Talore D.G., Tesfamariam E.H., Hassen A., Du Toit J.C.O., Klumpp K., Soussana J.F.
Department of Animal and Wildlife Sciences, University of Pretoria, Private bag 0083, Hatfield, Pretoria, South Africa; Department of Plant Production and Soil Science, University of Pretoria, Hatfield, Private bag 0002, Pretoria, South Africa; Grootfontein Agricultural Development Institute, Middelburg, Eastern Cape, South Africa; INRA, Grassland Ecosystem Research (UR874), Chemin de Beaulieu, Clermont Ferrand Cedex 2, France; French National Institute for Agronomic Research, INRA, Paris, France
Talore, D.G., Department of Animal and Wildlife Sciences, University of Pretoria, Private bag 0083, Hatfield, Pretoria, South Africa; Tesfamariam, E.H., Department of Plant Production and Soil Science, University of Pretoria, Hatfield, Private bag 0002, Pretoria, South Africa; Hassen, A., Department of Animal and Wildlife Sciences, University of Pretoria, Private bag 0083, Hatfield, Pretoria, South Africa; Du Toit, J.C.O., Grootfontein Agricultural Development Institute, Middelburg, Eastern Cape, South Africa; Klumpp, K., INRA, Grassland Ecosystem Research (UR874), Chemin de Beaulieu, Clermont Ferrand Cedex 2, France; Soussana, J.F., French National Institute for Agronomic Research, INRA, Paris, France
Background and aims: The Karoo biomes of South Africa are major feed resources for livestock farming, yet soil nutrient depletion and degradation is a major problem. The objective of this study was to assess impacts of long-term (>75 years) grazing during spring (SPG), summer (SUG), winter (WG) and exclosure (non-grazed control) treatments on soil nutrients, penetration resistance and infiltration tests. Methods: A soil sampling campaign was carried out to collect soil to a depth of 60 cm to analyse bulk density, soil physical and chemical parameters as well as soil compaction and infiltration. Results: Generally, grazing treatments reduced soil organic C (SOC) stocks and C:N ratios, and modified soil properties. There was higher SOC stock (0.128 Mg ha−1 yr−1) in the exclosure than in the SPG (0.096 Mg ha−1 yr−1), SUG (0.099 Mg ha−1 yr−1) and WG (0.105 Mg ha−1 yr−1). The C:N ratios exhibited similar pattern to that of C. From the grazing treatments, the WG demonstrated 7 to 10 % additional SOC stock over the SPG and SUG, respectively. Conclusions: Short period animal exclusion could be an option to be considered to improve plant nutrients in sandy soils of South Africa. However, this may require a policy environment which supports stock exclusion from such areas vulnerable to land degradation, nutrient and C losses by grazing-induced vegetation and landscape changes. © 2015, Springer International Publishing Switzerland.