浚单20不同密度群体冠层微生境研究

在90000、75000、60000株/hm~2种植密度条件下,研究了浚单20吐丝期、灌浆期群体冠层的微生境变化及叶斑病发生情况.结果表明,在吐丝期,冠层上层风速与种植密度呈负相关,且大于中、下层风速;在灌浆期,中、下层风速不同种植密度间差异不明显.在玉米不同生育时期,不同种植密度群体的上层光照强度差异均不显著,但中、下层尤其是中层穗位处的光照强度差异较大,表现为光照强度与种植密度呈负相关.在吐丝期,上层的温度表现为高、中密度大于低密度,在灌浆期不同种植密度间差异不明显,中层和下层的温度在吐丝期和灌浆期午后13:00左右时低密度高于中、高密度.群体湿度与种植密度呈正相关,且下层湿度依次高于中层和上层.玉米叶斑病随着种植密度的增加而加重.结合产量分析表明,浚单20种植密度以75000株/hm~2较为适宜.

Study on Canopy Microhabitat of Xundan20 in Different Planting Densities

Population canopy microhabitat of Xundan20 was researched at stage of silking, grouting in three dif-ferent densities, 90 000, 75 000 and 60 000 plant/ha.The results showed that, at stage of silking, wind speed in canopy upper had negative correlativity with planting densities, and was stronger than that in middle and lower layer.Wind speed in middle and lower layer had no significant difference among different planting densities at stage of grouting.Light intensity in middle and lower layer intensity had negative correlativity with planting density, while light intensities in upper were no significant difference among different planting densities at different stages.Temperature in upper at stage of silking had positive correlativity with planting density, while it had no significant difference at stage of grouting among different planting densities.Temperature in middle and lower layer about 13:00 at stage of silking and grouting had negative correlativity with planting densities.Humidity had negative correlativity with planting den-sity.Humidity in lower layer was bigger than that in middle and upper layer.The leaf spot disease was more severe with the increase of planting density.Combination microhabitats of different planting densities and their grain yields, considering that the suitable planting density of Xundan20 was 75 000 plant/ha.