-venti showed an inconsistent response to tillage 

systems with a tendency to higher density in wet seasons in all three tillage 

systems. Annual variations in total weed density and weed dry weight were 

attributed to interaction of tillage and year. 

Acknowledgements: This work was supported by the Croatian Ministry of Science, 

Education and Sports ("Integrated arable crop protection from weeds"- 079-0790570-2716). 

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85


POSSIBILITIES OF REDUCED DOSES OF POST-EMERGENT 

HERBICIDES: PRELIMINARY RESULTS 

Svetla Maneva & Senka Deneva Milanova 

Plant Protection Institute, 2230 Kostinbrod, Bulgaria 

e-mail: sve_ma@yahoo.com 

Abstract 

The objectives of this study were to examine the possibility of 

reducing doses of mesosulfuron-methyl + iodosulfuron-methyl-natrium and 

clodinofop-propargyl in mixture with adjuvants. The pot experiments were 

carried out in greenhouse of Plant Protection Institute, Kostinbrod in 2007, 

with test plants of Avena fatua and Alopecurus myosuroides. 

Mesosulfuron+iodosulfuron was applied as a commercial formulation 

Atlantis WG, Bayer Crop Science (30 g/kg mesosulfuron-methyl + 6 g/kg 

iodosulfuron-methyl-natrium + 90 g/kg mefenpyr-diethyl) and clodinonafoppropargyl 

as a commercial formulation Topik 240 EC, Syngenta (240 g/l 

clodinafop-propargyl) in mixtures with adjuvants. A fraction-polynomial 

regression model with lg transformation of the dose was used to summarize 

the results. The results showed that inclusion of the adjuvant Biopower in the 

spray solution significantly improved the activity of mesosulfuron + 

iodosulfuron and allowed reducing the dose up to 50%. Reducing the 

application rate of clodinofop-propargyl by 50% in mixture with adjuvant 

Phase II was without any loss in efficacy. 

Keywords: reduced dose, Avena fatua, Alopecurus myosuroides, Atlantis WG, Topik 240 

EC, adjuvant 

Introduction 

Among the key grass species infesting cereals in Europe are: 

Alopecurus myosuroides, Apera spica-venti, Avena fatua, Lolium sp., and 

Phalaris sp. (Hofer, 2005). Avena fatua L. and Alopecurus myosuroides 

Hudson are the most economically important and widely distributed annual 

grass weed species in the world (Scragg et al., 1976; Farahbakhsh et al., 

1987; Wilson & Wright, 1990; Colbach & Chanvel, 2005; Viggiani, 2005; 

Gul Hassan et al., 2006; Page et al. 2007). In the last weed survey in 

Bulgaria (2004-2007) was established that the most problematic annual grass 

weeds in cereal crops were Avena fatua, A. sterilis ssp. ludoviciana (Dirieu)

S. Maneva and S. Deneva Milanova 

Gillrt & Magne and Alopecurus myosuroides Hudson (Nikolov et al., 2004, 

Milanova et al., 2007; Milanova et al., 2007). The increasing expansion of A. 

fatua and A. myosuroides was evident in the last decade. Infestation of these 

weed species in cereals is a major limitation to successful cereal production 

not only in Europe but around the globe as well (Chancellor & Fround- 

Williams, 1984; Hofer et al., 2005). Avena fatua L. is characteristic wild oat 

of the Great Britain and North West Europe, North America and other 

regions with similar climate (Thurston, 1976). There are a lot of 

investigations on the effectiveness of crop competition for better weed 

control and possibility to reduce of herbicide rates in cereals (Richards, 

1993; Stevenson et al., 2000; Walker et al., 2002; Vanaga, 2003; Maneva et 

al., 2005; Martinson et al., 2007). Milanova & Valkova (2007) reported that 

it is possible to reduce dose of metsulfuron-methyl. This fact is attributed to 

the competitive ability of spring barley crop also. Mixture of some herbicides 

with surfactant-adjuvants allowed for herbicide dose reductions up to 50% 

without negative effect on the yield of winter wheat (Hristov, G, 1996). 

