| Gossypium hirsutum L. is typical K-preferring crop, potassium nutrition plays an important role on cotton nutritional function. By analyze the potassium cycle and balance of farmland, reveal K fertility sufficient or not on the present productivity level of cotton field, to forecast the decrease of soil effective K content. By show the effects of potassium fertilizer application on cotton plant potassium nutritional physiology, cotton lint yield and fiber quality, as well as microstructure, construe the potassium fertilizer application of cotton high yield in northern Xinjiang. By analyze various form of K content in different soil grains after continuous bio-exhausting, realize the sustained capability of soil K supply and forecast the dynamic Change of the K in cotton farmland, that has a practical and long-term significance to realize cosmically continuous cropping exhaustion of Xinjiang soils. Using transmission electron micrographs technique and conventional analysis method, a three-year field experiment and pot experiment were carried out on the typical Calcaric Fluvisals soil in northern Xinjiang, through designed with K application and zero K application treatment. The main findings were as following:1)The available K and effective K content of K fertilizer application was higher than zero K treatment. When the lint yield reach 2250 kg·hm-2 such a high level, the soil need 180 kg·hm-2 K fertilizer, and 10000 kg·hm-2 cotton straw, to make the K of soil in a stable level.2) K application advances the cotton development, increases the leaves number, plant height, diameter of stem and reduces the first sympodia branch nodes, enhances the weight of dry matter by 1.9%, debases root shoot ratio of plant. Higher K, N concentration and accumulation, K/N of cotton tissues was obtained under the treatment of K fertilizer application. Cotton functional leaf stomatal movement and chlorophyll fluorescence parameters improved obviously due to K fertilization. Application of K fertilizer was an effective way to optimize cotton yield component factor, i.e. the boll number were 7.4 per plant with the treatment of N300P150K150 and 6.6 per plant with the treatment of control, Fruiting branch number was increased 11.8%. The potassium fertilizer application was 9.28% higher lint yield than control. However, Potassium fertilizer application produced a little effect on cotton fiber qualities.3) The leaves and stem diameter of K application have developed collenchyma, more and larger vascular bundle to enhance absorbing water and nutrient of cotton stems and leaves. K fertilization promote the chloroplast ultra-structure of cotton function leaf. The chloroplasts have regular stroma and grana lamellae, less and smaller osmiophilic granule, to prevent chloroplasts disorganized and runtish after flowering and fruiting stages compare with control.4) Through 10 crop cultivations, the biomass of plants and K absorption were significant reduced of exhaust treatments. They are significant correlation between mineral K, non-exchangeable K and plant K absorption of N300P150K0 treatment. Non-specifically adsorbed and non-exchangeable K of <2μm and 2-5μm particle size fractions were significant reduced of exhaust treatments with harvest number. |
