Impact of fertilization schemes with different ratios of urea to controlled release nitrogen fertilizer on environmental sustainability, nitrogen use efficiency and economic benefit of rice production: A study case from Southwest China

Abstract

Controlled release nitrogen fertilizers (CRNF) possess good nutrient release performance and application prospects. Under the dual pressures of food security and environmental protection, whether substitution of urea using CRNF could improve environmental sustainability of rice production relative to the utilization of single urea, as well as ensure the rice yield and farmers’ income, should be deeply investigated to promote wide application of this kind of fertilizer. Based on one-year field experiment and field surveys, four fertilization schemes with different ratios of urea to CRNF were set up, i.e., control (CK), local recommended application amount urea (N1), 100% CRNF (N2), and the combined application of 60% CRNF and 40% urea (N3). Adjusted emergy accounting (EMA), which considers emissions’ impacts, and nitrogen use efficiency (NUE) as well as economic indicators were applied to the comparison of environmental sustainability, agronomic indicator and economic benefit of different schemes respectively. The results showed that (1) CRNF utilization raises environment sustainability by 2.82–4.61%; (2) CRNF utilization improves nitrogen use efficiency by 30.65–43.96%; (3) CRNF utilization enhances economic benefit by 5.21–11.44%. Generally, N3 has the best system coordination degree among the three fertilization schemes. Finally, the study suggested popularizing the scheme N3 in this region through adopting appropriate financial and policy support. Meantime, technological innovation, and regulatory supports are needed to accelerate the development of the CRNF industry.