高寒草原季节牧场生物量对土壤水分的响应

Relationship between soil moisture and biomass in grazing land of wapiti on an alpine steppe

在祁连山高寒草原甘肃马鹿冬季牧场和春秋季牧场,分别设置6个牧压梯度样地,研究土壤水分和生物量的关系。结果表明,冬季牧场和春秋季牧场土壤水分与放牧率均显著负相关(P<0.01),冬季牧场地上生物量和春秋季牧场地下生物量分别与土壤水分显著正相关(P<0.05)。结构方程模型表明,冬季牧场土壤水分对地上生物量作用最大,通过地上生物量对根冠比产生极显著间接作用;春秋季牧场地下生物量与根冠比显著相关,土壤水分通过地下生物量对根冠比产生间接作用。

An experiment was performed in winter and spring-autumn pastures of Gansu wapiti in Gansu Province,Sunan Yugu National Autonomous County,using six different grazing gradient plots.The wild fixed-point sampling observation method was used to study the interaction of grassland soil moisture with biomass under the influence of different grazing gradients.The results showed that there were significant negative correlations between soil moisture and grazing rate in both winter and spring-autumn pastures in the Qilian Mountains (P < 0.01).There was a significant positive correlation between winter pasture biomass and soil moisture (P < 0.05).There was a significant positive correlation (P < 0.01) between underground biomass and soil moisture in spring-autumn pasture.A structural model showed that soil moisture of winter pastures had the greatest effect on aboveground biomass,and that soil moisture had a significant indirect effect on the root and shoot ratio through aboveground biomass.The underground biomass of spring-autumn pasture had the greatest effect on the root and shoot ratio,and soil moisture had a significant indirect effect on root and shoot ratio through underground biomass.