密度与氮肥对关中灌区夏玉米(Zea mays L.)群体光合生理指标的影响

合理的密度是玉米构建良好群体结构、优化群体光合生理功能的基础,适宜的氮肥施用量是玉米进行光合生产的营养物质保障.运用作物群体生理学的方法,采用二次饱和D试验设计,研究了关中灌区夏玉米密度与氮肥耦合和群体光合生理指标的关系及其效应,明确了在关中灌区夏播条件下,在45000～75000株/hm2的密度范围内,密度与玉米籽粒产量、总干物质积累量(DMA)、吐丝期叶面积指数(MLAI)、总光合势(LAD)、平均作物生长率(CGR)为正相关,在45000～60000株/hm2的密度范围内,密度与玉米叶片平均净同化率(NAR)为正相关,而在60000～75000株/hm2的密度范围内,密度与玉米NAR为负相关;在氮素施用量≤600.0 kg/hm2的范围内,氮素施用量与玉米籽粒产量、DMA、CGR为正相关,在氮素施用量≤260.55 kg/hm2的范围内,氮素施用量与玉米MLAI、LAD为正相关,与玉米NAR为负相关,而在氮素施用量260.55～600.0kg/hm2的范围内,氮素施用量与玉米MLAI、LAD为负相关,与玉米NAR为正相关.密度对其影响较大的指标为:籽粒产量、DMA、LAD、CGR和MLAI , 影响较小的指标为:NAR;氮肥对其影响较大的指标为:DMA、CGR、籽粒产量、NAR,影响较小的指标为:LAD和MLAI .对籽粒产量和群体生理指标的综合影响效应,密度显著大于氮肥,玉米生产中,尤其要重视合理密植.通过对回归模型的解析,筛选确定了陕单8806玉米在关中灌区夏播中,实现高产的密度与氮肥耦合优化技术方案:合理密度为61713～66177株/hm2,适宜纯氮施用量为309.88～569.02kg/hm2.

Effects of planting density and nitrogen fertilization on population physiological indexes of summer maize(Zea mays L.) in Guanzhong irrigated zone

The reasonable plant density was the base of constructing the good population and optimum population physiological functions of maize,the suitable nitrogen application was the base of nutrition matter of maize photosynthate production.The D-saturation optimum design and crop population physiology were used to investigate the effects and relationships of plant density and nitrogen fertilization on population physiological indexes and yields of summer maize in Guan-zhong irrigated zone.The results showed that the relationship of plant density and grain yield,DMA(dry matter accumulate),MLAI(max leaf area index),LAD(leaf area duration),CGR(crop growth rate)are positive in the range of 45000-75000 plants/hm2;The relationship of grain yield and leaf NAR(net assimilation rate)were negative in the range of 45000-60000 plants/hm2,while its were positive in the range of 60000-75000 plants/hm2.The relationship of nitrogen application and grain yield,DMA,CGR were positive when nitrogen were less applied 600.0kg/hm2 per hectare.When nitrogen were less applied 260.55 kg/hm2 per hectare,the relationship of nitrogen application and MLAI,LAD were positive while the relationship of nitrogen application and NAR were negative.During the nitrogen application range of 260.55-600.0kg/hm2,the relationship of nitrogen application and MLAI,LAD were positive while the relationship of nitrogen application and NAR were negative.The influence of plant density on grain yield,DMA,MLAI,LAD,CGR were higher than that of NAR.The influence of nitrogen application on grain yield,DMA,NAR,CGR were higher than that of MLAI,LAD.The effect on the grain yield and population physiological indexes of maize Shandan8806 were more significant than that of nitrogen application,summer maize shaandan8806 should be reasonable plant density in its production.The optimum technology programs of the factors of summer maize in Guan-zhong irrigated zone were given: the optimum combinations of plant density date and nitrogen application were 61713-66177 plants/hm2 and 309.88-569.02 kg/hm2 respectively under the conditions of the experiment.