Contents and eco-stoichiometric characteristics of soil carbon,nitrogen,and phosphorus in alpine grass-lands with different degradation degrees
To clarify the contents and ecological stoichiometric characteristics of soil carbon(C),nitrogen(N),and phosphorus(P)in alpine grasslands under different degradation degrees,we analyzed soil organic C(SOC),N,P,C∶N,C∶P and N∶P in undegraded(ND),lightly degraded(LD),moderately degraded(MD)and se-verely degraded(SD)alpine grasslands.The results showed that soil SOC,N,and P contents showed a decreasing trend with increasing degradation degree of grasslands.The average values of C∶N,C∶P,and N∶P were lower than the global level,all of which showed N-shaped changes with increasing degradation degree.Soil SOC,N,C∶P,N∶P,and N∶P were negatively correlated with soil pH and bulk density(P＜0.05).Soil SOC,N,P,C∶P,and N∶P were positively correlated with soil water content(P＜0.05).Soil P was not significantly correla-ted with soil bulk density(P＞0.05).Soil C∶N was positively correlated with soil pH and bulk density(P＜0.01),and negatively correlated with soil water content(P＜0.01).Results of structural equation modeling indicated that grassland degradation directly affected soil physicochemical properties and thus soil SOC,N,and P content and their eco-stoichiometric ratio.In summary,grassland degradation changed soil microenvironment by reducing soil water content and increasing pH and bulk density,resulting in decreases in the contents of SOC,N,and P.
alpine grasslanddegradationeco-stoichiometric ratiovertical distribution
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