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Chinese Journal of Applied Ecology ›› 2019, Vol. 30 ›› Issue (9): 3039-3045.doi: 10.13287/j.1001-9332.201909.004

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Responses of stoichiometric characteristics of rhizosphere soil to the degradation of alpine meadow.

MA Yuan, LI Lin-zhi, ZHANG De-gang*, XIAO Hai-long, CHEN Jian-gang   

  1. College of Pratacultural Science/Ministry of Education Key Laboratory of Grassland Ecosystem, Gansu Agricultural University, Lanzhou 730070, China
  • Received:2019-04-26 Online:2019-09-15 Published:2019-09-15
  • Contact: * E-mail: zhangdg@gsau.edu.cn
  • Supported by:
    This work was supported by the National Key R&D Program of China (2016YFC0501902) and the Universities Research Project of Gansu Provincial Education Department (2018A-038).

Abstract: This study aimed to understand the stoichiometric characteristics of carbon (C), nitrogen (N) and phosphorus (P) and soil nutrients in rhizosphere and non-rhizosphere soils and to obtain information on the status of soil and microbial nutrient limitation in degraded alpine meadow. We collected soil samples from rhizosphere (0-2 mm) of dominant plant species and non-rhizosphere (0-10 cm) of the alpine meadow with four different degraded degrees in the Qilian Mountains. We measured the concentration of C, N and P and extractable C, N, P (Ext-C, Ext-N, Ext-P), the activity and proportion of extracellular enzymes (β-1, 4-glucosidase, β-1, 4-N-acetylglucosaminidase, leucine aminopeptidase and acid phosphatase) involved in C, N, P cycles, as well as soil microbial biomass (MBC, MBN, MBP). The results showed that nutrient concentrations in the rhizosphere of dominant species was higher than that in non-rhizosphere. With the increases of degradation degree, soil C:N:P changed significantly, and resulted in a serious imbalance of C:N and severe N limitation. In the degraded alpine meadows, the ratio of log-transformed rhizosphere C-, N- and P-extracellular enzymes deviated from the 1:1:1 of global ecosystem, indicating that nutrient supply was mainly restricted by N and followed by P. The contents of soil total nutrients in degraded alpine meadow was relatively high, but the contents of soil available nutrients were low, which would hinder plant growth.