Optimizing nutrient inputs by balancing spring wheat yield and environmental effects in the Hetao Irrigation District...

The Hetao Irrigation District is the primary spring wheat production region in China. However, overuse and unscientific use of chemical fertilizer have resulted in low nutrient use efficiency and potential risks to the environment. Balanced fertilization (BF), a 29.9-36.4% N fertilizer and 40% P fertilizer, was reduced, while a 72 kg K₂O ha^-1 K fertilizer was supplied and designed to resolve problems encountered during the field trial from 2019 to 2021. The results showed that the grain yield did not decrease significantly in the BF treatments compared in the local farmer practice (FP) treatment. The nitrogen fertilizer partial productivity (PFP_N) and agronomic nitrogen efficiency (NAE_N) increased 42.95-52.88% and 44.06-49.24% with BF compared to with the FP, respectively. Moreover, the BF treatments reduced nitrate leaching in the 0-100 cm soil layer and reduced the N surplus (N_sur) to approximately 160 kg N per hectare per year, dramatically reducing the environmental risk. The yield maintenance and nitrogen use efficiency increases were attributed to the lower nitrogen concentrations in the seedlings and the higher apparent N translocation efficiency (TR) from the stems and sheaths after anthesis in the BF treatments than in the FP treatments. Considering the yield, nutrient use efficiency, and environmental and economic benefits comprehensively, the BF1 treatment was considered the optimal fertilization scheme for Hetao spring wheat production.