Grain Legumes and Green Manures for Soil Fertility in ... - cimmyt

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available nutrients and vice versa, and this leads to improved crop production and less movement of nutrients into the environment. The OM reduces evaporation losses and hence improves N use efficiency, and provides nutrients other than N. ]Jnder field conditions the fluctuations in sDil water content affect the release of N from green manure. A quantification of this effect is essential for predicting the supply of mineral N at a particular time (Brar and Sidhu, 1995). There is a progressive decline in mineral N· produc tion within the soil wi th decrease in soil water level (Brar and Sidhu, 1995). In a crop rotation (intercropping or relay) that includes growing green manure plants, ~he cereal crop and the green manure plants are likely to com 'pete for nutrients and moisture during the alternate season (McGuire et aL, 1998). Green manure crops planted during the fallow period may use the moisture needed for seed germination at planting, however this disadvantage is counter-balanced by other benefits of growing green manure during the fallow period. This study sought to evaluate the performance of est biomass followed by C. juncea (Table 2). The Crotalaria grahamiana, Crotalaria juncea, Mucuna prubiomasriens, Vigna unguiculata (Cowpea IT18) and Glycine affected by dry spells that came after crop establish production of Mucuna pruriens was more max (Magoye) legumes, and the effects of time of ment, while C. grahamiana produced higher biomass incorporation of residues on maize yields in in similar conditions. Murewa (high rainfall area) and Shurugwi (low rainfall). Materials and Methods The trial was conducted in two consecutive seasons (2000/01 and 2001/02). Green manure and grain legumes were grown in the first season followed by the maize in the second season. The experiment comprised of six treatments; three green manure crops (Crotalaria grahamiana, Crotalaria juncea and Mucuna pruriens), and two gra)n legumes (Vigna unguiculata (Cowpea) and Glycine max (Soya bean) and a control treatment with maize. The plots were split into two subplots for the analysis of the influence of time of incorporation of the residues at flowering and at the onset of the following season. For the maize control the plot was divided into two, one was bare (nothing grown in the subplot) and the other one had maize crops. Soil samples were taken when the plant materiai had been ploughed in the soil for the early incorporation subplots, while plants were still standing in the other subplots. Plant materials for biomass production measurements were taken before residue incorporation in each subplot. Soil samples for moisture content analysis were taken in each plot from 0-10, 10-20, 20-30 and 30-40 cm depths. They were dried and the moisture content determined. The resul ts were statistically analyzed using SAS software. Results and Discussion Biomass production Green and grain legumes were grown in the 2000/01 season for biomass production, and the crop residues were incorporated into the soil at dif ferent times for a subsequent maize crop in 2001/02. Biomass production was higher in Murewa (high rainfall, @ 900 mm) than in Shurugwi (low rainfall, @450 mm)) in the 2001/02 season. In Murewa, Mucuna pruriens produced the highest biomass followed by Crotalaria grahamiana, with cowpea producing the least biomass (Table 1). The N content of the residues was also determined. Adding all the' Mucuna pruriens residues harvested was equivalent to the addition of 156 kg N per ha. In Shurugwi, C. grahamiana outyielded Mucuna pr?lriens, with Crotalaria grahamiana producing the high Soil moisture content and maize yields In the second season (2001/2002) of the study, mois ture content was determined just before planting of maize, and maize yields were determined at har vest. An analysis of variance of moisture content measurements showed that soil depth had a signifi cant effect on moisture content. The interaction be- Table 1 .. Legume biomass yields production for 2000/01 season in Murewa Treatment Biomass yield {kg/hal Total N{kg/hal Cowpea 1442 4B.0 C. grahamiana 4535 137.0 Mucuna pruriens 4746 155.6 C. juncea 4120 llB.5 Soybeans 2300 77.7 LSD 1242.3 34.31 Table 2. Legume biomass yields production for 2000/01 season in Shurugwi Treatment Biomass yield {kg/hal Total N(kg/hal Cowpea lOBO 39.4 C. grahamiana 7507 24B.3 Mucuna pruriens 4932 121.4 C. juncea 5129 144.1 Maize 2120 (grain) LSD 1290.2 62.4 170 Grain legumes and Green Manures for Soil Fertility in Southern Africa