Adjuvants may promote the uptake of herbicides but, on the other hand their 

presence on the leaf surface can increase the vulnerability of spray deposits 

to wash off by rain (Kudsk & Olesen, 1988; Mathiassen & Kudsk, 2002). 

Sulfonylureas (ALS inhibiting herbicides) are an important and widely used 

herbicide group against the widely spectrum of weed species. It is very 

important to know the possibilities to reduce the dose of widely used 

herbicides for grass weed control in cereal crops in mixture with adjuvant. 

The objectives of this study were to examine the possibility of 

reducing doses of mesosulfuron-methyl + iodosulfuron-methyl-natrium and 

clodinofop-propargyl in mixture with adjuvants, using the key grass species 

as biotest. 


Pot experiments were carried out at the Plant Protection Institute, 

Kostinbrod in 2007. Avena fatua and Alopecurus myosuroides were grown in 

the greenhouse at a day/night temperature of 25 o /18 o C under 16 h 

photoperiod provided by natural light. Seeds of these species were sown in 

1.5 L pots in sandy loam soil. The number of plants per pot was reduced to 

15 numbers after the emergence. The investigation was performed after the 

method of the EWRS working group “Optimization of herbicide dose” (notpublished) 

and adapted to greenhouse conditions. Mesosulfuron + 

iodosulfuron was applied as a commercial formulation Atlantis WG, Bayer 

Crop Science (30 g/kg mesosulfuron-methyl + 6 g/kg iodosulfuron-methylnatrium 

+ 90 g/kg mefenpyr-diethyl) and clodinonafop-propargyl as a 

88

Possibilities of reduced doses of post-emergent herbicides: preliminary results 

commercial formulation Topik 240 EC, Syngenta (240 g/L clodinafoppropargyl) 

in mixtures with adjuvants. 

Trial plans: 

a/ 1.Untreated; 2.Atlantis* WG 50 g/ha + Biopower 1 L/ha; 3.Atlantis WG 

100 g/ha + Biopower 1 L/ha; 4.Atlantis WG 200 g/ha + Biopower 1 L/ha; 

5.Atlantis WG 400 g/ha + Biopower 1 L/ha. 

b/ 1.Untreated; 2.Topik 240 EC 31.25 ml/ha + Phases II 1 L/ha; 3.Topik 240 

EC 62.5 ml/ha+ Phases II 1 L/ha; 4.Topik 240 EC 125 ml/ha + Phases II 1 

L/ha; 5.Topik 240 EC 250 ml/ha + 1 L/ha. 

* In the article will be used the name of commercial formulation for brief 

presentation. 

Three pot trials in five replications per treatments were carried out. 

Herbicides with adjuvants were applied at two growth stages (GS) of Avena 

fatua: 21-23 BBCH and 30-31 BBCH scale (Hess et al., 1997). The plants of 

A. myosuroides were treated at the 3 to 4 leaves stages. Herbicide activity 

was assessed by recording fresh weight of plants one month after spraying. 

Data were analyzed by non-linear regression. The dose response 

curves were developed by Non-linear estimation of the statistical software 

SATISTICA 5.0. The used estimation method was Quasi–Nuton with R 

values for fitting statistical significance of the regression models to the 

experimental data. 


Dose response curve: The usually used regression model for dose 

respond curves is that presented by Streibig et al. (1995). The case when this 

model gives good fitting to the experimental data is when the data have the 

S-behavior. The previous statistical estimation showed that in our case the 

data had not this characteristic. They were closer to the rectangular 

hyperbola. That why the better fitting to the data was obtained using the 

regression model (1) 

(1) Y=1/(A 1 +A 2 lg(I+X) 

where Y – fresh weight as % of the control, X – the applied doses of the 

respective herbicide, A 1 and A 2 – parameter of the regression model, and I – 

corrective coefficient. 

