Deep Straw Incorporation With Supplemental Fertilization Improves Subsoil Quality and Maize Productivity

ABSTRACT

Deep straw incorporation is widely advocated for enhancing crop yields and improving agroecosystem functions and services. However, how this practice interacts with different fertilization strategies synergistically to influence soil quality and maize productivity remains unclear. A two‐year field experiment in Northeast China evaluated deep maize straw incorporation with various fertilization regimes on soil fertility and maize yield. Four treatments were compared: deep straw incorporation without nitrogen addition (DSI), DSI with low nitrogen addition (DSI‐LN), DSI with high nitrogen addition (DSI‐HN), and DSI with microbial fertilizer addition (DSI‐MF). Compared with DSI, all fertilization treatments increased subsoil organic carbon stocks. Notably, DSI‐HN and DSI‐MF significantly enhanced subsoil quality indices. These improvements in subsoil quality were accompanied by increases in maize yield, with yield gains of 5%–8% across fertilization treatments. Moreover, subsoil quality indices were positively correlated with maize yield, indicating that enhanced subsoil quality contributed to high grain production. Collectively, deep straw incorporation with supplemental fertilization improved both subsoil quality and maize yield, underscoring the importance of targeted subsoil management for improving subsoil fertility and plow layer structure. Extended field experiments are critical to further assess the persistence and cumulative benefits of these practices for sustainable agricultural intensification.