tween factors tested in the study did not show any significant effect for moisture content (Table 3). The mean separations by LSDo.os (least significant differ~ ence) of depth (LSDoos = 0.4975) showed that there was more moisture at 30-40 cm soil depth than other depths (Figure 1). The effect of time of incorporation on moisture content approached significance (0.0677). The comparison of means using LSDo.os (0.35) shows as well that there is no significant difference in moisture content between late (4.20%) and early (3.87%) incorporation of green manure residues. Statistically, the difference between times of incorporation of crop residues was significant at 10%. The timp. of soil sampling might have influenced the difference between treatments on moisture conservation. Samples were taken when the soil was too dry because of early cessation of rain and late onset of rains for the following season. However, the numerical difference shows that late incorporation of green manure conserved more moisture. This might be because in early incorporation the soil is exposed to the sun, and this increases evaporation, while in late incorporation the plants continue to cover the soil, -Nhich reduces evaporation. Table 3. ANOVA table of moisture content measurements Source OF Type III SS Mean Square FVal Pr > F Treatment 5 2.01 0.40 0.36 0.8772 Depth 3 60.34 0.11 17.78 < 0.0001 Time 3.86 3.86 3.42 0.0677 Treatment" Depth 15 16.00 1.07 0.94 0.5204 Treatment "Time 5 3.16 0.63 0.56 0.7309 Depth"Time 3 3.04 1.01 0.90 0.4460 Treatment 15 8.42 0.56 0.50 0.9372 "Depth"Time Residual 94 106.22 1.13 Total 143 210.74 There was a significant difference wi.thin treatments between late and early incorporation of crop residues (Figure 2) . . Late incorporation of cowpea, C. juncea, C. grahamiana and maize conserved more moisture than early incorporation, while incorporation time of mucuna and soyabean residues did ~ot show any significant ~ffect on moisture conservation. A trend of means (not statistically significal'1t) of the different treatments shows that soya bean had the least moisture content, followed by C. grahamiana, C. juncea, cowpea, maize and the highest to conserve moisture was Mucuna pruriens (Figure 3). This might be due to how these plants cover the ground. Mucuna pruriens provides a good cover because of its bushy habit that in return reduces evaporation from the ground. Addition of organic residues improves crop production through moisture conservation and nutrient supply to crops. Incorporated organic residues augment the water retention capacity of the soil by improving the structure and physical environment of soil. The maximum benefits are achieved by good timing of incorporation for growth of the' subsequent crop. Consequently, there is need to conserve soil moisture to avert moisture deficits at the time of sowing, and provide much-needed nutrients at early stages of plant growth. 4 '~------------~========~ _ Early(a ll\owa nng) _ L
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Grain Legumes and Green Manures for
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Acknowledgments • The Leopard Roc
Page 6 and 7:
Evall!ating mucuna green manure tec
Page 9:
INTRODUCTION AND CONFERENCE OBJECTI
Page 12 and 13:
Table 1. Paradigm shifts underlying
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100 90 80 - - 0 - - Uptake by ihe m
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- 6 ~ 9 8 7 0- 5 CḎ ns 4 0::: 3
Page 18 and 19:
Table 3. Millet grain and total dry
Page 20 and 21:
Dvorak KA 1996. Adoption potential
Page 23 and 24:
LEGUMES FOR SOIL FERTILITY IN SOUTH
Page 25 and 26:
to the system in such a way that th
Page 27:
Muetzelfeldt, R.1. 1995. A framewor
Page 30 and 31:
ing capacity. Legumes offer other b
Page 32 and 33:
people/km2), land holdings are smal
Page 34 and 35:
ments. It would help researchers to
Page 36 and 37:
Own livestock Gununo farmers for th
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Questions and Answers ~ey Papers To
Page 42 and 43:
Historical Perspective on Soyabean
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ganic amendment for resource-poor f
Page 46 and 47:
MPhil. Thesis. University of Zimbab
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deal of research work has been bias
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1600 '7 ns 1400 ~ 1200 Cl ~ 1000 "C
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Arbuscular mycorrhizal fungi (AMF)
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Boswell EP, Koide RT, Shumway DL, A
Page 56 and 57:
Materials and Methods The trial was
Page 58 and 59:
0.9 0.8 ~ 0.7 Rec '-' 0.6 Vl ::9 0.
