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Bulawayo, Zimbabwe

Mupangwa W.,Matopos Research Station | Mupangwa W.,University of the Free State | Twomlow S.,IFAD Regional Office | Walker S.,University of the Free State
Journal of Arid Environments | Year: 2013

Declining soil productivity is one of the greatest challenges facing smallholder agriculture. This study assessed effects of reduced tillage and mulching on soil organic carbon, bulk density, infiltration and maize yield. Treatments consisted of three tillage methods (conventional ploughing, ripping and planting basins) combined factorially with mulch levels (0, 0.5, 1, 2, 4, 8 and 10 t ha-1). The experiment was run for four growing seasons allowing for a rotation of maize, cowpea and sorghum in some of the fields. A new experimental field was opened each year and maintained in subsequent seasons until the end of the experiment.Soil organic carbon increased with time in all tillage systems and more SOC gained in planting basins. Soil bulk density decreased with time in all tillage systems irrespective of mulch quantity applied. Ripping loosened the soil much deeper than the other tillage methods. Total infiltration in all treatments was similar over the four seasons. Soil structural changes resulted in increased unsaturated hydraulic conductivity and sorptivity of the clay loam soil. Maize yield increased with time in all treatments. Long term studies need to be conducted to substantiate the results on soil property and crop yield improvements observed in the reported study. © 2012 Elsevier Ltd.

Owen E.,University of Reading | Smith T.,Matopos Research Station | Makkar H.,Food and Agriculture Organisation of the United Nations
Animal Feed Science and Technology | Year: 2012

This paper summarises the major issues discussed by participants of a moderated e-conference hosted by the FAO Livestock Production Systems Branch of the Animal Production and Health Division from 01 September to 30 September 2010, entitled " Successes and failures with animal nutrition practices and technologies in developing countries" A total of 239 e-mail messages were posted by 120 scientist participants from 45 countries. A total of 15 technologies/practices were considered in a sequence based on calls from the Moderator and receipt of messages. The technologies/practices considered were: urea-ammonia treatment of straw, stall-grazing of crop residues/self-selection, reducing particle size of crop residues, enzyme treatment or solid state fermentation of crop residues, food-feed crop systems, urea as a supplement, urea-molasses-multinutrient feed block, mineral supplementation, fertilisers and mycotoxins, pasture improvement and reclamation, silvopastoral and agroforestry systems, forage production, forage conservation, forage fractionation, non-conventional feeds, organic farming. The current status of applying different animal nutrition technologies/practices is presented together with an analysis of the reasons for success or failure. Many messages discussed why technologies to increase the nutritive value of straws for feeding ruminants, especially urea-ammonia treatment, failed to be adopted by farmers. The major reasons, also relevant to many of the other technologies discussed, were weakness of extension services in developing countries, failure of scientists to involve farmers when developing new technologies and failure to demonstrate convincing benefit:cost ratios. The conference makes a contribution to knowledge concerning feeding ruminants and lessons learned for the future. © 2012.

Abdalla K.,University of KwaZulu - Natal | Abdalla K.,Desertification Research Institute | Chivenge P.,University of KwaZulu - Natal | Chivenge P.,Matopos Research Station | And 3 more authors.
Biogeosciences | Year: 2016

The management of agroecosystems plays a crucial role in the global carbon cycle with soil tillage leading to known organic carbon redistributions within soils and changes in soil CO2 emissions. Yet, discrepancies exist on the impact of tillage on soil CO2 emissions and on the main soil and environmental controls. A meta-analysis was conducted using 46 peer-reviewed publications totaling 174 paired observations comparing CO2 emissions over entire seasons or years from tilled and untilled soils across different climates, crop types and soil conditions with the objective of quantifying tillage impact on CO2 emissions and assessing the main controls. On average, tilled soils emitted 21% more CO2 than untilled soils, which corresponded to a significant difference at P<0.05. The difference increased to 29% in sandy soils from arid climates with low soil organic carbon content (SOCC<1%) and low soil moisture, but tillage had no impact on CO2 fluxes in clayey soils with high background SOCC (>3%). Finally, nitrogen fertilization and crop residue management had little effect on the CO2 responses of soils to no-tillage. These results suggest no-tillage is an effective mitigation measure of carbon dioxide losses from dry land soils. They emphasize the importance of including information on soil factors such as texture, aggregate stability and organic carbon content in global models of the carbon cycle. © Author(s) 2016.

Mupangwa W.,Matopos Research Station | Mupangwa W.,University of the Free State | Twomlow S.,IFAD Eastern and Southern Africa Regional Office | Walker S.,University of the Free State
International Journal of Agricultural Sustainability | Year: 2016

Soil water and nutrients are critical drivers of crop production for smallholders of southern Africa. A three-year study was conducted to assess the effect of integrating single and double ploughing, ripping and planting basins with nitrogen fertilizer (0, 10 and 20 kg N ha–1) on soil water dynamics and maize (Zea mays L.) yields. The experimental design was factorial with four tillage methods and three nitrogen levels as treatment factors. The study was conducted under semi-arid conditions of Zimbabwe. Tillage methods had similar soil water patterns in the profile and no tillage × N interaction effects were observed on soil water dynamics. Soil water penetrated deeper into the profile under ripper and basin methods than conventionally ploughed treatments. Nitrogen increased maize yields (14–96%) and rainwater-use efficiency (20–92%) regardless of tillage methods and growing season quality. However, more studies are required to explore complementary techniques that can improve rainwater capture and prolong soil water storage, and improve soil fertility. © 2015 Taylor & Francis.

Mpofu L.T.,ZSAES | Mpofu L.T.,Matopos Research Station | McLaren N.W.,Plant science Plantwetenskappe
Planta | Year: 2014

A lack of understanding of host-by-pathogen relations can hinder the success of breeding for resistance to a major disease. Fungal strain pathogenicity has to be understood from the virulence it can cause on susceptible genotypes and host resistance indicates which genotypes have resistance genes. Where the two worlds meet lies the place where researchers match the prevalent pathogen in the area of production with resistant varieties. This paper uses ergosterol concentration analysis as a measure of fungal biomass accumulation to assess levels of resistance in host genotypes. 11 sorghum genotypes were inoculated with 5 strains of fungi that are known to be associated with grain mold disease of sorghum. The resulting interaction was analyzed using GGE Biplot analysis and Cluster analysis which showed that none of the genotypes were resistant to Phoma sorghina and Curvularia lunata. Three genotypes were resistant to Fusarium thapsinum. One fungal strain (Alternaria alternata) does not contribute any significant damage in the grain mold disease. Fusarium graminearum causes very little grain mold disease. There was no correlation between the fungal strains. Visual scoring did not correlate with ergosterol accumulation. Resistance to grain mold in sorghum is shown to be due to vertical or specific resistance genes. Sorghum breeders should, therefore, identify predominant fungal strains in their localities and then locate and tag these resistance genes in their germplasm and pyramid them in commercial varieties. © 2014 The Author(s).

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