施氮量和种植密度对洞庭湖区夏玉米产量及氮素利用的影响

Effects of nitrogen rate and planting density on the yield formation and the nitrogen fertilizer utilization in summer maize in Dongting Lake area

为完善洞庭湖区机收夏玉米配套高产高效栽培技术,以2个宜机收玉米品种(郑单958、湘农玉27号)为材料,于2017—2018年在湖南桃源县开展大田试验,研究施氮量(150、225、300 kg/hm^2)与种植密度(60 000、75 000、90 000株/hm^2)对夏玉米产量形成和氮素利用的影响。结果表明:夏玉米全生育期随施氮量增加延长2～4 d,适当早播可以缩短夏玉米全生育期;施氮量对夏玉米产量无显著性影响,种植密度、品种和种植密度互作、种植密度和施氮量互作对产量影响显著,施氮量宜随种植密度增大适当减少;郑单958在90 000株/hm^2与150 kg/hm^2施氮量条件下产量最高,湘农玉27号在90 000株/hm^2与225 kg/hm^2施氮量条件下产量最高;施氮量、种植密度及两者的互作对夏玉米氮素吸收效率与氮肥利用效率影响显著;氮素吸收效率和氮肥利用效率随施氮量降低与种植密度增加而提高;产量与叶面积指数呈显著正相关。2个品种均适应密植机收,适当控制施氮量、增大种植密度,有利于夏玉米氮肥高效吸收与利用。

In order to improve the summer maize cultivation techniques for high yield and high efficiency in Dongting Lake area, field experiments were conducted in 2017-2018 with two machine-harvesting maize varieties (Zhengdan958 and Xiangnongyu No.27) as materials in Taoyuan county, Hunan province. Three nitrogen rates, 150, 225, 300 kg/hm^2 , and three planting densities, 60 000, 75 000, 90 000 plants/hm^2 , were used in the experiments. The results showed that the whole growth duration was prolonged 2-4 days with the increase of N rate and was shortened by the earlier sowing. Zhengdan958 and Xiangnongyu No.27 gained the highest yield under conditions of 90 000 plants/hm^2 and N 150 kg/hm^2 , 90 000 plants/hm^2 and N 225 kg /hm^2 , respectively. The effects of N rate, density and their interaction on N uptake efficiency (NUPE) and N fertilizer efficiency (NFE) were significant, NUPE and NFE were increased with the decrement of N rate and increment of density. These results showed that high planting density suited the studied two varieties and appropriate control the N rate played a positive role in high-efficiency uptake and utilization of N fertilizer.