Blending loss-control and normal urea maximizes nitrogen utilization of summer maize by mitigating ammonia volatilization and nitrate leaching

Aims Loss-control urea has been shown to be an effective strategy for increasing crop yield and N use efficiency (NUE) in maize production. However, it remains unclear whether loss-control urea blended with normal urea can reduce the environmental impact while maximizing N utilization. Methods Field experiments were conducted on summer maize fields in two regions of the North China Plain (Wenxian and Yuanyang) to assess N loss through NH 3 volatilization and NO 3 − - N leaching. Six treatments were implemented: no N fertilizer (CK), normal urea (U1), farmers’ N practice (U2), and various blending ratios of loss-control and normal urea (CU1(7:3), CU2(5:5), CU3(3:7)). Results Daily NH 3 fluxes peaked within 1 week after sowing, with most NH 3 volatilization (> 90%) occurring in the first month after sowing. Compared with U, CU significantly reduced NH 3 volatilization in Wenxian and Yuanyang. Application of CU reduced NO 3 − - N residues in deeper soil layers by increasing NO 3 − - N accumulation within the 40 cm soil layer. Among these, CU2 increased grain yield and NUE compared to U treatments. Comparatively, CU treatments contributed more to maize yield and had less effect on NH 3 volatilization and deep soil NO 3 − - N residues in the structural equation model. Conclusions Our results highlighted that loss-control urea and normal urea blend ratio of 5:5 (CU2) achieved a win–win scenario in terms of crop productivity and ecosystem services and was recommended as the best N fertilizer application strategy for the sustainable production of dryland maize in the North China Plain.