Effect of soil type on spatial distribution and nutritive value of grass species growing in selected rangelands of South Africa.

Abstract

The distribution and status of grass species is essential for sustainable management of rangelands. Therefore, this study assessed the spatial distribution and nutritive value of grass species as influenced by soil type in selected rangelands of the North West province of South Africa. Grass species were harvested from four communal areas (clay loam and red brown sand soil types) using three transects per study area. Each transect was sub-divided into near (0.5–0.7 km), middle (0.70–1.4 km) and far sub-transects (1.4–2.2 km) based on distance from homesteads. Within each sub-transect, 10 m × 10 m homogeneous vegetation units (HVU) were marked and quadrats (1 m2) were randomly placed within each HVU to sample soil and grasses. Species composition, abundance, biomass and nutritive value of grass species were measured. Only 21% of grasses identified in the study areas were determined to be of high grazing value. Aristida species were more common and dominant in both soil types. Eragrostis cylindriflora 2 Hochst. had higher crude protein content and the highest in vitro ruminal dry matter degradability after 24 and 48 hours. Thus, E. cylindriflora was the most valuable grass species for livestock farming in the study areas and could be earmarked for rangeland restoration.