关键词: 羊草草地, 土壤环境因素, 活根生物量, 灰色分析, 系统耦合

Abstract: Using the gray system analysis method,a study was conducted in Qianguo county,Jilin Province,on the characteristics of several Leymus chinensis communities and their soil environment,as well as the relationship between the two.The result shows:the living root biomass of three communities tended to decrease as the roots penetrated deeper into the earth layer where soil nutrients reduced with the descending depth the roots reached.The nutrients kept a big gray connection to the living root biomass,but remained the same as it in the variation tendency,being an advantage factor.The index of soil alkalinity rose with the depth of the soil layer,but they kept only a slight gray connection to the living root biomass.The variation tendency of the soil alkalinity index was contrary to that of the living root biomass,as the former being a restricted factor.Coupling relation analysis indicated that coupling intensity was the strongest and the coupling relationship the best between the L.chinensis communities and the soil where they grow.The L.chenensis communities yield superior forages and boast high potential productivity.However,in deteriorated grassland caused by excessive grazing,the coupling intensity between vegetation and soil is minimum,the system runs counter,and the communities are degenerating gradually.

Key words: Leymus Chinensis Grassland, Soil environmental factors, Living root biomass, Grey analysis, System coupling