牧压和肥力对亚热带山地牧草净生产的影响

在亚热带山地湿润环境条件下, 研究牧压和土壤肥力对人工草地净生产的影响。三年试验结果表明, 绵羊在轮牧下, 产草量和磷肥对全年及各月牧草净生产具有显著影响。禁牧时, 夏季地上生物量积累到一定程度后, 只有很少量的净生产。放牧时, 产草量在1000kgDM/hm²左右时, 净生产最大, 当产草量低于300kgDM/hm²以下时, 净生产量则降低。每年施一次 P2O536～ 60kg/hm², 可以显著增加牧草净生产, 尤以春末夏初时施肥更为显著。最低产草量出现在不施肥处理

Effect of Grazing Pressure and Soil Fertility on Net Pasture Production of Subtropical Mountain

The effect of grazing and fertility on net pasture production(net herbage accumulation)was studied experimentally in a subtropical mountain area located in Western Hubei Province.The result of three years from 1997 to 1999 showed significant effect of post grazing residual and P level on seasonal and annual net production of the sown pasture under sheep rotational grazing.The pasture without any grazing disturbance had little net production after reaching a high level in summer.Net production was maximized by grazing management with a residual around in net production.Phosphorus applied annually at 36～60 kg/hm² resulted in markedly increased pasture net production,particularly during late spring/early summer period when there is a high potential of pasture growth.The lowest production occurred where no fertilizer was applied.