Bulawayo, Zimbabwe
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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.


Love D.,WaterNet | Love D.,Matopos Research Station | Uhlenbrook S.,UNESCO IHE | Uhlenbrook S.,Technical University of Delft | And 3 more authors.
Water SA | Year: 2010

Changing regional and global trends in climate and discharge, such as global warming-related declines in annual rainfall in south-eastern Africa, are likely to have a strong influence on water resource availability, and to increase livelihood risk. It is therefore important to characterise such trends. Information can be obtained by examining and comparing the rainfall and runoff records at different locations within a basin. In this study, trends in various parameters of temperature (4 stations), rainfall (10 stations) and discharge (16 stations) from the northern part of the Limpopo Basin, Zimbabwe, were statistically analysed, using the Spearman rank test, the Mann-Kendall test and the Pettitt test. It was determined that rainfall and discharge in the study area have undergone a notable decline since 1980, both in terms of total annual water resources (declines in annual rainfall, annual unit runoff) and in terms of the temporal availability of water (declines in number of rainy days, increases in dry spells, increases in days without flow). Annual rainfall is negatively correlated to an index of the El Niño - Southern Oscillation phenomenon. The main areas of rising risk are an increasing number of dry spells, which is likely to decrease crop yields, and an increasing probability of annual discharge below the long-term average, which could limit blue-water availability. As rainfall continues to decline, it is likely that a multiplier effect will be felt on discharge. Increasing food shortages are a likely consequence of the impact of this declining water resource availability on rain-fed and irrigated agriculture. Declining water resource availability will also further stress urban water supplies, notably those of Zimbabwe's second-largest city of Bulawayo, which depends to a large extent from these water resources and already experiences chronic water shortages.


Love D.,WaterNet | Love D.,Matopos Research Station | Uhlenbrook S.,UNESCO IHE | Uhlenbrook S.,Technical University of Delft | And 4 more authors.
Hydrological Sciences Journal | Year: 2010

Characterizing the response of a catchment to rainfall, in terms of the production of runoff vs the interception, transpiration and evaporation of water, is the first important step in understanding water resource availability in a catchment. This is particularly important in small semi-arid catchments, where a few intense rainfall events may generate much of the season's runoff. The ephemeral Zhulube catchment (30 km2) in the northern Limpopo basin was instrumented and modelled in order to elucidate the dominant hydrological processes. Discharge events were disconnected, with short recession curves, probably caused by the shallow soils in the Tshazi sub-catchment, which dry out rapidly, and the presence of a dambo in the Gobalidanke sub-catchment. Two different flow event types were observed, with the larger floods showing longer recessions being associated with higher (antecedent) precipitation. The differences could be related to: (a) intensity of rainfall, or (b) different soil conditions. Interception is an important process in the water balance of the catchment, accounting for an estimated 32% of rainfall in the 2007/08 season, but as much as 56% in the drier 2006/07 season. An extended version of the HBV model was developed (designated HBVx), introducing an interception storage and with all routines run in semi-distributed mode. After extensive manual calibration, the HBVx simulation satisfactorily showed the disconnected nature of the flows. The generally low Nash-Sutcliffe coefficients can be explained by the model failing to simulate the two different observed flow types differently. The importance of incorporating interception into rainfall-runoff is demonstrated by the substantial improvement in objective function values obtained. This exceeds the gains made by changing from lumped to semi-distributed mode, supported by 1 000 000 Monte Carlo simulations. There was also an important improvement in the daily volume error. The best simulation, supported by field observations in the Gobalidanke sub-catchment, suggested that discharge was driven mainly by flow from saturation overland flow. Hortonian overland flow, as interpreted from field observations in the Tshazi subcatchment, was not simulated so well. A limitation of the model is its inability to address temporal variability in soil characteristics and more complex runoff generation processes. The model suggests episodic groundwater recharge with annual recharge of 100 mm year-1, which is similar to that reported by other studies in Zimbabwe. © 2010 IAHS Press.


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.