This model gives faster decreasing of the curve for the lower doses 

and slower decreasing for the higher. With varying of parameter I = 1, 10 or 

100 it could conduct the slope in the beginning of the curve. 

89


Estimation of the dose reduction: Phytotoxic effects were observed in the 

two studied species ranging from chlorosis, necrosis, inhibition of plant 

growth to death, depending on the doses of Atlantis WG in mixture with 

adjuvant. It was established that serious damage on Avena fatua at the 

growth stage 21-23 BBCH scale occurred at normal (full) dose of Atlantis 

WG (40 g/ha) and at ½ of normal dose. The reduction of fresh weight was 

67.4% and 65.7% respectively (Fig.1, A). Good effect of Atlantis WG at 

normal and ½ of normal dose was observed in growth stages of A. fatua 30- 

31 BBCH also. The reduction of fresh weight was 70.4% and 66.5%, 

respectively (Fig. 1, B). At these doses the plants of A. fatua did not reach 

to the inflorescence. The data showed that there is not any difference in 

efficacy of herbicide, applied at different growth stages of A. fatua. 

Martinson et al. (2007) also reported that mesosulfuron applied in reduced 

rates did not consistently resulted in less control of A. fatua. With increasing 

the doses of Atlantis WG the fresh weight of Alopecurus myosuroides at 

studied growth stage decreased (Fig. 1, C). Atlantis WG + adjuvant at 

normal and ½ of normal dose significantly affected plant growth. The 

reduction of fresh weight was 88.2% and 86.8%, respectively. Severe 

phytotoxic symptoms on A. fatua were recorded in two growth stages at full 

dose of Topik 240 EC + adjuvant and ½ of normal dose. The reduction of 

fresh weight of plants at 21-23 BBCH was 81.6%, 72.5% and at 30-31 

BBCH – 77.6%, 72.1%, respectively (Fig.2, A and B). A. myosuroides plants 

were injured significantly at normal dose of Topic 240 EK + adjuvant and ½ 

of normal dose. The reduction of fresh weight was 87.8% and 87.4%, 

respectively (Fig. 2, C). It was evident that with increasing the doses of 

Topik 240 EK + adjuvant the reduction of fresh weight of plants increased. 

90


F r e s h w e i g h t - % o f u n t r e a t e d 

B 

F r e s h w e i g h t - % o f u n t r e a t e d 

F r e s h w e i g h t - % of u n t r e a t e d 

110 

100 

90 

80 

70 

60 

50 

40 

30 

110 

100 

90 

80 

70 

60 

50 

40 

30 

A 

A v e n a f a t u a - in GS 30-31 BBCH 

y=1/(0.00999 + 0.0084.lg(1+x)), R = 0.996 +++ 

20 

0 50 100 150 200 250 300 350 400 

120 

100 

80 

60 

40 

20 


y=1/(0.00998+0.007lg(1+x)), R=0.997 +++ 

20 

0 50 100 150 200 250 300 350 400 450 

D o s e s o f A T L A N T I S WG - g/ha 


A l o p e c u r u s m y o s u r o i d e s 

y=1/(-0.14296 + 0.0764.lg(100+x)), R = 0.999 +++ 

0 

0 50 100 150 200 250 300 350 400 450 


C 

Figure 1. Effect of reduced doses of ATLANTIS WG + adjuvant on the fresh weigh of : 

A – Avena fatua in GS 21-23 BBCH; B – Avena fatua in GS 30-31 BBCH; 

