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

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and how best to invest a given bundle of resources among several alternatives while minimizing the risk of their portfolios. Conceptual Framework and Hypotheses For farmers to invest resources in new technologies such as organic and inorganic fertilizers, the rates of return on these investments need to be competitive with returns on available alternative investment opportunities. Within a single crop enterprise such as maize production, the return on investment in new fertilizer technologies is compared with the return on capital using traditional soil-mining methods. Between different crop enterprises, returns on investment in new management technologies are compared against other investments including livestock, off-farm activities, temporary and permant labor migration. Because of the uncertainty of payoffs to alternative investments, new investments must fit farmers' objectives and requirements for risk in addition to profitability. Because high returns are associated with high risks, farmers face trade-offs between allocating resources to activities with high profits and more desirable but riskier and therefore less attractive outcomes compared to activities with low profits and yet less riskier, which makes them more appealing. Moss, Weldon, and Featherstone (1991) have developed an approach for evaluating risk-return tradeoffs and diversification opportunities of alternative farm investments that is based on the portfolio theory of financial markets and the capital asset pricing model (CAPM). These analysts argue that for a new or candidate enterprise to improve the risk-return tradeoff provided by any existing group or portfolio of enterprises, the following condition must hold If the mean return divided by the standard deviation of new investment alternative is greater than the mean of the whole farm plan's return divided by the standard deviation times the correlation between investments the new investment will complement the current operation from a risk-return perspective. Based on this risk-return condition necessary for a new enterprise to improve the risk-return trade-off provided by the current farm's portfolio, one can calculate a risk diversification index (RDI) as follows: r r RDI _i _.-L n r'ip a: I a: I If the RDI is greater than zero, the candidate technology is a good investment opportunity for diversification. But if RDI is less than zero the candidate technology offers no gains through diversification to the farm household. Applying this conceptual framework generates the following two hypotheses about relationships between the ~'isk-return characteristics of new technologies, farmers' risk management strategies, and potential for adoption that are tested in the study: l. Legume-based soil fertility management technologies are attractive if they lie on the riskefficient frontier and offer farmers expected returns that are high enough to compensate them for additional risks; and 2. Diversification into legume-based soil fertility management technologies will benefit farmers if the new technologies complement the current farm portfolio and better offset the total risk of the whole farm compared to allocating resources to alternative farm and non-farm investment opportunities available to farmers. Where O'i = the meim return of the potential new investment alterna tive, = the standard deviation of the new alternative, = the mean return of the current whole farm r" plan, CY p = the standard deviation of the current whole farm plan, and = the correlation between the current whole farm plan's return and the new enterprise's return. Methods The study uses enterprise and whole-farm budgeting, and simtllation modeling with APSIM and @RISK to evaluate the hypotheses. Enterprise budgets are constructed for alternative investment technologies. Different enterprises are defined by different outputs such as maize, sorghum, chickens, goats and cattle; sole stands and crop mixtures; and different crop prod uction technologies, including low and high rates of application of kraal manure, pit-treated manure, inorganic Nitrogen fertilizer and organic and inorganic fertilizer combinations. Enterprise budgets are used to compare the profitability of maize and sorghum crop production using traditional methods and improved soil fertility 80 Grain legumes and Green Manures for Soil Fertility in Southern Africa
management technologies with different activities aggregating the returns per unit over the number of available to farmers and the profitability of different units produced by 'the households. Because there ~nterprises for households with different resource are expenses and 'revenues that cannot be allocated endowments. The budgets are constructed using to particular enterprises, and cases where we do.not yield and input-output coefficients data from farm have a linear budget this may under~stimate resurveys, Farmer Participatory Research experi turns to some activities. The budgets are used to esments, and yields predicted by the Agric:dtural Pro timate the expected annual returns, the degree of duction Systems Simulator (APSIM) model. 