ICRISAT Bulawayo

Bulawayo, Zimbabwe

ICRISAT Bulawayo

Bulawayo, Zimbabwe
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Rusinamhodzi L.,CIAT TSBF Harare | Rusinamhodzi L.,Wageningen University | Corbeels M.,CIRAD Annual Cropping Systems | Zingore S.,International Plant Nutrition Institute Africa | And 2 more authors.
Field Crops Research | Year: 2013

Soil fertility decline is a major constraint to crop productivity on smallholder farms in Africa. The objective of this study was to evaluate the long-term (up to nine years) impacts of nutrient management strategies and their local feasibility on crop productivity, soil fertility status and rainfall infiltration on two contrasting soil types and different prior management regimes in Murehwa, Zimbabwe. The nutrient management strategies employed in the study were: a control with no fertiliser, amendments of 100kg Nha-1, 100kg N+lime, three rates of manure application (5, 15 and 25tha-1) in combination with 100kg Nha-1, and three rates of P fertiliser (10, 30 and 50kg Pha-1) in combination with 100kg N, 20kg Ca, 5kg Zn and 10kg Mnha-1. Maize grain yields in sandy soils did not respond to the sole application of 100kg Nha-1; manure application had immediate and incremental benefits on crop yields on the sandy soils. A combination of 25tha-1 manure and 100kg N gave the largest treatment yield of 9.3tha-1 on the homefield clay soils, 6.1tha-1 in the clay outfield, 7.6tha-1 in the homefield and 3.4tha-1 in the eighth season. Yields of the largest manure application on the sandy outfields were comparable to yields with 100kg N in combination with 30kg P, 20kg Ca, 5kg Zn and 10kg Mnha-1 in the homefields suggesting the need to target nutrients differently to different fields. Manure application improved rainfall infiltration in the clay soils from 21 to 31mmh-1 but on the sandy soils the manure effect on infiltration was not significant. Despite the large manure applications, crop productivity and SOC build-up in the outfield sandy soils was small highlighting the difficulty to recover the fertility of degraded soils. The major cause of poor crop productivity on the degraded sandy soils despite the large additions of manure could not be ascertained. The current practice of allocating manure and fertiliser to fields closest to homesteads exacerbates land degradation in the sandy outfields and increases soil fertility gradients but results in the most harvest for the farm. On clay soils, manure may be targeted to outfields and mineral fertiliser to homefields to increase total crop productivity. Farmers who owned cattle in the study site can achieve high manure application rates on small plots, and manure application can be rotated according to crop sequences. Consistent application of manure in combination with mineral fertilisers can be an effective option to improve crop yield, SOC and moisture conservation under smallholder farming conditions. Combined manure and mineral fertiliser application can be adapted locally as a feasible entry point for ecological intensification in mixed crop-livestock systems. © 2013 Elsevier B.V.

Rusinamhodzi L.,CIAT TSBF Harare | Rusinamhodzi L.,Wageningen University | Corbeels M.,CIRAD Annual Cropping Systems | Van Wijk M.T.,Wageningen University | And 3 more authors.
Agronomy for Sustainable Development | Year: 2011

Conservation agriculture involves reduced tillage, permanent soil cover and crop rotations to enhance soil fertility and to supply food from a dwindling land resource. Recently, conservation agriculture has been promoted in Southern Africa, mainly for maize-based farming systems. However, maize yields under rain-fed conditions are often variable. There is therefore a need to identify factors that influence crop yield under conservation agriculture and rain-fed conditions. Here, we studied maize grain yield data from experiments lasting 5 years and more under rain-fed conditions. We assessed the effect of long-term tillage and residue retention on maize grain yield under contrasting soil textures, nitrogen input and climate. Yield variability was measured by stability analysis. Our results show an increase in maize yield over time with conservation agriculture practices that include rotation and high input use in low rainfall areas. But we observed no difference in system stability under those conditions. We observed a strong relationship between maize grain yield and annual rainfall. Our meta-analysis gave the following findings: (1) 92% of the data show that mulch cover in high rainfall areas leads to lower yields due to waterlogging; (2) 85% of data show that soil texture is important in the temporal development of conservation agriculture effects, improved yields are likely on well-drained soils; (3) 73% of the data show that conservation agriculture practices require high inputs especially N for improved yield; (4) 63% of data show that increased yields are obtained with rotation but calculations often do not include the variations in rainfall within and between seasons; (5) 56% of the data show that reduced tillage with no mulch cover leads to lower yields in semi-arid areas; and (6) when adequate fertiliser is available, rainfall is the most important determinant of yield in southern Africa. It is clear from our results that conservation agriculture needs to be targeted and adapted to specific biophysical conditions for improved impact. © INRA and Springer Science+Business Media B.V. 2011.

