Abstract
Aims Rangelands serve as key reservoirs of soil organic carbon (C) and play a crucial role in global C cycling. High-density grazing (HG) systems gained popularity in South Africa, promoting sustainable grazing and higher animal productivity per unit area. HG systems typically implement intense grazing pressure followed by extended resting periods for vegetation recovery, in contrast to conventional rotational grazing systems (CG) applying lower grazing pressure over a longer period. This study quantified soil and vegetation differences between HG and CG systems and aimed to gain insights into underlying mechanisms. Methods A fence-line comparison was performed on 11 sites in four semi-arid, summer rainfall regions: North West, Eastern Cape, eastern Free State, and central Free State. Each site represented two neighbouring commercial rangeland farms (HG vs CG). Soil samples were collected along fence-lines between the two farms and analysed for bulk density, aggregate stability, total C and nitrogen, organic material, active C, soil microbial biomass. Vegetation indicators, including root biomass, veld condition, and Normalized Difference Vegetation Index (NDVI) were also assessed. Results HG had positive effects on soil and vegetation, especially in fine-textured soils and wetter climates. Exudates from improved grass roots under HG systems enhanced soil microbial activity and C sequestration. However, a significantly negative impact of increased stocking rates on bulk density, particularly in deeper soil layers, was found across regions. Conclusions This study highlights the effects of grazing systems on soil and vegetation dynamics, emphasizing the importance of site-specific conditions in shaping these effects.