Pauline Chivenge

The Potential Role of Neglected and Underutilised Crop Species as Future Crops under Water Scarce Conditions in Sub-Saharan Africa.

Modern agricultural systems that promote cultivation of a very limited number of crop species have relegated indigenous crops to the status of neglected and underutilised crop species (NUCS). The complex interactions of water scarcity associated with climate change and variability in sub-Saharan Africa (SSA), and population pressure require innovative strategies to address food insecurity and undernourishment. Current research efforts have identified NUCS as having potential to reduce food and nutrition insecurity, particularly for resource poor households in SSA. This is because of their adaptability to low input agricultural systems and nutritional composition. However, what is required to promote NUCS is scientific research including agronomy, breeding, post-harvest handling and value addition, and linking farmers to markets. Among the essential knowledge base is reliable information about water utilisation by NUCS with potential for commercialisation. This commentary identifies and characterises NUCS with agronomic potential in SSA, especially in the semi-arid areas taking into consideration inter alia: (i) what can grow under water-scarce conditions, (ii) water requirements, and (iii) water productivity. Several representative leafy vegetables, tuber crops, cereal crops and grain legumes were identified as fitting the NUCS category. Agro-biodiversity remains essential for sustainable agriculture.

Building climate change resilience through adaptation in smallholder farming systems in semi-arid Zimbabwe

Purpose This study aimed to determine factors that increase resilience and cause smallholder farmers to adapt better to climate change and vulnerability. Design/methodology/approach In this study, the authors used the vulnerability to resilience model and binary logit model to analyse the factors influencing household decisions to adapt. Findings Households with increased access to climate information through extension services were likely to have better adaptation abilities. It was also shown that younger farmers were likely to adapt to climate change given their flexibility to adopt new techniques and their access and use of modern information and technology. Larger households were found to have higher probability of adapting as most adaptation strategies are labour intensive. Household’s possession of livestock and access to credit significantly enhanced adaptation. However, households with higher farm income have lesser incentives to adapt to because their current farming practices might already be optimum. Research limitations/implications Given that most of the smallholder farmers are vulnerable, such as women-headed households and the elderly, who are labour constrained, there is need for research and development of labour saving technologies to increase resilience to climate change and vulnerability. Originality/value These findings underscore the importance of enabling farmer access to information and better technologies which enable them to increase adaptive capacity and resilience.

Changes in carbon and nutrient fluxes from headwaters to ocean in a mountainous temperate to subtropical basin

Water erosion provides major links in global cycles of carbon (C), nitrogen (N) and phosphorus (P). Although significant research on erosion mechanisms has been done, there is still little knowledge on C, N and P fluxes across landscapes to the ocean and their controlling factors in subtropical climates. A four-year study quantifying and comparing particulate and dissolved C, N and P from multiple scales (microplot, plot, microcatchment, subcatchment, catchment, sub-basin and basin) was performed in Thukela basin (≈30 000 km2), South Africa. The basin climate was largely subtropical-humid (mean annual precipitation: MAP > 980 mm yr-1), but temperate (MAP > 2000 mm yr-1) on the highlands. Open grassland, cropland and bushland were the major land uses. On average, 65, 24 and 4 g m-2 yr-1 C, N and P were displaced from original topsoil positions, but only 0.33, 0.005 and 0.002 mg m-2 yr-1 were, respectively, exported to the ocean. The fluxes decreased by 95, 97 and 84%, respectively, from plot to microcatchment outlet; and decreased further in downstream direction by >99% from microcatchment to basin outlet. The hillslope (microplot to microcatchment) fluxes correlated strongly with rainfall parameters. Particulate contributions dominated hillslope fluxes at 73, 81 and 76% of total annual C, N and P, respectively. Although particulate C dominated in the microcatchment-catchment reach (55%), N (54%) and P (69%) were dominated by dissolved forms. The lower basin zone was dominated by dissolved flux contributions at 93, 81 and 78% for C, N and P for the sub-basin outlet. These results suggested spatially varying drivers of C, N and P losses from the landscape to the ocean, via the river network. Deposition was envisaged the dominant hillslope level loss process, which gradually gave way to mineralisation and biotic uptake in the river network as flux contributions shifted from being predominantly particulate to dissolved forms.

Contextual vulnerability of rainfed crop-based farming communities in semi-arid Zimbabwe: A case of Chiredzi District

Purpose The purpose of this paper is to assess smallholder farmers’ vulnerability to climate change and variability based on the socioeconomic and biophysical characteristics of Chiredzi District, a region that is susceptible to the adverse effects of climate change and variability. Design/methodology/approach Vulnerability was assessed using the Vulnerability to Resilience and the Climate Vulnerability and Capacity frameworks. Findings The major indicators and drivers of vulnerability were identified as droughts, flash floods, poor soil fertility and out-migration leaving female- and child-headed households. From sensitivity analysis, it was shown that different areas within the district considered different biophysical and socioeconomic indicators to climate change and variability. They also considered different vulnerability indicators to influence the decisions for adaptation to climate change and variability. Originality/value The results of this study indicate that the area and cropping systems are greatly exposed and are sensitive to climatic change stimuli, as shown by the decline in main cereal grain yield. These results also showed that there is a need to define and map local area vulnerability as a basis to recommend coping and adaptation measures to counter climate change hazards.

Climate smart crops for food and nutritional security for semi-arid zones of Zimbabwe

Southern Africa smallholder farmers continue to be the most affected by the challenges of climate change and variability. The variability of climate demands the use of a variety of agronomic strategies and crop choices. Traditional drought tolerant cereal crops such as sorghum and millets are often chosen when drought seasons are anticipated. However, there are certain crops, originating elsewhere, that could help the smallholder farmers increase diversity of crops that can be grown in changed climates. Trials were conducted to test a basket of known and introduced climate smart crops in the field. The cereal crops tested were maize, sorghum, pearl and finger millet, and legumes: tepary bean ( Phaseolus acutifolias ), cowpea ( Vigna unguiculata ), Bambara nut ( Vigna subterranea ), groundnut ( Arachis hypogaea ) and pigeon pea ( Cajanus cajan . A second experiment was conducted to determine the effects of inorganic fertilizer and rhizobium inoculation on the growth and grain yield of field grown tepary bean. Both experiments were laid out in a randomized complete block design with three replications. Due to drought conditions during the growing season, cereal crops could not produce grain yield, as there was no grain filling. Despite this, cereal biomass was 5t ha -1 for maize, followed by sorghum (1.3t ha -1 ) and millet (1.2t ha -1 ). Legume crops produced grain with cowpea yielding 568.1kg ha -1 of grain, followed by tepary bean (245.9kg ha -1 ) and common bean (227kg ha -1 ). This is important for food, nutrition and health security of smallholder communities. Tepary bean inoculated with rhizobium and had fertilizer applied produced higher grain yield than those without fertilizer or rhizobium inoculant (P≤0.05). In conclusion, resource poor farmers, affected by drought effects of climate change, can adopt both cereals and legumes climate smart crops, in order to create food and nutritional security. This is crucial for food and nutritional security of vulnerable households affected by climate change and variability. Key words: tepary bean, climate smart crop, drought, smallholder farmers