放牧强度对宁夏荒漠草原植物群落结构及草地生产力的影响

以宁夏盐池县的荒漠草原区为试验地,以现场试验为手段,研究放牧强度(1.50只/hm2、0.75只/hm2、0.50只/hm2、0只/hm2)对荒漠草原植物群落结构及草地生产力的影响。结果表明:随着放牧强度的增加,植物群落优质牧草的重要值明显下降,毒草及家畜厌食植物的重要值明显上升;植物群落总盖度呈下降趋势,植物群落多样性呈现先增加后降低的趋势;草地生产力呈下降趋势,当放牧强度达到1.50只/hm2时,家畜的采食量超过了50%,草产量比封育地下降了54.9%。最后,根据草场资源可持续发展利用原则提出了宁夏荒漠草原合理的放牧强度以0.75只/hm2为宜。

Effect of grazing intensities on plant community structure and grassland productivity in desert steppe of Ningxia

The aim of this study was to evaluate the effect of grazing intensities(1.50 sheeps/hm2,0.75 sheeps/hm2,0.50 sheeps/hm2,0 sheeps/hm2) on plant community structure and grassland productivity in desert steppe of Ningxia Province.The results showed that with the increase of grazing intensity,importance-value of high quality forage decreased obviously,while those of noxious weeds and unpalatable plants increased,and the plant diversity first increased then decreased.The total vegetation coverage decreased with the increase of grazing intensity,there was also a decrease in grassland productivity,the forage yields of pasture declined to 54.9 % of restored grassland when the grazing capacity reached 1.5 sheeps/hm2 and the intake rate of the total forages exceeded by 50%.Results indicated that the reasonable grazing capacity of the studied pasture land is proposed to be 0.75 sheeps/hm2 according to the principle of sustainable development.