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

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Among BNF systems, symbiotic systems involving legume/bacteria associations have the highest N2 fixing capability because N2-fixing microorganisms are supplied directly from the hos} plant with carbohydrates as a ready source of energy for N2 fixation. Therefore, root nodulation and N2 fixation are more complete and efficient when all the essential plant nutrient elements are available in sufficient quantities to the macrosymbiont. This fact is not always appreciated, and legumes are generally thought to be so well endowed that that they will fix N2 regardless of their non-N nutrition status. Phosphorus plays a critical regulatory function in photosynthesis and carbohydrate metabolism of leaves and P deficiency can limit growth, particularly during the reproductive stage of the crop. In the N2 fixation reaction involving the catalyzing enzyme complex nitrogenase, energy in the form of a r~d uctant Adenosine Tri-phosphate (A TP) is essential. Ciaquinta and Quebedeaux (1980) reported that the level of P supply during this period regulates the starch/sucrose ratio in the source leaves and the partitioning of photosynthates between the source leaves and the reproductive organs. This effect of P on partitioning of photosynthate is presumably responsible for the insufficient photosynthate supply to nodulated roots of phosphorusdeficient legumes and the occurrence of nitrogen deficiency symptoms in N2-fixing legumes receiving deficient levels of phosphorus (Marschner, 1986). Root infection with Versicula-Arbsucular (V A) mycorrhizae (Aguilar et al. 1979) not only increased P uptake from soil, but also VA aided the establishment of bacteria that fix N2 in soils that are low in available phosphorus. PR would be one way to provide the PR at low cost, but this mode of application was not effective with Zambian PR. In current field trials, simply processed partially acidulated PR (PAPR) was utilized. The main objective of this study was to evaluate the agronomic effectiveness of P APR produced from simply-processed phosphate rock products in soils of varying soil chemical properties, for grain legumes. Materials and Methods The field trials were conducted in two Agroecological Regions of varying rainfall, length of growing season and soil properties, as shown in Figure 1. In the first year (2000/1 cropping season), seven trials were conducted consisting of four On Station and thr,ee On-Farm experiments. Three On Station trials were planted in Agro-ecological Region II at Kafuku Farm Institute in Mukonchi, University Farm (UNZA) and Magoye Cotton Development Trust (COT) on Mushemi, Chelstone and Nakambala soil series respectively, One On-Station trial was planted in Region I at Lusitu. All the onfarm trials were planted in Region II at Chibwe on Mushemi soil series, Colden Valley Agricultural Research Trust (CART) on Makeni soil series and at Magoye Mwanachingwala village on Nakambala soil series. The sites were selected for their low available phosphorus fertility status. The initial soil test values for P and pH are shown in Table 1. All the soils were slightly acid, to acid, and deficient in plant available phosphorus. Therefore, crop response to applied phosphorus fertilizer was expected at all these sites. Phosphorus deficiency is a major factor limiting crop production in the tropics, presumably because of the fixation of phosphate by iron and aluminum oxides. Much more P fertilizer, therefore, is required to meet crop requirements over and above the quantities that are fixed. The cost of fertilizers is often the reason for inadequate fertilization. In the second cropping season (2001/2002), the tri Tentative Distribution olSoil Series in the PAPR Project Implementatfon Area of Zambia Many countries in Sub-Saharan Africa (--_._......_..... "\ are rich in phosphate rock (PR)-the ! LEGEND primary raw material for the produc -Sou Series tion of phosphate fertilizers. Because I -Maur,a of low local demand and the global """""'" I i 'A'~J surplus of P fertilizers, these deposits "':J~ I Mu~lill have not been developed. Technical, ()IhoQr 8on.~ economic and conducive policy re -La...... l~ ~ J gimes are needed to initiate tapping of Se.t, I: 5.010,0.0 ._.... 100&1 .....,__.... ,..., these resources and providing them at low cost. Direct application of ground Figure 1. Agro-ec%gica/ Regions of Zambia 190 Grain Legumes and Green Manures for Soil Fertility in Southern Africa
