Effects of biochar application on soil nitrogen transformation, microbial functional genes, enzyme activity, and plant nitrogen uptake: A meta‐analysis of field studies

Biochar application can influence soil nitrogen (N) cycle through biological and abiotic processes. However, studies on comprehensive examination of the effects biochar microbially mediated N-cycling processes (N mineralization, nitrification, denitrification, fixation) N fate (i.e., plant uptake, N2O emission, leaching) are warranted. Therefore, aim this study was to examine transformation, microbial functional gene abundance, enzyme activity, uptake. To achieve objective study, a meta-analysis involving 131 peer-reviewed field experiments conducted. Results showed that significantly enhanced content, N2 fixation, uptake by 5.3%, 3.7%, 15.3%, 48.5%, 14.7%, 18.3%, respectively, but reduced emissions leaching 14.9% 10.9%, respectively. also increased abundance denitrifying/nitrifying genes (amoA, narG, nirS/nirK+S, nosZ), proportion fixation bacteria, N-acetyl-glucosaminidase activity 18.6%–87.6%. Soil content positively correlated with AOA-amoA emission relative (e.g., amoA, nirS/nirK) involved in production. Furthermore, long-term tended increase AOB-amoA nirK+S especially leaching. Overall, findings indicated accelerated under conditions, thereby enhancing availability productivity. may losses. future should be conducted effect underlying mechanisms.