Nitrogen fertilization, stocking rate and rotational grazing effects on steers grazing Pennisetum clandestinum

Abstract

Kikuyu pastures at the Ukulinga research farm near Pietermaritzburg were fertilized with 150 and 300 kg nitrogen (N) ha⁻¹ in the summer periods of 1985–86 and 1986–87, and were continuously grazed with steers at stocking rates of 5.4, 8.0 and 10.7 steers ha⁻¹. In the second season the high N level pasture was also grazed under 12‐paddock rotational grazing at stocking rates of 5.4, 8.0 and 13.4 steers ha⁻¹. In the first season the high N level provided higher (P≤0.05) animal weight gains, but there was no difference between N levels in animal weight gain during the second season. Rotational grazing provided higher weight gains than continuous grazing in the second season. The increased weight gains obtained from high N fertilization and rotational grazing were probably caused by higher forage availability rather than higher forage quality.

Kikuyu weidings op die Ukulinga navorsings plaas naby Pietermaritzburg het 150 en 300 kg stikstof (N) ha⁻¹ in die somerperiodes van 1985–86 en 1986–87 ontvang, en was met aanhoudende beweiding op veebeladings van 5.4, 8.0 en 10.7 ossies ha⁻¹ gestel. Gedurende die tweede seisoen was weidings wat die hoë N peil ontvang het ook met 12‐kamp wisselbeweiding by veebeladings van 5.4, 8.0 en 13.4 ossies ha⁻¹ bewei. Lewende massatoename was hoër (P≤0.05) vir die hoër N peil gedurende die eerste seisoen, maar daar was geen verskil tussen N peile in lewende massatoename gedurende die tweede seisoen nie. ‘n Hoër massatoename het by wisselbeweiding as by aanhoudende beweiding in die tweede seisoen voorgekom. Die hoër massatoename wat by die hoë N peil en wisselbeweiding voorgekom het, kan waarskynlik aan hoër weidingsbeskikbaarheid eerder as aan hoër weidings kwaliteit toegeskryf word.

Additional index words:

• Average daily gain
• herbage availability
• kikuyu