Abstract：
Quantification of nitrogen (N) cycling genes contributes to our best understanding of N transformation processes. The application of organic amendment (OA) is widely recognized as an effective measure to improve N management and soil fertility in various ecosystems. However, our understanding of N-cycling gene abundances in response to OA application remains deficient. We performed a meta-analysis embracing 124 sets of observation data to study the impact of OA application on the main N-cycling gene abundances, including nifH, amoA, nirS, nirK and nosZ. We found that the significantly positive response of N-cycling gene abundances to OA application was attributed to the rotation cropping system (by 6.45 %-104.20 %) in the field experiment (by 19.43 %-52.56 %), OA application alone (by 8.29 %-111.70 %) especially manure addition (by 33.43 %-98.70 %), application dose of OAs within 10-20 t ha-1 (by 45.33 %-381.90 %), fertilization duration <5 years (by 43.69 %-112.63 %), C/N of OA <25 (by 37.87 %-160.90 %), SOC lower than 1.2 % (by 41.44 %-157.89 %) and application to alkaline soil (by 32.24 %-134.40 %). Moreover, soil organic carbon (SOC) and pH were the most essential regulators associated with N-cycling gene abundances with OA application. Identification of key driving factors of the abundance of N-cycling functional genes will help remedy strategies for managing OAs in ecosystems.
摘要：
氮（N）循环基因的定量有助于我们对N转化过程的最佳理解。有机改良剂（OA）的应用被广泛认为是改善各种生态系统中氮素管理和土壤肥力的有效措施。然而,我们对响应OA应用的N循环基因丰度的理解仍然不足。我们进行了包含124组观察数据的荟萃分析，以研究OA应用对主要N循环基因丰度的影响，包括nifH,amoA,nirs,NirK和NosZ.我们发现，N循环基因丰度对OA施用的显着阳性反应归因于田间试验中的轮作系统（6.45％-104.20％）（19.43％-52.56％），单独施用OA（8.29%-111.70%），特别是添加粪肥（33.43%-98.70%），10-20tha-1范围内的OAs施用剂量(45.33%-381.90%)，施肥持续时间<5年(43.69%-112.63%)，OA的C/N<25（37.87%-160.90%），SOC低于1.2%(由41.44%-157.89%)和应用于碱性土壤(由32.24%-134.40%)。此外，土壤有机碳（SOC）和pH是与OA应用中N循环基因丰度相关的最重要调节因子。确定氮循环功能基因丰富的关键驱动因素将有助于纠正生态系统中OAs管理策略。
