B.U. LÜTGE¹, M.B. HARDY² and G.P. HATCH¹

¹Department of Grassland Science, University of Natal, Republic of South Africa
²Cedara Agricultural Development Institute, Pietermaritzburg, Republic of South Africa

Abstract

A study to characterise selected sward and soil properties in grazed patches and ungrazed non-patches was conducted in a humid grassland of South Africa. Patches and non-patches could be distinguished in terms of soil moisture, soil depth, certain soil nutrients, hydraulic conductivity, species composition and basal cover. Soil moisture (P < 0.01) and soil depth (P < 0.05) were lower and P and K were higher (P < 0.05) in patches than non-patches. Hydraulic conductivity was also higher in non-patches than patches at supply potentials of -25 mm (P < 0.01) and -35 mm (P < 0.05). Patches were characterised by a high proportion of Microchloa caffra, Heteropogon contortus, Eragrostis curvula, Sporobolus africanus and Digitaria tricholaenoides, and non-patches by Trachypogon spicatus, Alloteropsis semialata, Eulalia villosa, Diheteropogon amplectens and sedge and spring-aspect forb species. Patch grazing also seemed to increase mortality of tussocks in the patches. The potential for patch grazing to be the focus for overall range degradation is discussed.