C – Alopecurus myosuroides in GS 3-4 leaves 

91


F r e s h w e i g h t - % of u n t r e a t e d 

A 

110 

90 

70 

50 

30 


y=1/(-0.1437 + 0.0768.lg(100+x)), R = 0.997 +++++ 

10 

0 50 100 150 200 250 300 

D o s e s o f T O P I K 240 EC - ml/ha 

F r e s h w e i g h t - % of u n t r e t e d 

B 

F r e s h w e i g h t - % of u n t r e t e d 

110 

90 

70 

50 

30 


y=1/(-0.1497 + 0.0799.lg(100+x)), R= 0.995 +++ 

10 

0 50 100 150 200 250 300 

120 

100 

80 

60 

40 

20 

D o s e s o f T O P I K 240 EC - ml/ha 

Alopecurus myosuroides 

y=1/(-0.197 + 0.1036.lg(100+x)), R=0.977 +++ 

0 

0 50 100 150 200 250 300 

D o s e s of T O P I K 240 EC - ml/ha 

C 

Figure 2. Effect of reduced doses of TOPIK 240 EC + adjuvant on the fresh weight of: 

A – Avena fatua in GS 21-23 BBCH; B – Avena fatua in GS 30-31 BBCH; C – Alopecurus 

myosuroides in GS 3-4 leaves 

92


Conclusion 

The results showed that inclusion of the adjuvant Biopower in the 

spray solution significantly improved the activity of mesosulfuron + 

iodosulfuron and allowed reducing the dose up to 50%. Reducing the 

application rate of clodinofop-propargyl by 50% in mixture with adjuvant 

Phase II was without any loss in efficacy. 

Acknowledgements. We thank to Dr. Per Kudsk for the creation of the method for 

investigation of reduced dose and the firms Bayer Crop Science and Syngenta for supply of 

the herbicides.. 

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GUL HASSAN, YOUSAFZAI, H.K. 2006: Effect of wild oats (Avena fatua L.) density on 

wheat yield and its components under various nitrogen regimes. Herbologia, 7, 71- 

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HESS, M., BARRALIS, H., BLEIHOLDER, H., BUHR, L., EGGERS, TH., HACK, K., 

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HOFER, U., BUTEL, D., CAMPAGNA, C., GORROCHATEGUI, A., MILLS, C., 

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94


CHEMICAL WEED CONTROL IN STANDS OF RED CLOVER 

(Trifolium repens L.) IN THE YEAR OF THEIR ESTABLISHMENT 

Tsvetanka Dimitrova*, Plamen Marinov-Serafimov 

Institute of Forage Crops, 5800 Pleven, Bulgaria 

*E-mail: ifc@el-soft. com 

Abstract 

The possibility for chemical weed control in stands of red clover 

(Trifolium repens L.) in the year of their establishment was studied in the 

experimental field of the Institute of Forage Crops, Pleven, Bulgaria during 

the 2006-2007 period. For that purpose a field trial was carried out on 

slightly leached chernozem with prevailing participation of annual monoand 

dicotyledonous weeds. 

As a result of the study it was found that: The chemical weed control 

in the red clover stands in the year of their establishment was successful 

through application of the herbicides: Imazethapyr 100 a.i.l -1 – 100 ml a.i. ha - 

1 ; Imazamox 40 a.i.l -1 - 48 ml a.i. ha -1 ; Imazamox 40 a.i.l -1 – 40 ml a.i. ha -1 + 

DESH – 1000 ml ha -1 ; Bentazone 600 a.i. l -1 – 900 ml a.i. ha -1 ; Fluazifop-Pbutyl 

150 a.i.l -1 – 225 ml a.i. ha -1 applied at the two to four true leaf stage of 

the crop. The treatment with herbicides resulted in establishment of uniform 

stands with red clover participation of 85 to 94% in the sward and an 

increase of their dry biomass productivity by 44 to 66%. 

Key words: red clover, weeds, herbicides, productivity. 

Introduction 

Red clover is a perennial legume crop suitable for regions with a 

more humid climate and developing also on soils with increased acidity. It is 

close in nutritive value to lucerne, a good melliferous plant and, in addition, 

it exerts a favourable influence on soil fertility and is an excellent preceding 

plant for all crops (Yancheva, 2007). 

A biological feature of red clover characteristic, also of the other 

perennial legume crops, is its slow rate of growth and development after 

sowing, which causes its low competitiveness towards the weeds, 

particularly in the year of their establishment. 

