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

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o ') holding capacity of the soil. This directly causes an increase in crop vigour and grain yields. The objective of this project was to e\'aluate the biomass production of sunnhemp and velvet bean and the grain production of cowpea and soyabean on two acid soils of Northern Zambia. The work was designed to specifically: • Determine the influence of soil characteristics on legume establishment, growth and biomass production, • Assess the contribution of grain legumes and green manures to soil fertility. Materials and methods This experiment was conducted for two agricultural seasons: 2001/2002 and 2002/2003. The worked reported in this paper is for the 2001/2002 season. The experiment was conducted on the Misamfu soil series at Misamfu Regional Research Centre (10 0 10' S, 31 0 12' E) on an Ultisol and at Mungwi District (10 0 10' S 31 0 15' E) on an Aliisol. A composite soil sample was collected at 0-20 cm soil depth from each site of the trial. The soil sample was dried and ground to pass through a 2 mm sieve. The following properties were analyzed: pH (in 0.01 M CaCh), Al saturation, exchangeable acidity, P (Bray 1) total nitrogen (Kjeldahl), organic carbon (Walkley and Black, 1934), exchangeable cations (1.0 M ammonium acetate, pH 7.0). Particle size was also determined using the Pipette method. Table 1 shows the soil chemical data. Sunnhemp, velvet bean, cowpea and soyabean sole crop treatments were planted. Velvet bean was planted to give a plant population density of 44000 plants ha·1, sunnhemp was drilled at a seeding rate of about 20 kg ha·1, while cowpea and soyabean were also drilled at about 80 kg seed ha·l . The plot sizes were 5 x 5 m. The design was an RCBD replicated three times. The above ground biomass of sunnhemp was determined at the flowering stage and then ploughed un- Table 1. Initial chemical soil properties of a composite sample (0·20 cm depth) of the experimental sites in northern Zambia Soil characteristics Misamfu Mungwi pH (in 0.01 M CaCh) 4.5 4.7 Organic carbon ('¥o) 0.60 1.31 Bray 1 P (mg kg') 1.07 2.65 Exch. K(cmoltkg') 0.47 0.97 Exch. Ca (cmoltkg') 0.28 0.84 Exch. Mg (cmoltkg') 0.03 0.08 AI saturation ('¥o) 20 10 der while cowpea and soya bean grain were harvested at maturity along with the above ground biomass production for green manures and grain production for the grain legumes. Results and Discussion Both soils are acidic but the Mungwi soil is slightly more fertile than the Misamfu soil, as seen from the available P and pH (Table 1). Green manures established well at both sites. Soyabean established well on both soil types but cowpea establishment was bad on the two sites because it was attacked by pests. Above-ground biomass produced by the two green manures was similar on both soil types (Table 2). Mungwi site produced a higher grain yieid of soyabean than the Misamfu site while cowpea yield was poor throughout (Table 3). The green manures tested on these acidic soils in northern Zambia seem to have the potential to produce adequate biomass to allow a cereal crop to produce sufficient grain yield. Breman and Reuler (2002) reported a cowpea above-ground biomass of 2800 kg ha·l . On the acid soils of Northern Zambia, from 2000 to 2767 kg ha- 1 sunnhemp above-ground biomass was produced (Table 2). The total content of N accumulated by legume green manures during N2-fixation has been measured by various authors. Up to 250 kg N ha- 1 yr- 1 was reported to accumulate in green legumes (Giller and Wilson, 1991; Peoples and Herridge, 1990). Assuming an average 3% N concentration, then from our experiments,sunnhemp was able to produce about 59 kg N ha- 1 on the Mungwi soil and 83 kg ha- 1 N on the Misamfu soil, while velvet bean produced 63 and 60 kg N ha- 1 respectively on these two soil types. Since commercial fertilizers are expensive, a smallholder farmer would be able to produce enough maize grain yield to meet food security by planting the green manure, because they would be able to supplement part of the N fertilizer requirement of 120 kg N ha- 1 recommended for maize in Zambia (McPhillips, 1987). The grain yield of cowpea was very low on the Misamfu soil due to low fertility. However, soyabean performed much better on that same soil. Cowpea was also diseased and this was largely responsible for the low grain yield obtained. On the Table 2. Means of green Table 3. Means of grain legume manure above ground biomass grain yields (kg ha in Zambia (kg hal) in Zambia Treatments Misamfu Mungwi Treatment Misamfu Mungwi Cowpea 9.2 83.3 Sunnhemp 2767 1967 Soyabean 792 1313 Velvet bean 2000 2100 CV ('¥o) 115.8 36 CV (%) 46.09 13.17 Probability 0.18 0.03 186 Grain legumes and Green Manures for Soil Fertility in Southern Africa
