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在90000、75000、60000株/hm2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/hm2较为适宜。
Under the planting density of 90000, 75000 and 60000 plants / hm2, the change of micro-habitat and the occurrence of leaf spot in the canopy of Xundan 20 were studied. The results showed that during the silking stage, the upper canopy wind speed had a negative correlation with the planting density, and was greater than the middle and lower wind speed. There was no significant difference in wind speed between different planting densities during filling stage. There was no significant difference in the light intensities of the upper layers between different planting density groups at different growth stages of maize. However, there was a significant difference in the light intensity between the middle and lower layers, especially in the middle ear, which showed that the light intensity was negatively correlated with the planting density. During silking stage, the temperature of upper layer showed high, medium density was higher than low density, while there was no obvious difference between different planting densities during filling stage. The temperature of middle layer and lower layer was low at high density at about 13:00 in silking and filling periods In the high-density. Population humidity and planting density was positively correlated, and the lower humidity followed by higher than the middle and upper. Corn leaf spot aggravates with increasing planting density. Combining with the yield analysis, it showed that the planting density of Xundan 20 was more than 75000 plants / hm2.