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 | Walker S.,University of the Free State | Twomlow S.,Matopos Research Station
Journal of Arid Environments | Year: 2011

Smallholder agriculture in semi-arid Zimbabwe is dependent on the seasonal characteristics of rainfall. The determination of start, end and length of the growing season, and the pattern of dry spells during the season is useful information for planning land preparation and planting activities. This study was designed to assess whether there has been any changes in the start, end and length of growing season and the pattern of 14 and 21 day dry spells during the season. Daily rainfall data were collected from five meteorological stations located in southern Zimbabwe. Results indicated that no significant changes in the start, end and subsequent length of growing season occurred over the past 50-74 years. There was no significant change in the number of wet days per season over the period reviewed. There is a high probability of 14 and 21 day dry spells during the peak rainfall months. The relationship between start and end of growing season is stronger as aridity increases. We conclude that growing seasons have not changed significantly over the past 50-74 years in southern Zimbabwe. As smallholder agriculture continues to be affected by dry spells and droughts, there is scope in exploring rainwater management technologies in rainfed cropping systems. © 2011 Elsevier Ltd.


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.


Mupangwa W.,Matopos Research Station | Mupangwa W.,University of the Free State | Twomlow S.,Matopos Research Station | Walker S.,University of the Free State
Field Crops Research | Year: 2012

Proponents of conservation agriculture (CA) argue that the CA approach offers the greatest opportunity to increase the productivity in smallholder agro-ecosystems. This study was designed to assess (1) first year maize, cowpea and sorghum yield responses to a combination of reduced tillage and mulching and (2) maize yield responses to rotation with cowpea and sorghum in reduced tillage systems. Two conservation tillage methods (ripping and planting basins) combined factorially with seven mulch levels (0, 0.5, 1, 2, 4, 8 and 10tha -1) were compared with conventional mouldboard ploughing. The experiment was run for four consecutive growing seasons allowing for a rotation of maize, cowpea, sorghum and maize in some fields used in the study. Crop yields were determined across all tillage and mulch combinations in each year. Tillage system had no significant effect on maize yield while maize grain yield increased with increase in mulch cover in seasons that had below average rainfall. Mulching at 2-4tha -1 gave optimum yields in seasons with below average rainfall. Tillage system and mulching had no significant effect on cowpea yield when soil moisture was not limiting. However, the ripper and basin systems had 142 and 102% more cowpea grain than the conventional system in 2006/2007 because of differences in planting dates used in three systems and poor rainfall distribution. The conventional and ripper systems gave 26 and 38% more sorghum grain than the basin system. Rotating maize with cowpea and sorghum resulted in 114, 123 and 9% more grain than first year maize, maize-maize monocrop and maize-cowpea-maize in the conventional system. In the ripper system, maize-cowpea-sorghum-maize rotation gave 98, 153 and 39% more grain than first year maize, maize-maize monocrop and maize-cowpea-maize rotation. In the basin system, maize-cowpea-sorghum-maize rotation gave 274, 240 and 43% more grain than first year maize, maize-maize monocrop and maize-cowpea-maize rotation. However, long term studies under different soil, climatic and socio-economic conditions still need to be conducted to substantiate the observations made in the reported study. © 2012 Elsevier B.V.


Mupangwa W.,Matopos Research Station | Mupangwa W.,University of the Free State | Twomlow S.,Matopos Research Station | Walker S.,University of the Free State
Physics and Chemistry of the Earth | Year: 2012

The persistent droughts, dry spells, and chronic food insecurity in semi-arid areas necessitate the introduction of more robust rainwater harvesting and soil water management technologies. The study reported here was conducted to assess the influence of dead level contours and infiltration pits on in-field soil water dynamics over two growing seasons. A transect consisting of six access tubes, spaced at 5. m interval, was established across each dead level contour with or without an infiltration pit before the onset of the rains. Two access tubes were installed upslope of the contour while four tubes were installed on the downslope side. Dead level contours with infiltration pits captured more rainwater than dead level contours only resulting in more lateral soil water movement. Significant lateral soil water movement was detected at 3. m downslope following rainfall events of 60-70. mm/day. The 0.2-0.6. m soil layer benefited more from the lateral soil water movement at all the farms. Our results suggest that dead level contours have to be constructed at 3-8. m spacing for crops to benefit from the captured rainwater. It is probably worth exploring strip cropping of food and fodder crops on the downslope of the dead level contours and infiltration pits using the current design of these between-field structures. With the advent of in situ rainwater harvesting techniques included in some conservation agriculture practices it will benefit smallholder cropping systems in semi-arid areas if these between-field structures are promoted concurrently with other sustainable land management systems such as conservation agriculture. © 2011 Elsevier Ltd.


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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