Nitrogen Addition Effects on Wetland Soils Depend on Environmental Factors and Nitrogen Addition Methods: A Meta-Analysis

Identifying the effects of nitrogen (N) addition under key environmental factors and N addition methods can aid in understanding the paradigm of N addition in wetland ecosystems. In this study, we conducted a meta-analysis of 30 field studies of wetland ecosystems and selected 14 indicators. We found that the changes in soil TN and SOC contributed significantly to the changes in microbial community structure under N additions. The environmental factors and N addition methods altered the direction or size of N addition effects on wetland soil properties, microbial diversity and key C and N cycling genes. N-limited conditions and climate conditions determined the N addition effect direction on SOC, and saline-alkali conditions determined the N addition effect direction on microbial diversity and AOB abundance. Environmental heterogeneity and N addition methods determine the response of wetland soil to nitrogen application. Therefore, it is crucial to study the effects of environmental factors and N addition methods on the N deposition of wetland soils.

Automated summary

This study conducted a meta-analysis of 30 field studies of wetland ecosystems to investigate the effects of nitrogen addition on wetland soil properties. The results showed that changes in soil total nitrogen and soil organic carbon significantly influenced the microbial community structure. Additionally, the environmental factors and nitrogen addition methods played a role in altering the effects of nitrogen addition on wetland soil properties, microbial diversity, and key carbon and nitrogen cycling genes.