Optimal planting density and proper fertilization method are important factors to improve maize yield and nutrient utilization. A two-year (2016 and 2017) field experiment was conducted with three plant densities (6.0, 7.5 and 9.0 plants m^–2) and three fertilization modes (no fertilizer, 0F; one-off application of slow-released fertilizer, SF; twice application of conventional fertilizer, CF). Results indicated that the grain yields and N, P and K use efficiencies under SF with the optimal planting density (7.5 plants m^–2) were the highest among all the treatments in 2016 and 2017. Compared with CF, SF could increase post-silking dry matter accumulation and promote N, P and K uptake at pre- and post-silking stages; this treatment increased grain N, P and K concentrations and resulted in high N, P and K use efficiencies. Nutrient (N, P and K) absorption efficiencies and partial productivity, and nutrient (N and P) recovery efficiency in SF treatment were significantly higher than those in CF treatments under the planting density of 7.5 plants m^–2. Under both SF and CF conditions, the grain yield, total N accumulation and nutrient use efficiencies initially increased, peaked at planting density of 7.5 plants m^–2, and then decreased with increasing plant density. Based on the yield and nutrient use efficiency in two years, plant density of 7.5 plants m^–2 with SF can improve both the grain yield and N, P and K use efficiency of spring maize in Jiangsu Province, China.

最佳种植密度和适当的施肥方法是提高玉米产量和养分利用率的重要因素。进行了为期两年（2016年和2017年）的田间试验，采用了三种植物密度（6.0、7.5和9.0植株m ^-2）和三种施肥模式（无肥料，0F；一次性施用缓释肥料，SF；以及一次性施肥）。两次施用常规肥料（CF）。结果表明，在最佳种植密度（7.5植株m ^–2）下，SF下的谷物产量以及N，P和K的利用效率）是2016年和2017年所有处理中最高的。与CF相比，SF可以增加生长期和后期的氮素，磷和钾吸收。这种处理增加了谷物中氮，磷和钾的浓度，并提高了氮，磷和钾的利用效率。在种植密度为7.5 m ^-2的条件下，SF处理的养分（N，P和K）吸收效率和部分生产力以及养分（N和P）的回收效率显着高于CF处理。在SF和CF两种条件下，谷物产量，总氮积累和养分利用效率最初都提高了，在种植密度为7.5 m ^–2时达到峰值。，然后随着植物密度的增加而降低。根据两年的产量和养分利用效率，含SF的7.5株m ^-2的植物密度可以提高江苏省春玉米的籽粒产量以及N，P和K的利用效率。