Effect Of Potassium Application Methods On Growth,Yield And Quality Of Cotton

To study the effects of potassium application methods on cotton agronomic characters, dry matter accumulation, cotton yield and fiber quality, some experiments were carried out on loam soil at the Lukou farmland in Ezhou, and Huazhong Agriculture University, Hubei province between2011and2013. The experimental material was hybrid cotton H318. All these experiments were double-factors experiments. In2011, the two experimental factors were potassium amount and split application or not. In2012, these two factors are different period and assign rate of potassium application. In2013, the same experiments finished in2012were repeated by the way of field experiments and pot experiments. The main conclusions are listed as follows:The amount, the times, the periods, and the allocation of K fertilizer application did not have significant effects on the height of the cotton, the diameter of the stem, the number of functional leaves and the SPAD values of the main stem. Fertilizing between before transplanting and at peak bloom stages of cotton with the proportion of1:1or1:3, could make the dry weight of the plant and reproductive organs reaching the peak value.The increase of the K fertilizer improved the fiber index when the K2O fertilizer was used as basal dressing and less than240kg/hm2. The fiber index reached its peak value when the K2O application was240kg/hm2. Applying the K fertilizer at potting periods and squaring periods with the proportion of1:3, could obtain the maximum values of the number of fruit branches and fruit nodes, and the number of bolls on per plant, as well as the maximum seed cotton yield.When the amount of K2O application was120kg/hm2, using it at before transplanting and at squaring period with the proportion of1:1would get a high seed cotton yield.When the amount of K2O is120kg/hm2, the average length of the fiber of upper part in each layer reached its maximum value if all the K fertilizer was used as basal dressing. When the amount of K2O is240kg/hm2, fibers with high micronaire values would be produced, if the fertilizer was used at before transplanting and at peak bloom stages with the proportion of1:3or used at squaring period and at peak bloom stages with the proportion of2:1. When the amount of K2O is240kg/hm2, fibers with high elongation rate would be produced if the fertilizer was used at before transplanting and peak bloom stageswith the proportion of2:1. When the amount of K2O is240kg/hm2, fibers with the highest specific breaking strength would be produced if the fertilizer was used at before transplanting and squaring period with the proportion of1:1.Accordingly, the maximum seed cotton yield could be obtained if the amount of K2O is120kg/hm2and used as basal dressing and at squaring period. When the amount of K2O is240kg/hm2, the maximum seed cotton yield could be obtained if the fertilizer is used as basal dressing and at squaring period with the proportion of1:3. In real conditions, the mode of K application should be determined by the soil fertile state, the production requirements, and so on.