Adaptive nitrogen inputs sustain soil water balance and improve maize productivity with varied precipitation conditions on semiarid agro-ecosystem

Background and Aims: Maize productivity in semi-arid regions of Loess Plateau is increasingly at risk because of sparse and uneven distribution of rainfall, and is also restricted by unscientific (excessive or insufficient) fertilization management strategy. Formulating a high-efficient fertilization scheme based on rainfall variability and soil moisture before sowing can guarantee sustainability of water use and maize production. Methods: A 4-year (2016−2019) field experiment was conducted to reveal the effects of fertilizer with five nitrogen rates (0, 75−90, 150−180, 270 and 360 kg ha −1 , represents as N 0 , N 75-90 , N 150-180 , N 270 , N 360 , respectively) under two variable rainfall patterns (one was rainy at pre-anthesis in 2017 and 2019; another was dry at pre-anthesis) on soil water storage (SWS), maize yield, water use efficiency (WUE) and water balance. Results: The results showed that dry at pre-anthesis significantly reduced biomass accumulation and kernel number per plant. N inputs increased aboveground dry matter and WUE for dry matter pre-anthesis (WUEd). However, soil water storage before sowing (SWSs) decreased from 440 mm in 2016 to 378.3~390.1 mm in 2019, and the increase of fertilization increased the imbalance of soil moisture. The grain yield and WUE for yield (WUEg) of applying N fertilizer was 9.1–76.7% and 14.9–80.8% higher than that of non-N treatments, respectively. In the case of being rainy before anthesis there occurred the highest grain yield and WUE for grain yield (WUEg) in N 270 , whereas spring maize performed better in N 150-180 during dry years before anthesis. The average NRE and NPFP decreased with increases of N application, and both of them under N 150-180 treatment could reach 92.9% and 66.1% of the maximum values, respectively. The grain yield showed a positive correlation with SWSs. Conclusions: We clarified that: 1) N applications improved WUEg by increasing deeper soil water absorption and WUEd before anthesis; 2) reducing basal fertilizers and adjusting N fertilizer inputs based on rainfall before anthesis could enhance maize yield and maintain water balance in the Loess Plateau.