The decrease of weed population density is most successful through 

combination of cultural practices with chemical method. In spite of the 

limited studies on this crop, some authors reported for herbicides possessing 

good selectivity and efficacy (Benkov and Dimitrova, 1983; Lyubenov et al., 

1987; COLUMA, 1973). In his studies, Prodanov (1980) and Rybak (1976)

Ts. Dimitrova and P. Marinov-Serafimov 

found that some herbicides (Kerb mix B, asulam, THA, 2,4-D, 2M-4H, 

bromoxynil) exerted a toxic effect on the crop. 

The herbicides will remain also in the future agriculture an efficient 

means of weed control, as an element of integrated management, so there is a 

need for studies to optimize their use (Kudsk and Streibig, 2003). 

The objective of this study was to investigate the effect of some 

herbicides for chemical weed control in the year of establishment of red 

clover stands. 


The study was conducted on the experimental field of the Institute of 

Forage Crops, Pleven on slightly leached medium-deep chernozem during 

the 2006-2007 period. The trial was laid out by the block method with a size 

of harvest plot of 10 m 2 in the following variants: V 1 – Check zero; V 2 – 

Check weeded; V 3 – Imazethapyr 100 a.i. l -1 – 100 ml a.i. ha -1 ; V 4 – 

Imazamox 40 a.i.l -1 - 48 ml a.i. ha -1 ; V 5 - Imazamox 40 a.i.l -1 – 40 ml a.i. ha - 

1 ; V 6 - Imazamox 40 a.i. l -1 – 40 ml a.i. ha -1 - + DESH – 500 ml a.i. ha -1 ; V 7 - 

Imazamox 40 a.i. l -1 – 40 ml a.i. ha -1 - + DESH – 1000 ml a.i. ha -1 ; V 8 - 

Bentazone 600 a.i. l -1 – 900 ml a.i. ha -1 – Fluazifop-P-butyl 150 a.i. l -1 – 225 

ml a.i. ha -1 . 

The herbicides were applied with a working solution of 400 l/ha -1 at 

the two to four true leaf stage of the crop. The following characteristics were 

observed in the study: herbicide selectivity (according to the EWRS methods 

with a 9-score scale, at score 1: no damages to the crop and at score 9: the 

crop is completely killed); herbicidal efficacy (by the quantity-weight 

method); productivity of dry biomass. 


The high natural background of weed infestation of the area reaching 

to a number of 615 per m 2 and the weed fresh biomass of 2268 g/m 2 

provided a possibility to evaluate the weed competitive effect on the crop 

growth and development, as well as the herbicidal efficacy of the products 

(Table 1). 

96

Chemical weed control in stands of red clover (Trifolium repens L.) in the year ... 

Table 1. Degree of weed infestation of red clover (average for 2006-2007) 

Weeds/m 2* V 1 V 2 V 3 

Variant ** 

V 4 V 5 V 6 V 7 V 8 

559 0 7 34 99 76 60 11 

Annual monocotyledonous 1298 13 48 194 154 91 25 

Setaria spp. 491 

1152 

4 

7 

22 

52 

60 

109 

55 

97 

43 

60 

6 

14 

Echinochloa crus galli L. 

68 3 11 32 21 17 5 

140 6 26 85 57 31 11 

Annual dicotyledonous 

42 10 15 16 12 15 11 

0 

940 83 110 143 114 73 567 

Senapis arvensis L. 

8 

1 

0 0 

582 

10 

0 0 0 

Amaranthus spp. 

20 

3 

5 4 4 4 3 

190 

15 

28 41 20 20 7 

Chenopodium album L. 

7 

5 6 6 5 3 4 

132 50 61 67 78 33 43 

Solanum nigrum L. 

7 

4 4 5 3 8 4 

36 18 21 25 21 20 17 

Perennial dicotyledonous 

12 6 3 7 6 4 7 

0 

30 9 6 15 11 8 11 

Convolvulus arvensis L. 

