放牧绵羊对亚热带人工草地地上生物量的影响

本文在放牧和封育条件下研究了多年生黑麦草和白三叶人工草地地上部第一性生产力及其形成的规律。结果表明，黑麦草生物量和地上生物量的形成规律为双峰型，而白三叶则为单峰型。在放牧采食率为69、55、45％和不放牧条件下，人工草地地上净第一性生产力分别为1210．9、1076．4、987．9和555．2g／m2，其中多年生黑麦草的地上净第一性生产力分别为899.8、777．0、746．0和372．0g／m2。白三叶分别为311．1、299．4和207．2g／m2。放牧地较封育地获得较大的净第一性生产力。试验结果表明，本试验设计的70％采食率是该混播草地较适合的放牧强度。

Effect of Grazing Sheep on Aboveground Biomass in Subtropical Pasture

The dynamics and regulation of biomass accumulation under grazing in Lolium perens-Trifolium repens mixed pasture were studied. The results showed that the phenophase of two species is consistent. The growth model of total biomass and perennial ryegrass biomass are double-peak curve, while the white clover has just monopeak. The net primary production were increased by stocking rate. They were 1210. 9, 1076. 4, 987. 9 and 555. 2 g/m under stocking rates 69%, 55%, 45% and no grazing. As the same, the perennial ryegrass were 899. 8, 777. 0, 746. 0 and 372.0 g/m2; the white clover were 311.1, 299.4, 241. 9 and 207. 2g/m2. The total net primary production of the mixed pasture were affected obviously by stocking rate, especially of white clover. The 70% stocking rate was suitalbe for the mixed pasture.