增密减氮对嫩单18产量和氮素利用率的影响

Effect of Increasing Density and Reducing Nitrogen Fertilizer on Yield and Nitrogen Utilization Rate of ‘Nendan 18’

以紧凑耐密型玉米品种嫩单18为试验材料。设置2个种植密度:60000株/hm2和75000株/hm^2;设置4个施氮量:0(N0)、120kg/hm(2N1)、240kg/hm(2N2)和360kg/hm(2N3)。探究栽培密度与氮肥施用水平对耐密型玉米品种嫩单18单株及群体干物质积累特性、氮素转运效率、氮素利用效率、产量及其构成因素的影响。结果表明,同一种植密度条件下,氮肥施用水平对千粒重、穗粒数、产量、花后单株干物质积累量、花后群体干物质积累量和氮素利用率影响显著;增加种植密度,同一施肥水平下嫩单18的千粒重和穗粒数显著降低,花后氮素同化量对子粒的贡献率随着施氮量的增加而减少,营养器官氮素转运量对子粒的贡献率随着施氮量的增加而增加,这与低密度种植情况相反,表明高密度条件下花后营养器官氮素转运量对提高玉米产量的贡献较大。因此,根据品种特性适当增加种植密度、减少氮肥用量能够更好地协调群体与个体间的关系,提高群体的光能和养分利用效率,从而获得更高的产量。综合玉米子粒产量和氮肥利用率,嫩单18的适宜栽培模式为密度75000株/hm^2、施氮量240kg/hm^2。

The dense tolerant maize variety‘Nendan 18’was used as the test material. Two planting densities of 60 000 plants/ha and 75 000 plants/ha were set and four nitrogen application rates of 0(N0), 120 kg/ha(N1), 240 kg/ha(N2) and 360 kg/ha(N3) adopted. The effects of planting density and nitrogen application rate on the dry matter accumulation characteristics, nitrogen transport efficiency, nitrogen use efficiency, yield and its components of the dense tolerant maize variety‘Nendan 18’were studied. The results showed that under the same planting density,1 000-grain weight, grain number per spike, yield, dry matter accumulation per plant, post-anthesis population dry matter quality and nitrogen utilization rate were significantly affected by nitrogen fertilizer application rate. As planting density increased, the 1 000-grain weight and the number of kernels of‘Nendan 18’decreased significantly while the fertilization level was the same. As the nitrogen application rate increased, the contribution rate of nitrogen assimilation to the grain density decreased after flowering, whereas the contribution of nitrogen transport from vegetative organs to grain increased. This performance was opposite to that of low-density planting, which indicating that nitrogen transport from vegetative organs was the main factor to increase maize yield at high-density conditions.Therefore, according to the characteristics of the variety, increasing the planting density and reducing the amount of nitrogen fertilizer can better coordinate the relationship between the group and the individual, and improve the light energy and nutrient utilization efficiency of the group, thereby higher yield was gotten. Integrated considering maize grain yield and nitrogen fertilizer utilization, the suitable cultivation mode of‘Nendan 18’was that the planting density at 75 000 plants/ha and the nitrogen application rate at 240 kg/ha.