Long-term effects of different rotational grazing schedules on the productivity and floristic composition of Tall Grassveld in KwaZulu-Natal

Abstract

Nine simulated rotational grazing systems, comprising combinations of three different periods of occupation (2, 10 and 20 days) and three periods of absence (20, 40 and 60 days), were applied to Tall Grassveld for 24 years (1967-1991), using sheep. All camps were rested every fourth year during which recovery growth yields were measured. Differences in floristic composition between camps at the end of the trial were small and were associated with spatial variations in composition on the experimental site rather than with the applied grazing treatments. Although palatable grasses, such as Themeda triandra and Tristachya leucothrix, were still dominant in 1991, the unpalatable grass Aristida junciformis increased in abundance in all treatments during the last seventeen years of the trial. The extent of this increase did not, however, vary (P > 0.05)between treatments. The mean recovery yield over all rest years did not differ (P > 0.05)between treatments because of inconsistencies in treatment effects between years, particularly during the last three grazing cycles (1977-1988). It is concluded that multi-camp systems employing short periods of occupation and long rests between grazings, cannot be justified in terms of their purported ability to improve plant productivity and veld condition. However, a limited degree of camping may facilitate management of temporal and spatial variations in vegetation composition and productivity.

Keywords: abundance; aristida junciformis; botany; floristic composition; grasses; grassveld; grazing management; grazing systems; grazing treatments; multi-camp systems; non-selective grazing; period of absence; period of occupation; pietermaritzburg; productivity; recovery; rotational grazing; sheep; south africa; spatial variation; tall grassveld; themeda triandra; tristachya leucothrix; ukulinga research station; vegetation composition; veld condition; yield

African Journal of Range & Forage Science, 13(1): pp. 24-28