Effects of different management regimes on soil erosion and surface runoff in semi-arid to sub-humid rangelands

Abstract

Over one billion people's livelihoods depend on dry rangelands through livestock grazing and agriculture. Livestock grazing and other management activities can cause soil erosion, increase surface runoff and reduce water availability. We studied the effects of different management regimes on soil erosion and surface runoff in semi-arid to sub-humid rangelands. Eleven management regimes were assessed, which reflected different livestock grazing intensities and rangeland conservation strategies. Our review yielded key indicators for quantifying soil erosion and surface runoff. The values of these indicators were compared between management regimes. Mean annual soil loss values in the ‘natural ungrazed’, ‘low intensity grazed’, ‘high intensity grazed rangelands’ and ‘man-made pastures’ regimes were, respectively, 717 (SE = 388), 1370 (648), 4048 (1517) and 4249 (1529) kg ha−1 yr−1. Mean surface runoff values for the same regimes were 98 (42), 170 (43), 505 (113) and 919 (267) m3 ha−1 yr−1, respectively. Soil loss and runoff decreased with decreasing canopy cover and increased with increasing slope. Further analyses suggest that livestock grazing abandonment and ‘exotic plantations’ reduce soil loss and runoff. Our findings show that soil erosion and surface runoff differ per management regime, and that conserving and restoring vulnerable semi-arid and sub-humid rangelands can reduce the risks of degradation.