Rusinamhodzi L.,CIAT TSBF Harare | Rusinamhodzi L.,Wageningen University | Corbeels M.,CIRAD Annual Cropping Systems C O Embrapa Cerrados | Nyamangara J.,ICRISAT Bulawayo | Giller K.E.,Wageningen University
Field Crops Research | Year: 2012

Many farmers in central Mozambique intercrop maize with grain legumes as a means to improve food security and income. The objective of this study was to understand the farming system, and to evaluate the suitability of maize-legume intercropping to alleviate the biophysical and socio-economic constraints faced by smallholder farmers in Ruaca and Vunduzi villages, central Mozambique. To achieve this we characterised the farming systems and measured grain yields, rainfall infiltration, economic returns and acceptability of maize-legume intercrops under different N and P application rates. Two intercropping strategies were tested: (a) an additive design of within-row intercropping in which legume was intercropped with alternating hills of maize within the same row; maize plant population was the same as sole crop maize, and (b) a substitutive design with distinct alternating rows of maize and legume (local practice). Fertiliser treatments imposed on all treatments were: (i) no fertiliser, (ii) 20kgPha-1, (iii) 20kgPha-1+30kgNha-1, and (iv) 20kgPha-1+60kgNha-1. Intercrops were relatively more productive than the corresponding sole crops; land equivalent ratios (LER) for within-row intercropping ranged between 1.1 and 2.4, and between 1.0 and 1.9 for distinct-row intercropping. Average maize yield penalty for intercropping maize and pigeonpea in the within-row was small (8%) compared with 50% in the distinct-row design; average (season×fertiliser) sole maize yield was 3.2tha-1. Intercropping maize and cowpea in within-row led to maize yield loss of only 6%, whereas distinct-row intercropping reduced maize yield by 25% from 2.1tha-1 of sole maize (season×fertiliser). Cowpea yield was less affected by intercropping: sole cowpea had an average yield of 0.9tha-1, distinct-row intercropping (0.8tha-1) and the within-row intercropping yielded 0.9tha-1. Legumes were comparatively less affected by the long dry spells which were prevalent during the study period. Response to N and P fertiliser was weak due to poor rainfall distribution. In the third season, maize in rotation with pigeonpea and without N fertiliser application yielded 5.6tha-1, eight times more than continuous maize which was severely infested by striga (Striga asiatica) and yielded only 0.7tha-1. Rainfall infiltration increased from 6mmh-1 to 22mmh-1 with long-term maize-legume intercropping due to a combination of good quality biomass production which provided mulch combined with no tillage. Intercropping maize and pigeonpea was profitable with a rate of return of at least 343% over sole maize cropping. Farmers preferred the within-row maize-legume intercropping with an acceptability score of 84% because of good yields for both maize and legume. Intercropping increased the labour required for weeding by 36% compared with the sole crops. Farmers in Ruaca faced labour constraints due to extensification thus maize-pigeonpea intercropping may improve productivity and help reduce the area cultivated. In Vunduzi, land limitation was a major problem and intensification through legumes is amongst the few feasible options to increase both production and productivity. The late maturity of pigeonpea means that free-grazing of cattle has to be delayed, which allows farmers to retain crop residues in the fields as mulch if they choose to; this allows the use of no-tillage practises. We conclude that maize-legume intercropping has potential to: (a) reduce the risk of crop failure, (b) improve productivity and income, and (c) increase food security in vulnerable production systems, and is a feasible entry point to ecological intensification. © 2012 Elsevier B.V.

Nkomboni D.,Matopos Research Institute | Sisito G.,Matopos Research Institute | van Rooyen A.,ICRISAT Bulawayo | Homann-Kee Tui S.,ICRISAT Bulawayo | And 2 more authors.
Livestock Research for Rural Development | Year: 2014

Despite the importance and opportunities that cattle present to smallholder farmers, their productivity remains low. High mortality and low fertility mainly caused by feed and health related factors are the reasons of low cattle productivity in semi-arid Zimbabwe. Mortality is unproductive as cattle that die, die with the feed that they eat. As most of the rain water is used for feed production through transpiration, mortality wastes it and lowers livestock water productivity (LWP). In this study we characterize the existing situation of feed, health, herd size and assess the impact of mortality and fertility on cattle production in semi-arid western Zimbabwe. The data were collected using household surveys and participatory rural appraisals (PRAs). Farmers were categorized into poor and better-off cattle keepers'wealth groups. A simulation approach using the DynMod model was applied to evaluate the extent livestock production and LWP can be improved by reducing mortality and increasing fertility of cattle from the wealth groups. Mortality was relatively high amongst the different classes of stock with an overall mortality rate of 0.17. Fertility was low with parturition rate of 0.48 on average. The projection of the current system showed a decline in cattle numbers for the poor and better-off farmers. For better-off farmers' cattle, mortality rate in absolute terms was higher than the poor farmers' cattle. Complex management with larger herds could be the reason for this trend. Reducing the mortality while increasing parturition rates improved cattle production for both poor cattle farmers and better-off cattle farmers despite the introduction of droughts after every 5years.We observed that as feed consumption increases with cattle numbers, the LWP index also increases. This results in effective utilization of feed resources. Addressing livestock management needs to be intensified as it was noted as an area of concern to address mortality and fertility challenges. Most farmers (64%) graze their crop residues in situ reducing fodder utilization. None of the farmers grow improved legumes and cereal forages for animal feeding during the dry season. Whereas, it was evident that feed shortages did not directly result in mortality except during prolonged drought when their immunity is compromised. Improving the extension services and better access to information, inputs and technologies on cattle production could have a strong impact on improving cattle productivity.

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