Mungwi soil, cowpea and soyabean produced a higher grain yield compared to the Misamfu site. This again follows the fertility trend of the two soil types as shown in Table 1. Cowpea production was well short of potential. The potential rainfed production of cowpea has been reported to be 1200 kg ha'\ of cowpea grain, in addition to the 2800 kg ha- 1 of folder or green manure, in the Sudanian savannah (Breman and Reuler, 2002). However, on the acid soils of Northern Zambia, less than 100 kg ha- 1 was produced (Table 3) . This could be due to high Al saturation common in these soils (Table I), which might affect root-rhizobium symbiosis involved in N2 fixation, as well as to low available P leading to the low grain yield. According to Breman and Reuler (2002), legumes will flourish under conditions of poor N but available P. The acid soils of Northern Zambia are low in both N and in available P (this is due to P fixation by these acid soils). Soyabean grain yield was relatively higher on the more fertile Mungwi soil than the more acid soil (Table 3). In the less acidic soils of southern Zambia, average grain yield of 2000 kg ha'\ with rhizobium applications have been recorded (McPhillips, 1987). Thus even under acid soils, reasonable yield of soyabean grain can be achieved as long as seed is inoculated prior to planting. Conclusion Despite the soils being acidic, establishment of green manures and soyabean was good. Mungwi soil, being slightly fertile than Misamfu soil, produced a higher soyabean grain yield. Cowpea grain yield on both sites was low, not because of the acid soil, but due to pest infestation which is a major problem in the cultivation of cowpea in Northern Zambia. The benefit due to the green manures will be assessed in the next season. References Bowen, T. 1997. The 1995/96. Fertilizer verification trial. Econ9mic analysis of results for policy discussion. Malawi Ministry of Agriculture and Livestock Development, Lilongwe, Malawi. 22 pp. Bowen, W.T., Quintana, J.O., Pert'ira, J., Bouldin, D. R., Reid, W.5. and Latwell. D.T. 1988. Screening legume green manures as nitrogen sources to succeeding non-legume crops. Plant and Soil 111:75-80. Breman, H and Reuler van, H. 2002. Legumes: When and Where an Option? In: Vanlauwe, B., Grain legumes and Green Manures for Soil Fertility in Southern Africa Diels, J., Sanginga, Nand Merckx, (eds). -Integrated Plant Nutr.ient Management in sub-Saharan Africa. CABI International, Wallingford, UK. Gilbert, R.A. i 988. Understanding green manures for soil fertility enhancement in the maize-based cropping systems of Malawi. In: Waddington, S. R., Murwira, H.K., I
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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
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Table 1. Non-legume cropping patter
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Table 9. Common pests on cowpeas as
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few of the farmers interviewed acqu
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Murwira, H.K., M.J. Swift and P.G.H
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Materials and Methods On farm exper
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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
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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 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: PERFORMANCE OF GREEN MANURES AND GR
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
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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
Page 233 and 234: Table 1. Gross margins from the dif
Page 235 and 236: Abstract LINKING TECHNOLOGY DEVELOP
Page 237 and 238: 3. If households are linked to prod
Page 239 and 240: Table 9. Average Table 8. Pigeonpea
Page 241 and 242: ance of sorghum-pigeonpea intercrop
Page 243: 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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