Raw data

We synthesized 137 observations from 27 peer-reviewed publications and used meta-analysis to elucidate the responses of fine root decomposition rate to N addition and to identify the primary factors influencing these responses under different root characteristics.
N addition reduced fine root decomposition rate and mass loss by 8.52% and 6.24%, respectively. Specifically, fine roots with diameters ≤ 2 mm and first- and second-order roots exhibited negative responses to N addition. Overall, soil microbial biomass N and soil clay content were the main factors affecting the fine root decomposition rate in response to N addition. Within different root characteristics, soil microbial biomass N and soil N content were the primary factors regulating the response of fine roots ≤ 1 mm decomposition to N addition, while the N addition amount was the key factor of third to fifth-order root decomposition in response to N addition.
Our results suggested that the primary factors regulating the response of fine root decomposition rate to N addition varied across fine root characteristics. These differences in controlling factors highlighted the importance of incorporating fine roots characteristics into ecosystem models to predict the responses of belowground carbon and nutrient release to future climate changes.

我们从27篇同行评审的出版物中综合了137项观测结果，并通过元分析阐明了细根分解速率对氮添加的响应，同时识别了不同根系特征下影响这些响应的主要因素。氮添加分别使细根分解速率和质量损失降低了8.52%和6.24%。具体而言，直径≤2 mm的细根以及一级和二级根对氮添加表现出负响应。总体而言，土壤微生物生物量氮（soil microbial biomass N）和土壤黏粒含量是影响细根分解速率对氮添加响应的主要因素。在不同根系特征下，土壤微生物生物量氮和土壤氮含量是调控直径≤1 mm细根分解对氮添加响应的主要因素，而氮添加量则是三至五级根分解对氮添加响应的关键因素。我们的结果表明，调控细根分解速率对氮添加响应的主要因素因细根特征而异。这些调控因素的差异凸显了将细根特征纳入生态系统模型的重要性，以预测地下碳和养分释放对未来气候变化的响应。