'D'e risk, and correlation coefficients for different crop input-output coefficients are combined with prices and livestock combinations. from the Ministry of Agriculture, Zimbabwe Farmerst Union and Commercial Farmers' Union to calculate gross margins per hectare for crops and per breeding animal unit for livestock. Input prices are Results and Discussion reported at the supply point. Input prices paid by Tables I, 2, and 3 present the annual returns and farmers are estimated by adding input prices re risks per hectare above fixed costs for 11 years from ported by suppliers and the cost of transport. Out 1990/91 to 2000/01 on alternative maize and sorput prices are reported at the marketing point. ghum soil fertility production technologies by farm Farm gate prices are estimated conservatively by household typology. The tables also include the andeducting cost of transportation from prices at mar nual return and risk of investing funds in a risk-free keting points. The opportunity cost of family labor asset, the POSB savings account. For male-headed is estimated by multiplying the minimum wage rate households with resident husband and higher labor of engaging in urban employment multiplied by the and draft animal resource-endowments, the most probability of finding a job. profitable production technologies are, indecreasing order of importance, maize plus 9 kilograms of Because APSIM crop yield predictions are only ritrogen per hectare, maize plus kraal manure plus available for 10 year,s from 1990 to 2000 and for a 18 kilograms of nitrogen per hectare, maizefew improved technology options this analysis focuses on sole maize and sorghum Table 1. Expected annual returns (Zimbabwe $/ha) and risk of alternative maize and sorghum grown without fertilizer and with soil fertility management technologies for male·headed households, Gwanda, Tsholotsho and small quantities of Nitrogen fertilizer; kraal and pit manure; manure Zimuto, 1990/91,2000/01 Gwanda Tsholo'tsho Zirnuto and, Nitrogen fertilizer combinations; sole cowpeas and groundnuts; Activity Return Risk Return Risk Return Risk maize and sorghum-cowpea and groimdnut intercrops and rotations, maize-cowpea and maizegroundnut rotations. The budgets include only the physical grain output of crop enterprises for primary and secondary crops valued at pose savings account Sorghum+kraal manure Sorghum +Okraal manure +ON Maize+Okraal manure+ON Sorgirum+9N Maize +groundnut intercrop Sorghum+groundnut intercrop 289 ·15272 -2440 3286 -849 1738 -3486 328 3948 4350 4526 5856 6302 6403 289 ·13793 ·156 5046 1911 1260 ·43,83 328 5310 6347 5759 7642 8213 8872 289 4249 ·2285 328 7688 5969 farm gate prices. Farmers frequently produce crops in mixtures of more than two crops and the budget needs to include the whole mixture. The values of byproducts such as stalks, which have value as livestock feed, in construction and composts are not included. Livestock budgets include the market value of the animal, depreciation on the value of breeding animals, milk, eggs, and draught power. Values of animal manure and tradi 'tiona I religious ceremonies are not included. The enterprise budgets are used to construct whole farm budgets for current farm plans for different household categories by Sorghum +pit manure -1888 6752 542 8752 Sorghum·groundnut rotation 554 7033 2914 8054 Sorghum+cowpea rotation ·319 7422 8769 11024 Maize+9N 4286 7450 7188 7160 6860 7913 Maize groundnut rotation 3888 7535 6800 8902 5764 7862 Maize +cowpea rotation 3412 7545 12743 10542 8591 10656 Sorghum +18N -2330 7703 788 9718 Sorghum+ ~raal +18N ·154 7759 3314 10160 Maize +kraal manure +9N 2629 8296 6547 7984 6127 8498 Maize+pit manure 2414 8723 6417 7768 6281 9q2 Maize+ cowpea intercrop -1179 9006 6875 10783 168 9807 Maize +kraal manure 3717 9220 5557 9774 4303 9785 Sorghum +cowpea intercrop ·5177 9306 3498 13359 Sorghum +kraal manure +9N -450 9765 2711 11107 Maize+ 18N 1614 9804 5588 8436 6081 10255 Maize +kraal manure +18N 3894 10286 8293 8874 8951 10480 Grain Legumes and Green Manures for Soil Fertility in Southern Africa 81
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
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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 42 and 43: Historical Perspective on Soyabean
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: RISK DIVERSIFICATION OPPORTUNITIES
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
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18000 1600) 14000 a) Zambia 12000 m
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EFFECT OF DIFFERENT GREEN MANURE LE
Page 145 and 146:
.. ~ Table 2. The effect of time o
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Chivinge, O.A., E. Kasembe, and I.K
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times with regionally specific adap
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ter content at 180 cm was still wel
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to amount of biomass, quality of bi
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with the natural fallow, which did
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and K to maize as an equivalent amo
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forts to understand the mechanisms
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gen recovery rates in relation to p
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The first steps to improve soil fer
Page 167 and 168:
Questions and Answers .Identificat
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MUCUNA - MAIZE ROTATIONS AND SHORT
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Table 3. Percent nitrogen (% N) con
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~e decomposition of legume residues
Page 176 and 177:
Table 3. Effect of forage legumes o
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available nutrients and vice versa,
Page 180 and 181:
Conclusion and Recommendation Mucun
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Specific objectives were to: • Te
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'"~ v '" ~ ~ 1400000 1200000 100000
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EFFECT OF SURFACE APPLICATION AND I
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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
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3500 .f"'3000 ca ,c2500 CI "" - 200
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above-ground biomass was not transl
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3000 "0 ]i >. ,5 ~ C> 800 600 400 2
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Most interventions involving green
Page 208 and 209:
~ ~~----.-~r-~-------------r~~ Aoo
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stover N, followed by after pigeon
Page 212 and 213:
tems in Malawi and Zimbabwe. Procee
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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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