Optimizing nitrogen application frequency to enhance the post-flowering matter accumulation, yield and water/nitrogen...

Maize yield stability is crucial for China's national food security. Conventional irrigation and nitrogen application methods have problems like low yield, inefficiency and environmental pollution. Optimizing water/fertilizer management is therefore imperative. This study reports on a field experiment conducted in Tongliao, Inner Mongolia (2020-2021) that used 'Dika 159' maize grown at a density of 9.0 × 10⁴ plants ha^-1. Five nitrogen application frequencies were set up, 0 (F0), 2 (F2), 4 (F3), 6 (F4), 8 (F5) with drip irrigation, in addition to farmers' one-time basal and flood irrigation as the control (F1).

Compared that of F1, the leaf area index of F4 increased by 5.05% at the VT (silk emergence) stage and by 73.01% at the R6 (maturity) stage, and the maximum leaf area duration appeared at the VT-R3 (silk emergence-milk ripening) stage. The frequency of nitrogen application mainly affected the post-anthesis photosynthetic rate of maize. F4 and F1 did not differ significantly in their pre-anthesis matter accumulation, but F4's post-anthesis matter accumulation was significantly higher, the maximum dry matter accumulation rate of F4 being 94.44% higher than that of F1. The six-time nitrogen application resulted in the optimum yield (15.82-16.06 t ha^-1) and physiological nitrogen-use efficiency (PNUE; 7.87-7.44 kg kg^-1), and its water-use efficiency (WUE) reached 2.10-2.14 kg m^-3, raising the yield by 65.75-69.84%, enhancing the WUE by 62.12-62.79% and improving the PNUE by 29.23-40.11%.

A greater frequency of nitrogen application (six times) can prolong the functional period of maize leaves, slow leaf senescence, enhancing the post-anthesis photosynthetic capacity of maize to bolster its post-anthesis matter accumulation and kernel weight, improving the yield and water/fertilizer utilization rate. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.