三江源高寒草甸土壤化学计量特征及酶活性对不同退化程度的响应

Soil stoichiometries and enzyme activities are important indices for plant growth and nutrient cycles. In order to explore the changes and interaction between soil stoichiometries and enzyme activities during the deg⁃ radation of the alpine meadow in the headwaters of Three Rivers,the field sampling and laboratory analysis was used in this study. The effects of different degradation degrees（natural vegetation,light degradation,moderate degradation and severe degradation） on the soil organic carbon （SOC）,total carbon （TC）,total nitrogen （TN）,total phosphorus（TP）,total potassium（TK）,pH,soil stoichiometries and enzyme activities and their interactions were analyzed. The results show that：（1）With the aggravation of degradation degree,SOC and TN contents in different soil layers showed an overall decreasing trend,while TK contents showed an increasing trend,and there was no significant difference among soil layers. TP content showed the highest values in light degradation areas,with all the values greater than 0. 7 g·kg-1. The pH value did not change significantly with the degradation degree. （2）The stoichiometric ratio of C,N,P and K of soil decreased with degradation degree,and the ratios of carbon to nitrogen were relatively stable. （3）The activities of β-1,4-xylosidase（BX）,β-nacetylglucosaminidase（NAG）,acid phosphatase（AP）,β-fiber diglycosidase（BCE）and β-glucosidase（BG）in different soil layers were higher in the light degradation（P<0. 05）than other levels of degradation. （4）SOC,TN,TP content and stoichiometric ratios were positively correlated with the activities of AP,BG,BCE,BX and NAG,while pH was negatively correlated with the activities of five enzymes（P<0. 05）. In conclusion,the degradation of alpine meadow is closely related to soil stoichiometries and soil enzyme activities,and soil stoi⁃ chiometries and enzyme activities showed great differences among different degradation stages. Our results pro⁃ vide a scientific basis for the treatment and restoration of alpine meadow at different degradation stages. Copyright © 2023 Institute of Microbiology, CAS. All rights reserved.