Rangeland characteristics of a supercritically degraded landscape in the semi-arid area of South Africa

Abstract

The objective of this study was to investigate rangeland condition in a semi-arid area with doubling erosion rates. Work was conducted using aerial photographic analysis and field investigations were conducted using 10 paired 20 x 20 m plots and 2 1 x 1 m quadrats randomly located with each plot. Degraded sites showed significant differences in soil compaction but not in soil water infiltration time. Degraded sites were characterized by absence of woody plant cover. Grass cover and litter cover were lower on degraded plots than on undegraded plots. Bare soil cover was more extensive on degraded plots than on undegraded plots. The sheet eroded plots had very low woody cover, grass cover and litter cover, low organic matter, low porosity and high soil density. Soil density on degraded sites was significantly different from undegraded sites (t test; t =3.482; df =18; p<0.05). Assessing rangeland characteristics and erosion risk in the study is part of a global management of agricultural soils that should aim at increasing productivity. Key words: Umfolozi catchment, soil erosion, semi-arid landscapes, range-condition.