亚热带地区土壤硝酸盐异化还原成铵速率的空间差异和驱动因素

土壤硝酸盐异化还原成铵(DNRA)是生态系统土壤氮转化的重要途径，理清环境因素对土壤DNRA速率的影响意义重大。本研究通过收集246项试验观测值采用整合分析方法(Meta-analysis)研究了亚热带地区不同生态系统中DNRA速率的变化范围及其影响因素。结果表明：纬度对亚热带土壤DNRA速率无显著影响；土壤p H、全氮(TN)、SOC/NO₃^–-N、Fe(Ⅱ)、阳离子交换量(CEC)、易氧化有机碳(EOC)、有效磷(AP)、黏粒含量和年平均气温(MAT)的增加均会促进DNRA速率；年平均降水量(MAP)和土壤NH₄⁺-N含量的增加会抑制土壤DNRA速率。此外，环境因子对DNRA速率的影响随生态系统的不同表现出较大差异。结构方程模型分析结果显示，SOC/NO₃^–-N是DNRA主要驱动因素，p H、NH₄⁺-N、MAP和MAT对土壤DNRA也有较大影响。

Spatial Difference and Driving Factors of Soil Nitrate Dissimilation to Ammoniumin Subtropical Area

The reduction of soil dissimilatory nitrate to ammonium (DNRA) is a vital pathway for soil nitrogen transformation in ecosystems. Clarifying the impact of environmental factors on soil DNRA rates is urgent. In this study, 235 experimental observations are collected to investigate the variation range of DNRA rates and their influencing factors in different ecosystems in the subtropical region using meta-analysis. The results showed that latitude had no significant effect on subtropical soil DNRA rates. The increase in mean annual temperature (MAT), pH, total nitrogen (TN), C/NO3--N, Fe(II), cation exchange capacity (CEC), easily oxidizable organic carbon (EOC), available phosphorus (AP), and soil clay content promoted DNRA rates. However, the increase of mean annual precipitation (MAP) and soil NH4+-N content inhibited soil DNRA. In addition, the effects of environmental factors on the DNRA rate were complicated in different ecosystems. Structural equation model analysis revealed that C/NO3--N was the main driving factor of DNRA, and MAP, MAT, pH, and NH4+-N also had a significant influence on soil DNRA. This study provided a theoretical reference for technical research on improving nitrogen utilization in subtropical soils.