放牧强度、放牧草丛高度对多年生黑麦草、白三叶混播草地产量及草地组成的影响

在南方业热带海拔1200米左右的中山区,在以多年生黑麦草与白三叶混播的草地上进行了研究,试验分模拟放牧和直接放牧两种处理。放牧试验为放牧强度的单因子试验,选择了三个水平的放牧强度,即放牧后草地牧草留槎高度为3cm、5cm 及7cm。模拟放牧试验为放牧强度与放牧草丛高度的两因子试验,各选三个水平,即强度为牧草留槎高为3cm、5cm、7cm,放牧草丛高度为15cm、20cm、25cm。通过三年(1987—1989)的试验表明,不同放牧强度、放牧草丛高度对草地组成、牧草产量的影响明显,在当地生态条件下,适宜的放牧强度是放牧后草地留槎在5cm 左右,放牧草丛高度在20cm 左右,这时的牧草采食率在55%右左。

EFFECTS OF GRAZING INTENSITY AND HEIGHT OF GRASS BEFORE GRAZING ON FORAGE YIELD AND GRASSLAND COMPOSITION OF MIXTURE OF WHITE CLOVER AND PERENNIAL RYEGRASS

The experiment was carried out from 1987 to 1989 on a mixture of white clover and perennial ryegrass at 1200m above sea level in southern China under two situations:grazing and simulated grazing.The grazing testwas a single-factor experiment designed for three levels of grazing intensity with the stubble height of 3,5,7cm respectively.The simulated grazing test was a two factors experiment for three levels of grazing intensity (stubbleheight of 3,5,7cm) and the height of grass before grazing (15,20,25cm) The results of the experiment have shown that grazing intensity and the hei-ght of grass before grazing have a distint influence on grassland composition and forage yield.Under local ecological condition the optimum grazing inten-sity is about 5cm for stubble height and height of grass before grazing should be controled as to start grazing when the grass is about 20cm high.Un-der this regime,the grazing rate of the grassland is approximately 55%.