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

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Conclusion and Recommendation Mucuna pruriens and Crotalaria grahamiana are potential best bets for soil fertility amelioration in communal areas of Zimbabwe. High biomass production was achieved for the two crops in the areas of study. Mucuna pruriens was more susceptible to dry spells that occurred in the middle of the growing season than C. grahamiana, but both crops need adequate moisture at planting for good establishment. Higher maize yields were obtained in plots where Mucuna and Crotalaria grahamiana residues were incorporated compared to other legumes. Time of incorporation had an effect on yield of the subsequent crop; maize yields in early-incorporated plots were higher than in late incorporated plots for all legumes. Incorporation of Mucuna residues conserved more moisture than other legumes, and moisture content was higher (but not significantly so) in late incorporated plots. This was probably due to the removal of plant cover in early incorporation, and hence high evaporation rates before the rains that depleted moisture in the soil. . Acknowledgements The authors greatly acknowledge IFAD for the funding of the research, as well as farmers in Murewa and Shurugwi for their collaboration in the trials. References Biederbeck, V.O. and O.T. Bouman, 1994. Water use by annual green manure legumes in dryland cropping systems. Agronomy Journal 86:543-549. Bolton, F.E. 1981. Optimising the use of water and nitrogen through soil and crop management. Plant and Soil 58:231-247. Brar, D.S. and A.S. Sidhu 1995. Effect of soil water on pattern of nitrogen release during decomposition of added green mantire residue. Journal of Indian Society of Soil Science 43:14-17. Buresh, R.J., T.T. Chua, E.G. Castillo, S.P. Liboon and D.P. Garrity 1993. Fallow and Sesbania effects on soil nitrogen dynamics in lowland ricebased cropping systems. Agronomy Journal 85:316-321. . Elliot, L.F and 'R.J. Papendick 1986. Crop residue management for improved soil productivity. Biology, Agriculture and Horticulture 3:131-142. Fugita, K, B. Ofusu and S. Ogata 1992. Biological nitrogen fixation in mixed legume-cereal cropping systems. Plant and Soil 141:155-175. Giller, KE. and KJ. Wilson 1991. Nitrogen fixation in tropical cropping systems. CAB International, Wallingford, UK 313 p. McGuire, A.M., D.C. Bryant and R.F. Denison 1998. Wheat yields, nitrogen uptake, and moisture following winter legume cover crop vs. fallow. Agronomy Journal 90:404-410. Peoples, M.B. and D.F. Herridge 1990. Nitrogen fixation by legumes in tropical ~d subtropical agriculture. Advances in Agronomy 44:155-223. Young, A. 1989. Agroforestry for soil conservation. CAB International, Wallingford, UK, 276 p. 172 Grain legumes and Green Manures for ~oil Fertility in Southern Africa
SOIL FERTILITY IMPROVEMENT THROUGH THE USE OF GREEN MANURE IN CENTRAL ZAMBIA MOSES MWALE', CASSIM MASI 2 , J. KABONG0 2 and L. K. PHIRI' 1Mt. Makulu Central Research Station, PIB 7, Chilanga, genetics@zamnet.zm, 2World Vision International, P. O. Box 31083, Lusaka, Zambia Abstract Farmers identify low soil fertility as a major problem affecting crop production in Chibombo, Central Province, Zambia. This means fertilizer is a prerequisite to crop production, particularly maize. But the use of fertilizer is not often viable due to its high cost and poor availability. To boost crop production, there was need to test alternative cost-effective soil fertility improvement techniques. An experiment was therefore conducted to reduce the soil fertility problem using green manures. Sunnhemp (Crotalaria juncea) and Velvet beans (Mucuna pruriens) were grown either as sole crops or intercropped with maize (in the 1998/99 season). Continuous maize (fertilized and unfertilized) and a natural grass fallow were used as controls. Only phosphorus (50 kg PzOs ha·1) was applied to the unfertilized (zero nitrogen) maize while compound 0 (10:20:10:8 : N P K S) at 100 kg ha·1 was applied to the other maize treatments. No fertilizers were added to the green manure treatments. All maize plots (except unfertilized maize) were top dressed with urea at a rate of 23 kg N ha- 1 . The dry matter yield of sunnhemp and velvet bean were determined just before flowering and all the above ground biomass was ploughed under. The maize was harvested at physiological maturity and grain weight determined. In the 1999/2000 season, maize was planted in all plots and cultural practices were the same as for 1998/99. Unfertilized maize had the lowest dry matter and grain yield (less than 1 t ha- 1 ) followed by maize after the grass fallow. All fertilized and green manure treatments yielded significantly more grain than unfertilized maize. There were no significant differences (p=0.05) between the maize grown after the green manures and that which. received fertilizer. Incorporating sunnhemp biomass not only increased the yield of maize but also increased the organic matter content of the soil at the experimental sites. Key words: Green manure, sunnhemp, velvet bean, profitability, sustainability, Zambia Introduction Low soil fertility is a major problem affecting crop production in Chibombo District of Zambia's Central Province. This has been made worse by farmers who commonly monocrop with maize year after year. This makes fertilizer use a prerequisite to crop production, particularly maize. The current prices of fertilizers are beyond the reach of most farmers in the area due to liberalization of the economy and the removal of fertilizer subsidies. The few that can afford fertilizers have reduced their application rates to far below those recommended, resulting in low crop yield!