Table 1. Reduction of soil acidi.ty after liming at experimental sites. Acidity (cmol kgl) lime added Site A1 3 • + H" A1 3 • kg hal Initial After liming 1. Chibwe 0.20 0.10 360 5.1 5.3 2. GART 1.00 0.66 1500 4.1 5.2 3. Magoye COT 0.30 0.24 510 4.1 4.5 4. Mwanachingwala 0.34 0.28 450 4.4 5.1 5. lusitu 0.12 0.10 450 4.3 5.4 als were extended to three other sites - one site in Eastern Province (Region II) and two in Northern Province (Region III). Phosphorus was applied as mono-ammonium phosphate (MAP) as the reference fertilizer and as partially acidulated phosphate rock (PAPR) produced at the Pilot Plant of the School of Mines at the University of Zambia from Chilembwe phosphaterbck. The trials were designed as On-Farm, or On-Station in which the plots were 100 m2 and 22.5 m2 respectively. The P application rates were 0, 60 and 120 kg P20S ha· J in On-Farm trials and 0, 40, 80, 120, 160 and 200 kg P20 S ha- 1 in On-Station trials. All treatments were replicated fouT times in a randomized complete block design. The fertilizer was banded in the planting furrow below the seed at planting. All treatments received adequate amounts of K, S as recommended for the particular sites (70 kg and 26.4 kg ha- 1 respectively). Nitrogen was applied as a basal application at 24 kg N ha- 1 at On-Farm sites and 44 kg N ha- 1 at On-Stati0n sites. The test crops were maize; sorghum, sunflower and legumes (soybean, groundnut and cowpea). A peat-based inoculum was applied to soybean at planting using the recommended rate. The test crops were grown for . two seasons, and in all cases improved varieties of test grain legumes were planted according to the suitability and importance of the legume in the locality of the trial. In Onstation trials in Region II, soybean variety Kaleya and groundnut variety MGV4 were planted. These varieties are well adapted to Region II and are very responsive to inoculation with Rhizobium. The MGV 4 groundnut variety is tolerant to soil acidity and has low pod failure (Pops) in these soils. Soybean was grQwn at Kafuku Farm Institute and UNZA Farm, groundnut at Magoye CDT. Cowpea variety Bubebe was grown at Lusitu in Region 1. The variety was grown because of its earliness and high yields, the former attribute being particularly important in this drought prone Region. Soybean was drilled at an inter row spacing of 75 cm. Groundnut was grown at an inter- and intrarow spacing of 75 cm and 10 cm respectively. The spacing for cowpea was 75 cm between rows and 10 em between plants. pH During the second cropping season (2001/2002), ~he planting furrows from the first season were maintained. However, the crops were rotated around the plots at each sit~ . No further applications of P were made to the higher rates of P application (120, 160 and 200 kg P20S ha- I ), and the residual effects were evaluated from these treatments. Other nutrients, N, P, K and S including the application of inoculum were repeated as in the first season according to the current fertilization practice. An absolute control treatment in which no fertilizer was applied was included for sites where space permitteQ. adjacent to the current trial. The treatments were split, and a lime treatment was included to evaluate its effect on crop growth, especially on the acid soils at Chibwe, GART, Magoye (both on-station and on-farm) and Lusitu sites. Each original treatment plot was split into two equal subplots, and one half was limed while the other was not limed. The amount of lime applied was calculated based on the exchangeable aluminium values (Table 1). The lime was broadcast on the surface and then worked into the soil by light cultivation using hand hoes before planting. Crop growth was monitored during the season, and some plant growth parameters were recorded. Crop management both in the first and second cropping seasons was carried out according to the conventional agronomic practices for these crops. Results and Discussion Although various test crops were evaluated, only the results for the grctin legumes are presented and discussed in this paper. These results are discussed according to crop across trial sites. Soybean At Kafuku Farm Institute (sited on Mushemi soil series), a response to soybean biomass and grain yield was obtained in the second cropping season only with the application of PAPR at 40 kg P20S ha- 1 . There was a tendency for the residual effect of both MAP and PAPR to decrease with increasing P level, reaching a minimum when P was applied at 160 kg P20S ha- 1 and subsequently increasing at the highest rate of P application. This is illustrated in Figure 2, showing the effect of source and level of P on soybean grain yield. The soils at Chibwe On-Farm sit-e · were similar to those at Kafuku Farm Institute except that the soils were higher in initial soil P. Consequently in the first cropping season (2001/02), there was no yield Grain Legumes and Green Manures for Soil Fertility in Southern Africa 191
Page 2 and 3:
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
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 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)
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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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