放牧压力对人工靴生产能力的影响

The Effects of Grazing Pressure on Sown Pasture Productivity

放牧压力作为放牧系统的一种外界干扰力对草地初级生产过程能产生强烈影响.人工草地在30、60和120头牛/公顷/天的放牧压力和连续刈割下。草地群落中种群竞争、牧草叶片生长和叶面积指数、牧草生物量增长速率、草地累积产量、放牧采食量和采食率均有显著差异.当草地净初级生产量在10000—12000公斤干物质/公顷/年时,用60头牛/公顷/天的放牧压力利用草地饲草的效果最佳.

The variation influencing sward development,herbage leaf growth,LAI,average growth increment rate,accumulative yields,utilization,defoliation and grazing rate by al- Ioting 30,60 and 120 cattle ha^(-1)day^(-1)in grazing treatments as well as the harvest on the sown pasture of a high elevated hillock in subtropics of China were studied from 1985 to 1986.The results have been indicated by the author that the characters of plant growth and development of sown pasture could be influenced obviously by grazing pressure.The amount of white clover seeds and local weeds infested in swards increased as the grazing pres- sure was raised gradually.The leaf appearing intervals of white clover and ryegrass did not differ from among the grazing treatments,but the LAI of ryegrass was shown increased with the increasing trends of grazing pressure,while the LAI of weeds,in turn,decreased great- ly.The average rate of growth increment in swards and white clover there fell strongly during August.The accumulative yields of pasture from grazing treatments were much greater than those of clipping and their variation was obvious during the autumn when observed.The utili- zation,defoliation and grazing rate of swards were affected by grazing pressure too.The optimum grazing pressure with 60 cattle ha^(-1)day^(-1)for the yield of 10,000 to 12,000 DM kg ha^(-1)day^(-1)in sown pasture was pointed out by the author as a reasonable sugges- tion applied for use in production.