放牧对呼伦贝尔典型草原植物生物量分配及土壤养分含量的影响

在内蒙古呼伦贝尔草原克鲁伦河流域选取轻度、中度和重度3个放牧区研究植物地上和地下生物量、根冠比及土壤有机质、氮、磷等养分含量对放牧强度的响应。结果表明：重度放牧区的地上生物量（89.73 g·m^-2）显著低于轻度（565.61 g·m^-2）和中度放牧区（488.92 g·m^-2），地下生物量（1 029.90 g·m^-2）则显著高于轻度（604.92 g·m^-2）和中度放牧区（418.38 g·m^-2）。重度放牧区的根冠比为11.54，显著高于轻度（1.11）和中度放牧区（0.89）。土壤有机质及各养分含量随着放牧强度的增加先显著降低而后显著增大，中度放牧区的养分含量最低。

Effects of Grazing on Biomass Allocations and Concentrations of Soil Nutrients in the Grassland of Inner Mongolia

We carried out this study on the basin of Kherlen river in the Hulunbeir grassland of Inner Mongolia by studying the aboveground and belowground biomass, root to shoot ratio(R/S), and the concentrations of SOM as well as other soil nutrients in response to three levels of grazing pressure:light grazing(LG), moderate grazing(MG), heavy grazing(HG). Our results showed that grazing intensity could significantly influence plant biomass, R/S, the concentrations of SOM and other soil nutrients in this grassland ecosystem. The aboveground biomass of HG(89.73 g·m^-2) was significantly lower than those of LG(565.61 g·m^-2) and MG(488.92 g·m^-2), while the belowground biomass and R/S of HG(1 029.90 g·m^-2, 11.54) were significantly higher than those of LG(604.92 g·m^-2, 1.11) and MG(418.38 g·m^-2, 0.89). The concentrations of SOM and other soil nutrients were first decreased and then increased with the grazing intensity increased, the lowest nutrient concentrations were achieved at MG.