Vital roles of soil microbes in driving terrestrial nitrogen immobilization

作者：Zhaolei Li, Zhaoqi Zeng, Zhaopeng Song, Fuqiang Wang, Dashuan Tian, Wenhai Mi, Xin Huang, Jinsong Wang, Lei Song, Zhongkang Yang, Jun Wang, Haojie Feng, Lifen Jiang, Ye Chen, Yiqi Luo, Shuli Niu · 发表于：Global Change Biology · 年份：2021 · DOI：10.1111/gcb.15552 · 被引用次数：158 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Plant nutrient uptake and metabolism

Abstract Nitrogen immobilization usually leads to nitrogen retention in soil and, thus, influences soil nitrogen supply for plant growth. Understanding soil nitrogen immobilization is important for predicting soil nitrogen cycling under anthropogenic activities and climate changes. However, the global patterns and drivers of soil nitrogen immobilization remain unclear. We synthesized 1350 observations of gross soil nitrogen immobilization rate (NIR) from 97 articles to identify patterns and drivers of NIR. The global mean NIR was 8.77 ± 1.01 mg N kg −1 soil day −1 . It was 5.55 ± 0.41 mg N kg −1 soil day −1 in croplands, 15.74 ± 3.02 mg N kg −1 soil day −1 in wetlands, and 15.26 ± 2.98 mg N kg −1 soil day −1 in forests. The NIR increased with mean annual temperature, precipitation, soil moisture, soil organic carbon, total nitrogen, dissolved organic nitrogen, ammonium, nitrate, phosphorus, and microbial biomass carbon. But it decreased with soil pH. The results of structural equation models showed that soil microbial biomass carbon was a pivotal driver of NIR, because temperature, total soil nitrogen, and soil pH mostly indirectly influenced NIR via changing soil microbial biomass. Moreover, microbial biomass carbon accounted for most of the variations in NIR among all direct relationships. Furthermore, the efficiency of transforming the immobilized nitrogen to microbial biomass nitrogen was lower in croplands than in natural ecosystems (i.e., forests, grasslands, and wetlan...