The Analysis of Climate-induced Feed Gaps in Arid and Semi-arid Southern African Regions: The Case of The Limpopo Province-South Africa

Abstract

In the southern areas of Africa, climate hazards such as prolonged drought are among the phenomena that have negatively affected the farming systems. In relation to livestock, productivity is constrained by the shifts in vegetation dynamics that translate into feed gaps. Therefore, opportunities to cope with seasonal or interannual feed gaps for smallholder livestock keepers are urgently needed. Against this background, we investigated one of the most susceptible provinces to drought risks in South Africa, the Limpopo province, the seasonal occurrence of feed gaps. Firstly, we used a survey technique to derive specific on-farm information regarding the seasonal feed availability and the current adaptation options as perceived by the rural smallholder farmers. We linked the survey information to vegetation-modeled data of the surveyed sites using aDGVM (adaptive Dynamic Global Vegetation Model) and elemental nutrient analysis of grazed grasses during the winter period. We analyzed these data to draw conclusions on the patterns of feed gaps across farm types (e.g. livestock only, mixed crop-livestock) and locations (warm arid, warm semi-arid, and cool semi-arid). Secondly, to have a broader picture of the available forage resources, we calculated the forage balance of the study province in relation to cattle keeping. Here, we linked the results to the assessment of the land use types (soil nutrient analysis of rangelands and arable lands) and crude protein levels of available feeding resources in periods of feed gaps. We found that a negative forage balance in the province, and degraded land use types may be strong drivers of the seasonal feed gaps. Thirdly, additional on-farm data (e.g. cattle feces samples, cattle tail hair) were analyzed for the C and N isotope signatures. These samples were analyzed to assess and identify the triggers of feed gaps and their impacts on the farming systems. Here, we used isotopic signature techniques (δ15N and δ13C ) to highlight livestock nutritional stress/differences across the locations and farm types. Stable isotopes are an important tool that can be used to describe and quantify different diet sources. Particularly, hair tissues contain dietary archive information that can temporally and spatially inform us on the environment. In line with this, the results confirmed that feed when available to livestock is usually “protein-deficit” which may be the cause of feed gap impacts such as animal weight losses. The results indicated that feed gaps follow strong seasonal patterns and suggest that strategies to cope need to be context-specific. Furthermore, the results of this study set a strong foundation to inform drought risk management in a smallholder livestock farming context. The results can serve as a step toward developing context-specific management options for improved livestock systems. Also, this study calls for further mixed crop-livestock systems research focusing on a whole-farm modeling approach to evaluate the system against climate scenarios and different management options.