Research on the Yield Effects of the Density of Insect-resistant Cotton and Potassium Fertilizer in Huaibei Area

[Objective] The aim was to search for the most reasonable density and potassium fertilizer application amount,which were suitable for the production of insect-resistant cotton in Huaibei area.[Method] With Zhongmian 45 as tested cotton,the effects of density and potassium fertilizer application amount on the production and production characters of common insect-resistant cotton were discussed by quadratic D-saturation optimization design.[Result] The effect of potassium fertilizer on the fruit nodes number and bolls number of common insect-resistant cotton was positive,but in the whole flourishing period of growth,that of density was negative.Analysis on the yield equations of seed cotton,lint and prefrost harvested seedfiber indicated that the effects of density and potassium fertilizer on the 3 kinds of yields were positive and expect that the interaction effect on prefrost harvested seedfiber was very little,the positive interaction effects on seed cotton and lint were greater.When the density was 40 005-44 775 kg/hm2 and the potassium chloride was between 436.5 and 529.5 kg/hm2,the 3 yields were all highest.The effect was best when half of the potassium fertilizer was applied as base fertilizer and the other half was applied in the early flower period.[Conclusion] The research provided technological support for the abundant harvest of cotton foison in Huaibei area.