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Series no 5. Soil Science SOciety o
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Materials and Methods Persistence o
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content resulted in increased rhizo
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(Mugwiia and Murwira, 1997). Howeve
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Table 2. Average maize yield estima
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implied that most fanners prefer to
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] Questions and Answers Rhizobium,
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ADDING A NEW DIMENSION TO THE IMPRO
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Materials and Methods The study use
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a) Chikwaka b) Chinyika !21 C. absu
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Table 3. N, P and Kconcentrations (
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Abstract SCREENING OF SHORT DURATIO
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Table 2. Characteristics of short d
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RISK DIVERSIFICATION OPPORTUNITIES
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management technologies with differ
Page 91 and 92:
Table 3. Expected annual returns (Z
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Table 6. Risk diversification indic
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een renewed interest in green manur
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unfertilised maize crop of over 200
Page 101 and 102:
Questions and Answers Screening of
Page 103 and 104:
GREEN MANURE AND FOOD LEGUMES RESEA
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7000 6000 ';' €.. 5000 .~MzSole :
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Table 5. Maize grain yield (kg ha")
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Phiri, A.D.K. 1999. Effects of Sesb
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amount of roots with sl:nnhemp. It
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It was proved that a mixed farming
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Table 3. Above·ground biomass (t/h
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and horticulture in Zimbabwe: Case
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GRAIN LEGUMES AND GREEN MANURES IN
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Results Table 1. Adaptation of gree
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Four rates of fertilizer N were app
Page 127 and 128: THE ROLE OF COWPEA (VIGNA UNGUICULA
Page 129 and 130: Table 1. Non-legume cropping patter
Page 131 and 132: Table 9. Common pests on cowpeas as
Page 133 and 134: few of the farmers interviewed acqu
Page 135: Murwira, H.K., M.J. Swift and P.G.H
Page 138 and 139: Materials and Methods On farm exper
Page 140 and 141: 18000 1600) 14000 a) Zambia 12000 m
Page 143 and 144: EFFECT OF DIFFERENT GREEN MANURE LE
Page 145 and 146: .. ~ Table 2. The effect of time o
Page 147: Chivinge, O.A., E. Kasembe, and I.K
Page 150 and 151: times with regionally specific adap
Page 152 and 153: ter content at 180 cm was still wel
Page 154 and 155: to amount of biomass, quality of bi
Page 156 and 157: with the natural fallow, which did
Page 158 and 159: and K to maize as an equivalent amo
Page 160 and 161: forts to understand the mechanisms
Page 162 and 163: gen recovery rates in relation to p
Page 164 and 165: The first steps to improve soil fer
Page 167 and 168: Questions and Answers .Identificat
Page 169 and 170: MUCUNA - MAIZE ROTATIONS AND SHORT
Page 171: Table 3. Percent nitrogen (% N) con
Page 174 and 175: ~e decomposition of legume residues
Page 176 and 177: Table 3. Effect of forage legumes o
Page 180 and 181: Conclusion and Recommendation Mucun
Page 182 and 183: Specific objectives were to: • Te
Page 184 and 185: '"~ v '" ~ ~ 1400000 1200000 100000
Page 187 and 188: EFFECT OF SURFACE APPLICATION AND I
Page 189: it 4 a···· · ... - :.!! e.....
Page 193 and 194: PERFORMANCE OF GREEN MANURES AND GR
Page 195: Mungwi soil, cowpea and soyabean pr
Page 198 and 199: Among BNF systems, symbiotic system
Page 200 and 201: 3500 .f"'3000 ca ,c2500 CI "" - 200
Page 202 and 203: above-ground biomass was not transl
Page 204 and 205: 3000 "0 ]i >. ,5 ~ C> 800 600 400 2
Page 206 and 207: Most interventions involving green
Page 208 and 209: ~ ~~----.-~r-~-------------r~~ Aoo
Page 210 and 211: stover N, followed by after pigeon
Page 212 and 213: tems in Malawi and Zimbabwe. Procee
Page 214 and 215: 1965). The tailings and AgLi were a
Page 216 and 217: The significant soybean yield could
Page 218 and 219: twice the yield is necessary. We ha
Page 220 and 221: Table 1. Maize and Grain Legumes Pr
Page 222 and 223: Recommendations and Conclusion In v
Page 224 and 225: performance of private sector compa
Page 226 and 227: the investment costs incurred. The
Page 228 and 229:
Results and Planning Workshop. Soil
Page 231 and 232:
A SOCIO-ECONOMIC ANALYSIS OF LEGUME
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Table 1. Gross margins from the dif
Page 235 and 236:
Abstract LINKING TECHNOLOGY DEVELOP
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3. If households are linked to prod
Page 239 and 240:
Table 9. Average Table 8. Pigeonpea
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ance of sorghum-pigeonpea intercrop
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Mligo, J.K., 1995. Pigeonpea breedi
Page 246 and 247:
To Charles Nhemachena, et al. Q: 1)
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• Assessment of the potential ben
Page 250 and 251:
few studies characterized the house
Page 252 and 253:
• Conduct more research to measur
Page 254:
Socio-Economics, Policy and Technol
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