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

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Historical Perspective on Soyabean in Zimbabwe Soyabean was introduced into Zimbabwe (then Southern Rhodesia) in the 1930s as a green manure crop and later for forage. Large-scale commercial production started in the 1960s when a breeding program and a Rhizobium inoculant factory were established (Corby, 1967). The crop was not promoted among smallholder black farmers, most of whom had been relocated onto marginal, often sandy, soils in low rainfall areas unsuitable for soyabean production. Apart from the real agro~ ecological limitations, soyabean production, with its requirement for rhizobium inoculants that need refrigeration, was considered too sophisticated for African peasant farmers who had no knowledge on how to process it for food. After political independence in 1980, government adopted a policy of encouraging smallholder farmers to increase crop production through various inputs and marketing support programs. By the 1990s, smallholder farmers were contributing over 70% of national maize and cotton production. A soyabean BNF promotion program targeted at Hurungwe West district in northern Zimbabwe in the late 1980s boosted farmer interest, production and consumption of soyabean which all declined when project support ended in 1989 (Whingwiri, 1996; Mudimu, 1998). Smallholder farm communities however continued to face limited dietary protein sources, general declining soil fertility and poor household incomes against a background of increasing mineral N fertilizer prices, following World Bank/IMF-induced removal of government subsidies. A two-day stakeholders' workshop that was held at the University of Zimbabwe in February 1996 to examine the potential for promiscuous soyabean for smallholder farmers recommended two major activities. First it resolved that research be initiated to characterize indigenous soyabean rhizobia, the potential for promiscuous soyabean and to quantify the amounts of N fixed and the residual fertility benefits for maize grown in rotation. Secondly, it was resolved to extend soyabean technologies (the use of rhizobial inoculants and promiscuous varieties for BNF, production, processing, utilization and later input/output marketing) to smallholder farmers. A National Soyabean Promotion Task Force with representation from farmer organizations, private industry, NGOs and public institutions (research, extension, university) was formed. The Task Force was to be convened by AGRlTEX with overall coordination by the University of Zimbabwe Faculty of Agriculture. The Task Force objectives included promotion of soyabean through appropriate research, training farmers in production and processing and coordinating the activities of various stakeholders. This paper outlines the conceptual framework and mechanisms used to promote soyabean technologies, the scale of operations, feedback from farmers, constraints and opportunities and the potential for scaling up. Conceptual Framework The context was that of smallholder cropping systems characterized by low productivity due to low soil fertility, with N as a major limiting nutrient. Biological N fixation (BNF) was identified as a potential tool to address N deficiency in these systems. Soyabean was chosen as the candidate legume because of its high N-fixing potential and soil improving properties, food value as a protein and vegetable oil source, relatively low production costs and high market value. The place of soyabean BNF in the total food production system of a typical smallholder farm was identified. This was an essential step to ensure that the technology would address real food security concerns of farmers, a critical element for successful adoption. The conceptual framework illustrated below (Figure 1) shows the main linkage loops and benefits from soyabean BNF in an integrated maize-based crop-livestock system. Strategies Translating the Concept into an Operational Model For research, a proposal was written up, funds sourced and graduate students engaged to conduct research to quantify N inputs from promiscuous and commercially inoculated soyabean into the cropping system and to measUre and demonstrate the residual soil fertility benefits for maize in subsequent seasons. Research was conducted to establish the prevalence and symbiotic effectiveness of indigenous rhizobia on both promiscuous and specific soyabean varieties and the adaptability of the latter to the more agro-ecologically marginal smallholder areas. Experiments were conducted both on-station and on-farm under researcher and farmer-extension ~ L:'::':~::d~ So,_be,," BNF~ s,,;. F",~';" ~
management respectively. This meant that researcher-managed detailed replicated field experiments were placed on a few farms selected for their representative soil types, while a larger number of simple plus/minus treatment trials were run under farmer management with extension officers monitoring them. Rhizobial inoculation, liming and basal compound fertilizers and promiscuous versus specific nodulating soyabean varieties were tested. Both farmers and extension personnel helped to set up and monitor experiments and gained valuable experience and confidence in managing a soya bean crop. Scientific data obtained was used to strengthen the extension messages that had hitherto been extrapolated from work done in large-scale commercial production under somewhat different agro-climatic conditions. For the promotion aspect, the main strategies were: training of both farmers and extension staff on how t9 apply rhizobial inoculants, how to grow, weed and harvest soya bean; facilitating access to inputs, setting up technology transfer demonstrations that involved farmers and extension staff, regular follow-ups and communication in local languages at all times. Train-the- trainer workshops targeted extension staff in AGRITEX, NGO personnel and farmer leaders identified by their organizations and employed a hands-on practical approach. Topics included how to store and apply rhizobial inoculants, use of promiscuous varieties where inoculants are unavailable, how to check if nodules are effective, identification of pests and diseases and their control. Training was consolidated by a vigorous pr
Page 2 and 3: Grain Legumes and Green Manures for
Page 4 and 5: 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
Page 14 and 15: 100 90 80 - - 0 - - Uptake by ihe m
Page 16 and 17: - 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
Page 39: Questions and Answers ~ey Papers To
Page 44 and 45: ganic amendment for resource-poor f
Page 46 and 47: MPhil. Thesis. University of Zimbab
Page 48 and 49: deal of research work has been bias
Page 50 and 51: 1600 '7 ns 1400 ~ 1200 Cl ~ 1000 "C
Page 52 and 53: Arbuscular mycorrhizal fungi (AMF)
Page 54 and 55: 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.
Page 60 and 61: Series no 5. Soil Science SOciety o
Page 62 and 63: Materials and Methods Persistence o
Page 64 and 65: content resulted in increased rhizo
Page 66 and 67: (Mugwiia and Murwira, 1997). Howeve
Page 68 and 69: Table 2. Average maize yield estima
Page 70 and 71: implied that most fanners prefer to
Page 73 and 74: ] Questions and Answers Rhizobium,
Page 75 and 76: ADDING A NEW DIMENSION TO THE IMPRO
Page 77 and 78: Materials and Methods The study use
Page 79 and 80: a) Chikwaka b) Chinyika !21 C. absu
Page 81 and 82: Table 3. N, P and Kconcentrations (
Page 83 and 84: Abstract SCREENING OF SHORT DURATIO
Page 85 and 86: Table 2. Characteristics of short d
Page 87 and 88: RISK DIVERSIFICATION OPPORTUNITIES
Page 89 and 90: management technologies with differ
Page 91 and 92: Table 3. Expected annual returns (Z
Page 93:
Table 6. Risk diversification indic
Page 96 and 97:
een renewed interest in green manur
Page 98 and 99:
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
Page 105 and 106:
7000 6000 ';' €.. 5000 .~MzSole :
Page 107 and 108:
Table 5. Maize grain yield (kg ha")
Page 109:
Phiri, A.D.K. 1999. Effects of Sesb
Page 112 and 113:
amount of roots with sl:nnhemp. It
Page 114 and 115:
It was proved that a mixed farming
Page 116 and 117:
Table 3. Above·ground biomass (t/h
Page 118 and 119:
and horticulture in Zimbabwe: Case
Page 121 and 122:
GRAIN LEGUMES AND GREEN MANURES IN
Page 123 and 124:
Results Table 1. Adaptation of gree
Page 125 and 126:
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 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 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
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
Page 246 and 247:
To Charles Nhemachena, et al. Q: 1)
Page 248 and 249:
• 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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