种植密度对高粱冠层结构及光辐射特征的影响

Influence of Planting Densities on Canopy Structure and Light Radiation of Sorghum

本研究旨在探讨种植密度对高粱冠层结构及光辐射特征的影响。试验设4个密度处理分别为15.4万、19.2万、25.6万和38.5万株/hm^2,以绥杂7为试验品种,采用随机区组设计,小垄双行种植。结果表明在25.6万株/hm^2种植密度条件下,产量显著高于其他处理,此密度处理生育后期群体叶面积指数降幅较小,光合有效辐射值上升较大,消光系数较大,叶片分布极差小,冠层结构及光分布均较优,利于高粱叶片的光合生产及产量的增加。本研究认为25.6万株/hm^2是优化高粱冠层结构,提高其产量的合理种植密度。

The purpose of this experiment was to investigate the effects of plant density on canopy structure of sorghum and light radiation. The experiment set 4 density treatments： 1.54× 105plants/hm2, 1.92×105plants/hm2, 2.56× 105plantsdam2 and 3.85× 105plants/hm2. Suiza 7 was the test variety. Random block design and small ridge-double line planting method were adopted in the experiment. The results showed that the planting density 2.56× 105plants/hm2 treatment yield was significantly higher than other treatments. Under this planting density, the later growth stages leaf area index （LAI） was declined slightly, the photosynthetically active radiation （PAR） increased greatly, the population average extinction coefficient （K） was higher, the range of leaf distribution （LD） were lower, the canopy structure and distribution of light radiation were excellent. 2.56×105plants/hm2 planting density was beneficial to the photosynthesis production and yield increase. This study suggested that 2.56×105plants/hm2 were reasonable planting density, which could optimize sorghum canopy structure and increase yield.