不同密度棉花化学封顶的效应研究

Research of cotton Chemical Topping under Different Density

探讨种植密度与打顶方式对棉花产量和纤维品质的互作效应，分析化学封顶代替人工打顶的可行性。选用当地主栽品种，采用裂区设计，主区为密度，设每公顷9万株、18万株和27万株3个密度；副区为打顶方式，设不打顶、人工打顶和化学封顶3种。每个副区面积45m2，重复3次，收获期测定不同棉花品种间的农艺性状及产量。结果表明：不同密度下，棉花叶面积系数与种植密度成正比；不同密度下打顶方式对棉花叶面积系数、棉花单株干物质、产量均没有显著性差异；不同密度对棉花株高没有影响，但不同打顶方式对株高差异显著；且在18万株/hm2不打顶下棉花收获指数最高。

This research explored the interaction effect between planting density and multi-topping methods on the output and fiber quality of cotton; while it also analysed the feasibility of replacing handwork topping with chemical topping. In order to achieve this, The research executed a split-plot experiment, it adopted the mainstream cotton cultivar as the subject, and designed two plots with three settings each, the main plot was set as the density, with three sectors of 90; 180 and 270 thousand plants per hectare respectively, while the second plot was the topping method, with no topping; handwork topping and chemical topping as the three sectors. The testing area was 45 m2 for each sector, and the test repeated for 3 times; at the end of the experiment, plant traits and production were measured. As the results demonstrated, the cotton^s leaf area increased with the plant densities proportionally; while under different density settings, the topping methods did not have significant impact on the cotton’s leaf area, dry matter and production; the density setting had no influence on cotton plant height, yet the topping methods had great effort on the height; while the production index reached the highest under the density of 180 thousands per hectare with no topping method.