12 5 3 7 6 4 7 

30 9 6 15 11 8 11 

Total weeds 

615 22 52 115 94 79 29 

0 

2268 105 194 352 279 172 103 

Herbicidal efficacy, % - - 95 91 84 88 92 95 

*Weeds/ m 2 : in numerator – number; in denominator – g. 

**Variant: V 1 – Check zero; V 2 – Check weeded; V 3 – Imazethapyr 100 a.i. l -1 – 100 ml a.i. ha -1 ; 

V 4 – Imazamox 40 a.i.l -1 - 48 ml a.i. ha -1 ; V 5 - Imazamox 40 a.i.l -1 – 40 ml a.i. ha -1; V 6 - 

Imazamox 40 a.i. l -1 – 40 ml a.i. ha -1 - + DESH – 500 ml a.i. ha -1 ; V 7 - Imazamox 40 a.i. l -1 – 40 

ml a.i. ha -1 - + DESH – 1000 ml a.i. ha -1 ; V 8 - Bentazone 600 a.i. l -1 – 900 ml a.i. ha -1 – Fluazifop- 

P-butyl 150 a.i. l -1 – 225 ml a.i. ha -1 . 

The highest density was found for Setaria spp. and Echinochloa crus 

galli L. from the group of annual monocotyledonous weeds and for 

Amaranthus spp., Sinapis arvensis L. and Chenopodium album L. from the 

annual dicotyledonous ones representing 57% and 41%, respectively with 

regard to their weight per m 2 . From the group of the perennial weeds only 

Convolvulus arvensis L. was found with 1% participation. 

Due to the mixed type of weed infestation, herbicides having effect 

on the two weed groups were chosen in the study. The highest herbicidal 

97


efficacy reaching to 95% was explained by wide-spectrum action of 

Imazethapyr. The same efficacy was attained as a result of the mutually 

complementary effect of the herbicides Bentazone (anti-broadleaved) and 

Fluazifop-P-butyl (anti-grass) applied in a system. 

With regard to its spectrum of action, the herbicide Imazamox 

belongs to the group of wide-spectrum herbicides with contact effect. Our 

observations showed that Chenopodium album was susceptible only at the 

earliest stages of its development (from cotyledons to first leaf). When 

applied alone at doses of 48 ml a.i. ha -1 and 40 ml a.i. ha -1 , the herbicidal 

efficacy was 91% and 84%, respectively. Addition of the adjuvant DESH at 

a dose of 1000 ml/ha -1 to the herbicide at the lower dose resulted in an 

increase of the herbicidal efficacy by about 8% and reached to 92%. The 

adjuvants stimulate the herbicide uptake and as a result the herbicidal effect 

also increases, which in its turn provides a possibility for reduction of the 

herbicide doses (Dimitrova, 2007; Mathiassen and Kudsk, 2002; Kieloch and 

Domardzki, 2005). The positive effect of adjuvant application to some 

herbicides allows optimizing their doses, which has an favourable effect on 

environment. 

The studied herbicides showed selectivity to red clover. In the system 

of Bentazone-Fluazifop-P-butyl no signs of phytotoxicity were observed at 

all. In the first two weeks after treatment there was leaf chlorosis in a very 

slight to slight degree (score 2-3), which then was overcome and had no 

negative residual effect in the application of Imazethapyr, Imazamox and 

Imazamox + DESH. 

The removal of the competitive effect of weeds contributed to 

formation of a uniform dense sward with prevailing participation of the 

cultivated component (Table 2). 

Table 2. Participation of red clover in the sward (weight %) 

Variant * Red clover, % Weeds, % 

V 1 36 64 

V 2 100 0 

V 3 94 6 

V 4 91 9 

V 5 85 15 

V 6 88 12 

V 7 92 8 

V 8 94 6 

Variant*: as in Table 1 

In the zero check (V 1 ) red clover participated in the sward only with 

36% and the weeds prevailed in the herbaceous association with 64%. In the 

98

Chemical weed control in stands of red clover (Trifolium repens L.) in the year ... 

herbicide-treated stands (from V 3 до V 8 ) the crop participation varied from 

85 to 94% and the weeds were from 6 to 15%. 

