@article{Xu2026, 
author = {Cong Xu and Ziqi Yang and Jing Wang and Roland Bol and Weijie Li and Cheng Ji and Jie Yuan and Lei Wang and Dong Liang and Hanshen Zhu and Jidong Wang and Yongchun Zhang and Yuchun Ai},
title = {Fertilizer-N recovery links to SOC stabilization and fractionation in straw-mulched soil: Insights from 15N-tracing and 13C natural abundance},
year = {2026},
journal = {Journal of Integrative Agriculture (JIA)},
volume = {25},
number = {9},
pages = {3868-3881},
keywords = {fertilizer-nitrogen fate, soil aggregate, soil organic carbon flow, 15N, 13C},
url = {https://www.sciopen.com/article/10.1016/j.jia.2025.12.046},
doi = {10.1016/j.jia.2025.12.046},
abstract = {While straw mulching has the potential to reduce fertilizer-nitrogen (N) losses in intensively managed cropland, how soil organic carbon (SOC) regulates this fate of fertilizer-N at soil aggregate or profile scales remains unresolved.  Here, micro-plots were nested within a four-year field experiment to assess fertilizer-N fates and their linkages with SOC fractions and stabilization processes via 15N-tracing and 13C natural abundance analyses. Three treatments were included: (ⅰ) conventional N application (FN), (ⅱ) reduced N application (RN), and (ⅲ) reduced N with straw mulching (RS). While RN reduced crop yields compared to FN, RS achieved comparable yields and 7.71% higher N recovery efficiency (P<0.05). The  δ13C fractionation between aggregates and bulk soil was significantly positively correlated with the fertilizer-N content in  the >2 mm and <0.053 mm fractions, indicating that N retention was coupled with SOC stabilization processes. Compared with RN, RS resulted  in a 2−3.4  times greater SOC conversion probability  into  the <0.053 mm fraction and a 1.4  times  higher aggregate-associated fertilizer-N content.  SOC fractions differentially regulated the profile distribution of fertilizer-N,  with nonlabile organic carbon (C) correlated positively, while dissolved organic C correlated negatively but increased plant N recovery. Compared with RN, RS increased the SOC stock by 24%, reduced NO3−-N accumulation by 37%, and immobilized 36% more N into the microbial biomass (P<0.05).  Our findings demonstrate that straw mulching increases N  recovery by mediating SOC fractionation, stabilization, and microbial N immobilization. These results provide new insights into SOC–N interactions that could aid in the development of optimal soil C and N management strategies.}
}