【摘要】 对内蒙古科尔沁沙质草地 5年的放牧试验结果表明 ,过牧对草地生态系统的危害很大 ,连续 5年过牧使草地生物多样性、植被盖度、高度和初级生产力分别较禁牧区低 87 9%、82 1%、94 0 %和 5 7 0 % ,草地现存生物量仅为禁牧区的 2 1% ,土壤粘粒、C、N含量和微生物、小型动物数量也较之降低 6 0 %、31 9%、2 5 0 %、95 0 %和 75 9% ,地表紧实度提高 2 74 0 % ,特别是次级生产力从第 3年转为负增长 ,使草地产出功能完全破坏 .封育对沙质草地十分有益 ,封育 5年草地各项指标均有大幅度增加 .轻牧和中牧下的植被盖度、高度、土壤状况处于禁牧区和重牧区之间 ,其中轻牧区植被情况要好于中牧区 ,但次级生产力低于中牧区 .根据多年调查和本次试验结果可以认为 ,内蒙古东部半干旱沙质草地牧草的利用率应为4 5 %～ 5 0 % ,草地载畜量以 3～ 4羊单位·hm-2 比较适宜更多还原

【Abstract】 This experiment was carried out for 5 years in Horqin sandy land,Inner Mongolia,which had 4 treatments:Non-grazing (NG),light grazing (LG),moderate grazing (MG) and over grazing (OG).The results showed that different grazing intensities resulted in different development trend of the pasture ecosystem,of which,the injury of OG on pasture ecosystem was very great.The plant diversity,vegetation coverage,plant height and primary productivity under continuous overgrazing for 5 year were 87.9%,82.1%,94.0% and 57.0%,respectively,lower than those in NG.The biomass on the OG pasture was only 2.1% of NG,and the contents of soil clay,C and N as well as the quantities of soil microbes and small animals in OG were respectively 6.0%,31.9%,25.0%,95 0% and 75.9% lower than those in NG,but the soil hardness was raised by 274.0%.Especially,the secondary productivity of the pasture became negative from the third year,and the productive foundation of the pasture ecosystem was completely destroyed.Non-grazing was beneficial to pasture,and enclosure caused an increase in vegetation coverage,plant height and primary productivity.The vegetation coverage,plant height and soil status in LG and MG were not as good as those in NG,but were stable and didn’t show worsening trend.Based on the above results,it’s considered that on the sandy pasture in the semi-arid area of Inner Mongolia,the rational grass utilization ratio is 45%～50%,and the suitable loading capacity is 3～4 sheep unit·hm -2.更多还原