Dense planting and nitrogen fertilizer management improve drip-irrigated spring maize yield and nitrogen use efficiency in Northeast China

Farmers in China often use nitrogen (N) fertilizers to ensure adequate crop growth. However, inappropriate applications have increased the risk of environmental pollution, lowered maize yields, and reduced profits for farmers. Proper N fertilizer management is crucial for improving yield and nitrogen use efficiency (NUE). This study conducted a three-year experiment involving nine N treatments (0, 45, 90, 135, 180, 225, 270, 315, and 360 kg ha^–1) on a field under nitrogen fertilizer precision management (NFPM) in Northeast China. The results were compared with studies published within the past decade that analyzed yield and dry matter (DM) content under two management practices in Northeast China: conventional nitrogen fertilization management (CNFM) and water-saving fertilization management (WSFM). The findings reveal that maize yield increases with rising N application rates up to 270 kg ha^–1, after which yield decreases. The kernel number (KN) and kernel weight (KW) of maize grown under NFPM were 13.7 and 14.7% higher than those grown under WSFM, respectively. Furthermore, they surpassed crops grown under CNFM by 38.4 and 21.2%, respectively. The maximum total yield of the NFPM treatment was 41.8 and 78.8% higher than under WSFM and CNFM, respectively. In addition, compared with CNFM and WSFM, NFPM significantly increased NUE across the various N-level treatments. Optimizing nitrogen management can help farmers to achieve higher yields and promote sustainable agricultural development.