Optimization of shallow buried drip irrigation and nitrogen management for spring maize in the sandy land of Northwest China

The limiting of water resources along with poor soil water and fertilizer retention capacity of sandy land in Northwest China resulted in low crop water and fertilizer utilization efficiency under traditional irrigation. Optimization of shallow buried drip irrigation (SBDI) and fertilizer application for the sandy land is significantly important in improving the efficiency of the local agriculture production. In this study, a two-year (2022 and 2023) field experiment was conducted to explore the effects of irrigation quota and nitrogen application amount on spring maize growth, grain yield, actual water consumption (ET), water use efficiency (WUE) and nitrogen fertilizer partial productivity (PFPN) under three irrigation quota (375, 300 and 225 m³ hm^–2, designated as T1, T2 and T3, respectively) and nitrogen application amounts (600, 450 and 300 kg hm^–2, designated as N1, N2 and N3, respectively). The results showed that:1) The plant height of T1N1was significantly higher compared to T3-level treatments (P < 0.05), and stem diameter and LAI also showed significant advantages over T1N3. There was no significant difference in aboveground dry matter mass between T1N1 and T1N2, but both of them were significantly higher than T1N3. 2) Irrigation quota and nitrogen application amount had a significant impact on the yield components and yield of spring maize. Yield analysis revealed that T1 increased by 19.74 % compared to T3, while N1 increased by 12.52 % compared to N3. The highest yield (T1N2) reached 14,487.91 kg hm⁻² (2022) and 14,522.34 kg hm⁻² (2023). The irrigation quota, nitrogen application amount, and the interaction between them had a highly significant impact on ET, WUE, and PFPN. The ET increased with the increase of irrigation quota and nitrogen application amount, peaking at 583.1 mm (2022) and 467.3 mm (2023). The WUE peaked at 25.17 kg mm⁻¹ hm⁻² (T2N1) in 2022 and 33.35 kg mm⁻¹ hm⁻² (T2N2) in 2023, respectively, while the PFPN decreased with the increase of nitrogen application, maxing at 42.23 kg kg⁻¹ (T2N3, 2022) and 41.17 kg kg⁻¹ (T1N3, 2023). 3) Based on binary quadratic regression analysis, optimal irrigation quota, nitrogen application amounts were determined to be 314.78–342.98 m³ hm^–2 (4–5 times in high rain years and 6–7 times in normal rain years) and 481.98–498.00 kg hm⁻², respectively, to achieve 95 % of maximum yield potential under SBDI. This study provides a guideline for appropriate water and fertilizer management for sustainable spring maize production in the sandy land of Northwest China.