放牧强度对荒漠草原二裂委陵菜根系构型的影响

Effects of grazing intensity on root architecture of Potentilla bifurca in desert steppe

通过对内蒙古四子王旗荒漠草原未放牧(CK)、轻度放牧(LG)、中度放牧(MG)和重度放牧(HG)群落中二裂委陵菜根系构型参数以及相应土壤水分、容重的分析,研究了不同放牧强度对荒漠草原二裂委陵菜根系构型的影响。结果发现:1)随着放牧强度的增大,二裂委陵菜根系构型参数均呈减小的趋势,以HG区各项参数值最小,放牧强度在0.91到1.82之间是二裂委陵菜根系长度、根直径、根尖数和群落植被盖度等参数产生显著差异的分界段;2)在各项参数中,放牧强度对二裂委陵菜根系表面积的影响最大;3)随着放牧强度的增大,土壤含水量和土壤容重分别出现降低和增加的趋势是导致根系小型化的因素之一。

The root architecture parameters of Potentilla bifurca and the related soil water content and bulk density were analyzed in no grazing（CK）,light grazing（LG）,middle graze（MG） and heavy grazing（HG） plant community in desert steppe at SiZiWang Banner in Inner Monglia.The effects of grazing intensitys on the root architecture of Potentilla bifurca were studied.Following conclusions were gotten： 1） With the increment of grazing intensities,the root length,root diameter,root surface area,root volume and root tips number were decreased.The minimium of all paprameters were found in the HG community.Grazing intensities between 0.91 and 1.82 were found to be the transition section that the root length,root diameter,root tips number and vegetation coverage of Potentilla bifurca changed greatly.2） Grazing intensities mainly influenced the root surface area of Potentilla bifurca among all the parameters of root architecture.3） With the increments of grazing intensity,the soil water content was decreased and bulk density was increased,which was the reason for the root miniaturization.