INFLUENCE OF NITROGEN APPLICATION RATES ON NITROGEN ACQUISITION AND UTILIZATION EFFICIENCY OF MAIZE VARIETIES UNDER DRIP IRRIGATION SYSTEMS

Maize yield is significantly influenced by nitrogen fertilization, yet excessive application poses risks to human health and the environment.A sustainable approach to maintaining high maize production involves reducing nitrogen application and selecting genotypes excelling in nitrogen uptake, utilization, and remobilization.This study aimed to assess the impact of various maize genotypes and nitrogen levels on nitrogen use efficiency (NUE), nitrogen uptake efficiency (NUpE), and nitrogen utilization efficiency (NUtE) under drip irrigation.The research also sought to categorize these genotypes based on their NUE.The trials were conducted over two growing seasons, 2022 and 2023, at Anningqu Town, Urumqi City, Xinjiang Province, China.The study involved a combination of 17 maize genotypes and two nitrogen application rates, with lower (LN) and higher (HN) levels at 150 and 300 kg N ha -1 , respectively.Results indicated a decrease in total dry matter and total nitrogen uptake by 7.14% and 12.54% in 2022 and 2023, respectively.Conversely, the LN treatment enhanced NUtE, NUpE, and consequently NUE.Genotype, nitrogen application, and their interaction significantly influenced all traits (p < 0.05).NUE was strongly correlated with grain yield, total dry matter, and N uptake, and NUpE, but not with NUtE.The genotype Zhengdan958 demonstrated superior NUE under both LN and HN conditions.These findings indicate that certain maize genotypes can adapt to reduced nitrogen inputs, primarily through improved NUpE rather than NUtE.