> per unit area cropped . . This has affected both food availability and income for many people. To boo~t crop production, there is a need to test alternative cost-effective soil fertility improvement techniques. An option identified by the farmers through participatory rural appraisal (PRA) was the 'lse of green manures notably sunnhemp (Crotalaria juncea), velvet bean (Mucuna pruriens) and some agroforestry tree prunings such as Sesbania sesban. These practices were part of the farming systems before mineral fertilizers and most elderly farmers still recall and appreciate the usefulness of the two green manure species. Crotalaria and Mucuna have shown to be excellent N2-fixers in a wide range of enVironments (Bowen, et al. 1988; Kolar et al. 1993; MacColl, 1990; Yost et al. 1985). Green manures have the potential to accumulate up to 250 kg N ha- 1 yr-l (Giller and Wilson, 1991) resulting in cereal grain yield increases of 600 - 4100 kg ha- 1 (Peoples and Herridge, 1990). The use of a green manure may also boost the levels of soil organic matter resulting in improved soil structure, better root proliferation and soil water holding capacity. This would in tum increase crop vigour and yields. There is a need therefore to evaluate the beneficial effects of these green manures on farmers' fields in Muswishi Agricultural Camp in Chibombo District and document the results. Project Objectives The overall objective was to address the soil fertility problem using green manures. Grain Legumes and Green Manures for Soil Fertility in Southern Africa 173
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Grain Legumes and Green Manures for
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Acknowledgments • The Leopard Roc
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Evall!ating mucuna green manure tec
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INTRODUCTION AND CONFERENCE OBJECTI
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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
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Table 3. Millet grain and total dry
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Dvorak KA 1996. Adoption potential
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LEGUMES FOR SOIL FERTILITY IN SOUTH
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to the system in such a way that th
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Muetzelfeldt, R.1. 1995. A framewor
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ing capacity. Legumes offer other b
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people/km2), land holdings are smal
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ments. It would help researchers to
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Own livestock Gununo farmers for th
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Questions and Answers ~ey Papers To
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Historical Perspective on Soyabean
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ganic amendment for resource-poor f
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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
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Materials and Methods The trial was
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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
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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
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Questions and Answers Screening of
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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
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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 178 and 179: available nutrients and vice versa,
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
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A SOCIO-ECONOMIC ANALYSIS OF LEGUME
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Table 1. Gross margins from the dif
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Abstract LINKING TECHNOLOGY DEVELOP
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3. If households are linked to prod
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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
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To Charles Nhemachena, et al. Q: 1)
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• Assessment of the potential ben
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few studies characterized the house
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• Conduct more research to measur
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Socio-Economics, Policy and Technol
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