Effects of nitrogen addition on activities of soil nitrogen acquisition enzymes：A meta-analysis

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2018-01, Vol.252, p.126-131
• Main Authors: Chen, Hao, Li, Dejun, Zhao, Jie, Xiao, Kongcao, Wang, Kelin
• Format: Article
• Language: English
• Subjects: Aminopeptidase; Biological activity; Depolymerization; Deposition; Ecosystems; Environmental changes; Enzymes; Flowers & plants; Glycine; Leucine; Meta-analysis; Microbial activity; Microorganisms; Mineralization; N deposition; N mineralization; N-Acetylglucosaminidase; N-acquisition enzymes; Nitrogen; Plant cells; Polymerization; Protein depolymerization; Soil fertility; Soils; Studies; Urease
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2017.09.032

[Display omitted] •A meta-analysis was used to address effects of N addition on N-acquisition enzyme.•N addition increased activities of N-acetylglucosaminidase and urease.•N addition had negative or negligible effects on protein-deploymerization enzymes.•N addition has minor effects on soil N mineralization by changing microbial activity. It has been suggested that elevated nitrogen (N) deposition may increase soil N mineralization in N-limited ecosystems, but the underlying mechanisms have been not adequately explored. Soil N-acquisition enzymes play important roles on organic N mineralization. Thus, their responses to N deposition will be crucial for explaining the above phenomenon. Here, we conducted a meta-analysis from 64 studies to synthesize the responses of soil N-acquisition enzyme activities to N addition. Results showed that N addition significantly increased activities of N-acetylglucosaminidase and urease by 5.5% and 11.6%, respectively. However, N addition had negative or negligible effects on activities of protein-depolymerization enzymes, with no response for non-specific protease and leucine aminopeptidase but a significant decrease of 33.0% for glycine aminopeptidase. Because protein comprises more than 60% of the N in plant and microbial cells, and the protein depolymerization is an important rate-limiting step of organic N mineralization, the suppressed protein depolymerization indicates either that the changes to microbial activity may be not a dominant mechanism for the increased N mineralization in N-limited ecosystems with N addition, or that the increased N mineralization may be overvalued in the previous studies.