Work

Optimizing water and nitrogen management to reduce basal nitrogen inputs, improve nitrogen uptake and utilization efficiencies, and achieve high yields and low soil nitrate residue in wheat production

Year: 2025

Type: article

Abstract: Excessive basal nitrogen (N) inputs and improper water management limit both wheat yields and N use efficiency. Thus, a field experiment was conducted for two years to evaluate whether optimizing water and N management could reduce basal N inputs, improve N uptake and utilization efficiencies (NUpE and NUtE), and achieve high yields. A split-plot design was employed with water and N management as the main plots (conventional water and N management, CM; and drip fertigation, DF) and basal N rates as the sub-plots (150, 125, 100, 75, 50, 25, and 0 kg ha −1 , designated as B150, B125, B100, B75, B50, B25, and B0, respectively), while maintaining a fixed topdressing N rate of 150 kg ha −1 . The results showed that DF increased the average yield by 12.7–15.9% compared with CM due to improvements in N absorption, tillering ability, ear and grain numbers, leaf area index, and biomass production. More importantly, DF reduced the sensitivity of yield to the basal N rate. Halving the basal N rate from B150 to B75 reduced the yield by 4.1–4.3% under DF (P > 0.05), but the yield loss was 10.9–11.4% under CM (P < 0.05). Under DF, the increased grain weight compensated for the reduced grains m −2 , but under CM, the 17.3–17.8% reduction in grains m −2 was not fully offset by the increase of 8.4–9.9% in the grain weight. In addition, the increased NUpE and NUtE also contributed to relatively high yield at B75 under DF. Furthermore, the NO 3 − -N residue under DF was 7.9–9.8% lower at B75 than at B150. In conclusion, DF combined with a reduced basal N rate is effective for increasing wheat production, while decreasing soil nitrate residual levels to mitigate environmental impacts. • Drip fertigation enhances wheat N uptake and yield and decreases nitrate residue. • Reducing basal N rate increased N utilization efficiency but might hinder yield. • Adopting drip fertigation with reduced basal N is recommended for wheat production.

Source: Crop and Environment

DOI: 10.1016/j.crope.2025.11.001