Dry matter yield of herbaceous rangeland plants and livemass gain of Tswana steers in eastern Botswana in response to stocking rate and phosphorus supplementation

Abstract

Tswana steers were continuously grazed at stocking rates of 3, 6, and 9 ha LSU -1 in two blocks, and steers in one block were supplemented with phosphorus. Dry matter yield of herbaceous rangeland plants was measured at the end of each growing season from 1984 to 1990 except in 1986, whilst steer livemass was measured monthly. Steers entered the trail at the beginning of the growing season and remained on the trial for three years and two groups of steers were evaluated in the study. Dry matter yield of Digitaria spp. and annual grasses showed no response to stocking rate. Panicum maximum and Eragrostis regidior were the most responsive species, increasing with a decreased stocking rate. Phosphorus supplement was advantageous during drought periods at stocking rates higher than 9 ha LSU^-1. Livemass gain increased with decreased stocking rate regardless of phosphorus supplements.

Keywords:annual grasses; botany; botswana; degradation; digitaria; drought; dry matter yield; grasses; live mass gain; mahalapye district; overstocking; panicum maximum; phosphorus; rainfall response; rangeland; stocking rate; stocking rates; yield

African Journal of Range & Forage Science, 10(2): pp. 103-107