不同放牧制度下奶牛对多年生黑麦草／白三叶草地土壤特性的影响

本项试验在湖南南山牧场进行，旨在研究不同放牧制度下奶牛对多年生黑麦草／白三叶人工草地土壤物理和化学特性的影响。表明，放牧制度对黑麦草白三叶人工草地土壤的物理结构有一定影响。轮牧草地上土壤的容重较小，含水量较高，孔隙度增加；而连续放牧使土壤的紧实度增加，容重上升，透气为差，含水量下降；放牧对土壤物理特性的影响将随着土 深度的增加而减轻，轮牧草地的土壤多数养分尤其是速效和速效钾的含量均高于连牧草地。

Effects of Different Grazing Systems for Dairy Cows on Soil Characteristics of Perennial Ryegrass/White Clover Sward

The effects of dairy cows grazing on physical and chemical characteristics of soil of Lolium perenne/Trifolium repens swards were studied at Nanshan Ranch in Hunan during May to October, 1984.The result showed that grazing system could influence the soil physical structure. The lower soil bulk density,higher water content and more soil prorosity were existed under rotational grazing, but tht soil bulk density increased, water content and soil prorosity decreased under continuous grazing. The impact of grazing system on soil physical characteristics decreased with the increament of soil depth. The contents of most nutrients in the soil for rotatlonal grazed sward were higher than those of continuous grazed sward, especially the contents of available phosphorus and potasium.