Unveiling the environmental and socioeconomic benefits of precision nitrogen management for paddy fields in subtropical China

Precision fertilizer management has been well proved to allow farmers to synchronize nitrogen (N) fertilizer input with crop demand to improve grain yield and N use efficiency (NUE). However, the potential environ-mental benefits of precision fertilizer management have been less evaluated and appreciated. In this study, we selected five most commonly used optimized N fertilizer management strategies (OPM), which are Flav-basal strategy, site-specific N management strategy, optimization algorithm, N nutrient index-based fertilizer man-agement strategy and normalized difference red-edge based fertilizer management strategy, and compared with farmer practices (FP) in yield, resource inputs (i.e., mineral, land, labor, etc.), energy use, NUE, greenhouse gases emissions (GHGs), NH3, NOX and SO2 emissions, N leaching and runoff, and economic returns in Chinese southeast paddy fields. Our results showed that the OPM strategies could increase grain yield by 13.5 % at most, NUE by 3-10 % and harvest index by 1-7 kg kg-1 compared to the FP with the optimal total N application was approximately 270-290 kg N ha-1. Agronomic benefits generally increased by $ 145-620 ha-1, with the shoot biomass increasing by $ 90-185 ha-1 of adopting through OPM for rice production. Additional benefits from the mitigation of GHGs emissions could significantly increase the environmental benefits of precision N manage-ment. Altogether, the environmental benefits of OPM are considerable, and they are likely to be adopted by farmers if new incentives from the government.

Automated summary

Precision fertilizer management can improve grain yield and nitrogen use efficiency, and also has potential environmental benefits, such as reducing greenhouse gas emissions and nitrogen leaching.