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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (2): 521-528.doi: 10.13287/j.1001-9332.202102.038

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Enzyme stoichiometry evidence revealed that five years nitrogen addition exacerbated the carbon and phosphorus limitation of soil microorganisms in a Phyllostachys pubescens forest

ZENG Quan-xin1,2, ZHANG Qiu-fang1,2, LIN Kai-miao2,3, ZHOU Jia-cong1,2, YUAN Xiao-cun1,2, MEI Kong-can1,2, WU Yue1,2, CUI Ju-yan1,2, XU Jian-guo2,3, CHEN Yueh-min1,2*   

  1. 1School of Geographical Science, Fujian Normal University, Fuzhou 350007, China;
    2Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou 350007, China;
    3Daiyun Mountain National Nature Reserve Administration Bureau, Quanzhou 362500, Fujian, China
  • Received:2020-06-22 Accepted:2020-11-04 Online:2021-02-15 Published:2021-08-15
  • Contact: *E-mail: ymchen@fjnu.edu.cn
  • Supported by:
    National Natural Science Foundation of China (31670620) and the Natural Science Foundation of Fujian (2019J05163)

Abstract: The activity and stoichiometry of soil extracellular enzyme can provide a good indication for changes in soil nutrient availability and microbial demands for nutrients. However, it remains unclear how would nitrogen (N) deposition affect nutrient limitation of microbes in subtropical forest soils. We conducted a 5 years N addition experiment in a subtropical Phyllostachys pubescens forest. The soil nutrients and enzyme activities associated with carbon (C), N, and phosphorus (P) cycles were measured. We also examined the nutrient distribution of microorganisms using enzyme stoichiometry and vector analysis. The results showed that N addition significantly decreased the contents of soil soluble organic C and available P and increased that of available N. Furthermore, N addition significantly decreased β-N-acetyl-glucosaminidase (NAG) activity and NAG/ microbial biomass carbon (MBC), and increased acid phosphatase (ACP) and ACP/MBC. The low and moderate N addition levels significantly increased enzyme C/P, vector length, and vector angle, but significantly decreased enzyme N/P. Results of redundancy analysis showed that the change in soil enzyme activity and enzymatic stoichiometry were mainly driven by soil available P content under N addition. In summary, N addition altered the microbial nutrient acquisition strategy, which increased nutrient allocation to P-acquiring enzyme production but reduced that to N-acquiring enzyme production. Moreover, N addition exacerbated the C and P limitation of soil microorganisms. Appropriate amount of P fertilizer could be applied to improve soil fertility of subtropical P. pubescens forest in the future.

Key words: nitrogen addition, enzyme activity, enzyme stoichiometry, nutrient restriction