The positive effect of the chemical weed control found expression in 

the harvested yield of dry biomass from the treated sward (Table 3). On 

average for the experimental period the yield from the zero check (V 1 ) was 

42% lower than that from the weeded check (V 2 ). The removal of the 

competitive effect of weeds by herbicide treatment increased the dry biomass 

yield by 44 tо 66%, as compared to that from the zero check and besides at 

very high statistical significance of the differences. 

Table 3. Yield of dry biomass of red clover (without weed participation) in 

the year of stand establishment, kg/ha -1 

Variant* 2006 2007 

Average for 

2006-2007 

%V 1 %V 2 

V 1 1680 1580 1630 100 58 

V 2 2930 2650 2790 171 100 

V 3 2840 2580 2710 166 97 

V 4 2670 2460 2570 158 92 

V 5 2460 2240 2350 144 84 

V 6 2550 2340 2450 150 88 

V 7 2700 2460 2580 158 92 

V 8 2720 2500 2610 160 94 

LSD P 5% 75.2 122.0 74.6 

P 1% 104.4 169.4 103.6 

P 0.1% 145.1 235.6 144.1 

Variant*: as in Table 1 

Conclusions 

The chemical weed control in the red clover stands in the year of their 

establishment was successful through application of the herbicides: 

Imazethapyr 100 a.i.l -1 – 100 ml a.i. ha -1 ; Imazamox 40 a.i.l -1 - 48 ml a.i. ha -1 ; 

Imazamox 40 a.i.l -1 – 40 ml a.i. ha -1 + DESH – 1000 ml ha -1 ; Bentazone 600 

a.i. l -1 – 900 ml a.i. ha -1 ; Fluazifop-P-butyl 150 a.i.l -1 – 225 ml a.i. ha -1 

applied at the two to four true leaf stage of the crop. 

The treatment with herbicides resulted in establishment of uniform 

stands with red clover participation of 85 to 94% in the sward and an 

increase of their dry biomass productivity by 44 to 66%. 

References 

BENKOV, B. and TS. DIMITROVA, 1983: Chemical weed control in stands of red clover 

for seed and forage. Plant Science, ХХ, 5, 24-29. 

COLUMA, 1973: Compte rendu des journees d ’ etudes sur les herbicides. France. 

99


DIMITROVA, TS., 2007: The problem of weeds in spring forage pea (Pisum sativum L.) for 

grain, Herbologia, vol. 8, №1, 29-34. 

KIELOCH, R. and K. DOMARADZKI, 2005: The influence of relative humidity on 

Anthemis arvensis and Stellaria media control by tribenuron – methyl used аlone 

and with adjuvants. 13-th EWRS Symposium, Bari, Italy, GD-ROM. 

KUDSK, P. and J.C. STREIBIG, 2003: Herbicides-a twoedged sward. Weed Research, vol. 

43. Number 2, 90-102. 

LYUBENOV, YA. et al., 1987: Integrated systems of weed control, volume 1, Zemizdat, 

Sofia. 

MATHIASSEN, S., P. KUDSK, 2002: The influence of adjuvants on the efficacy and 

rainfastness of indosulfuron. 12-th EWRS Symposium, 2002, Wageningen, 206- 

207. 

PRODANOV, I., 1980: Chemical control of weeds and red clover in lucerne stands for seed 

production. Plant Science, ХVII, 4, 148-156. 

RYBAK, H., 1976: Effects of several herbicides on red clever seed production. Canada. 

YANCHEVA, HR., 2007: Red and white clover, Agriculture plus, 1, 2-8. 

100


Instruction to Authors in 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, 

on the page (paper) format of B5, font of Times New Roman, font size 12 

(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 intruduction, 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. corn 

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 ).

herb. 9, 2 - anubih

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