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

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The significant soybean yield could have been due to differences in management of the research fields where the trials were located. It appears the location used for the 1996/97 trial to test the rate effect of the two liming materials could have been managed so that soil fertility was improved and that influenced soybean yield. Conclusion and Recommendation The residual effect of NMT increased the soil pH and exchangeable magnesium of the study soil. However, the increase in soil pH and exchangeable magnesium did not increase soybean grain yield. It is recommended that a study of the residual effect be conducted for a longer time for NMT to completely react to conclusively evaluate its effectiveness for soybean production in acid soils of the high rainfall area of Zambia. Acknowledgement We acknowledge with many thanks the financial support from Zambia Consolidated Copper Mine (ZCCM), without that this work would not haVe been carried out. We thank the Government of the Republic of Zambia for logistical and administrative support given during the execution of this work. References Adams F., 1984. Crop response to liming in the southern United States. In: F. Adams (ed.) Soil Acidity and Liming. 2nd Ed. Agronomy 12:211-265. Day, P.R 1965. Particle fractionation and particle size analysis. In: c.A. Black et al., (Eds.) Methods of Soil Analysis. Part 1. Agronomy. American Society of Agronomy, Madison, WI, USA. De Oliveira E.L., and M.A. Pravan 1996. Control in soil acidity in no-tillage system for soybean production. Soil and Tillage Research 38:47-57. Goma H., Phiri S., and A. Mapiki 1990. Liming needs of some benchmark soil series of the high rainfall zone of Zambia. Soil Productivity Research Programme Annual Report. Misamfu Research Center, p.o. Box 410055, Kasama, Zambia. Gnmdon N.J. 1982. Acid soil amendments, soil chemistry and plant growth. Proceedings of the International Conference on Fertilizer Usage in the Tropics (Fertrop). Kuala Lumpur, Malaysia. Kamprath, E.J. 1967. Soil Acidity and response to Liming. International soil testing. North Carulina State Univ. Agric Exp. Station Tech. Bull. 4. Raleigh, NC, USA. SAS Institute, 1995. SAS User's Guide: Statistics. Version ed.> Statistical Analysis System Institute, Cary, New York, USA. Soil Taxonomy and Agrotechnological Transfer Report 1985. Proceedings of the X1 U ' International Forum on Soil Taxonomy and Agrotechnology Transfer. Zambia. Soil Survey Staff 1992. Keys to Soil Taxonomy. 5 th Edition. SMSS Technical Monograph No. 19. Pocahontas Press, Inc, Blacksburg, Virginia, USA. 556 pp. Steel RG.D., and J.H. Torrie 1980. Principles and Procedures of Statistics. McGraw-Hill Book Co. Inc., New York, USA. Mengel E.A., and K. Kirkby 1987. Liming and its calcium nutrition. 4 th Ed. International Potash Institute, Bern, Switzerland. MW1yinda K 1984. Relationship between pH (CaCh) and aluminium saturation. Proceedings of The Seminar on Soil Productivity in the High Rainfall Areas of Zambia, Lusaka, 8t11-10 th February 1983. 208 Grain legumes and Green Manures for Soil Fertility in Southern Afries
Questions and Answers Improving the Productivity of Grain Legumes and Green Manures To Obed I. Lungu and Kalaluka Munyinda Q: Was the reduction in yields after adding MAP not due to N2 fixation reduction by the presence of N in the MAP? A: No, all treatments received optimal N, and N2 fixation was not being evaluated in this study. PAPR has no N, but these treatments received N from either urea or ammonium nitrate. Q: 1) Were these trials conducted on station or on farm? 2) If on farm, do farmers still get the benefits of PAPR if they plant late or weed less effectively? 3) What is the cost of getting P20S per unit of nutrient by applying PAPR compared to DAP, considering the bulk of PAPR is inert material? A: 1) The trials were researcher-designed and farmer managed. They were both on farm and on station. 2) PAPR is just a substitute or alternative to MAP, TSP, etc. Farmers would therefore manage their crops with PAPR in the conventional way. 3) At only 10% P20S in PAPR, the material is bulky. The product that will be promoted will be beneficiated by a physical process to at least 15% P20S as already demonstrated. Additionally, the utilization of PAPR is being promoted for areas close to the deposits of PR. Q: Should RP work still be considered a priority given that so much work has been done, but these materials are most often not available nor sufficiency reactive? A: Yes, PR work is still needed, but there should be a shift from basic research on-station to promotion and demonstration on-farm. Soils are acutely deficient in P, and adequate P application is in excess of 80 kg P20S ha·1, which is beyond what small farmers can afford especially since imported fertilizers in the region cost at least four times their cost outside Africa. The local product would be developed and made available to farmers if there was the political will and the policy and institutional support. To Atusaye Mwalwanda, et al. Q: I do not think the effect of S increase was studied, when looking at your treatments? A: The fertilizer source used was unfortunately a Grain Legumes and Green Manures for Soil Fertility in Southern Africa compound fertilizer 23:21:0:4S, hence it is difficult to isolate the individual effects of nutrients. However, the response to the inorganic fertilizer is an indication of the deficiency of the elements in the soils at the study sites. Q: In your first conclusion your attribute an increase in yield to P and S, but what is the economic return for the extra yield versus the cost of nutrients? A: Economic analysis was not done in this study. There is need to do that analysis to get the benefit from using inorganic fertilizer compared with not using. To Lackson K Phiri, et al. Q: Ca and Mg are usually leached into the sub-soil. In your assessment of the residual effect of the liming materials tested on soil Ca and Mg levels, what was the justification for tracing the two bases down to 20 cm soil depth only? A: I agree that there is the possibility of Ca and Mg leaching in a high rainfall envirorunent such as where the trial was located. But the trial was only in the second year so our interestwas to see what was happening in the rooting depth (0 - 20 cm) and later assess the leaching of these cations down the soil profile. Unfortunately funding ended prematurely. Q: Your results do not mention the effect of increasing lime material on available phosphorous, but only mention pH and exchangeable AP+ effects. Why did you not mention P availability since it is very much influenced by AP+? A: Certainly P is critical. Indeed in the middle of the trial in the 1995/96 season, P deficiency symptoms were observed such that an additional 20 kg P20s/ha had to be added to correct P deficiency. General Discussion C: How much yield benefit after a fallow is necessary for the system to yield more than with two years of cropping? The naive answer is "twice as much". But maize next year is not worth as much as maize in your hand - an effect economists call "discounting". This means the yield improvement must be more than two times for the fallow to be viable. On the other hand, the fallow may take less labour and may benefit long term-fertility or reduce weed populations, which implies that less than 209
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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
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EFFECT OF DIFFERENT GREEN MANURE LE
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.. ~ 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
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 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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