Effects Of Straw Returning And Chemical Fertilization Application On The Character Of Potassium In Phaeozem

Phaeozem is an important soil resources of the corn production in the Songliao Plain. The soil have superior physical and chemical properties, rich content of soil fertility and potentially effective high fertility is the main characteristic of phaeozem. Study the influence of phaeozem potassium nutrition with straw returning on soil and the combined application of N P K, it can help us found the transformation and mechanism of different potassium nutrition forms in soil with the current system of continuous corn and fertilizer, provide a theoretical basis for the rational application of the use of straw and potassic fertilizer.In order to reveal the variation of the potassium in phaeozem with the long-time straw returning on soil and the combined application of N P K, and to found the effect of potassium forms and the soil properties in the different fertilizing methods. This article take the phaeozem as the object of study, we use the long-term experiment combining with laboratory analysis method to research the potassium forms of the soil and potassium adsorption-desorption characteristics in the different fertilizing methods. The main results were drawn as follow:1. Under the condition of straw, compared to the treatment without K, application of potassium fertilizer can improve the content of available potassium, soil water soluble K,non-specifically adsorbed K, specifically adsorbed K, slowly available K; and the content of total potassium and mineral potassium has no change in application of potassium fertilizer.Compared with N, P fertilizer treatments, the content of available potassium of long-term application of N, P fertilizer of soil will be decreased, which greatly reduce the content of soil available potassium in the treatment of NP.Under the condition of straw, straw treatment can significantly improve the content of available potassium in soil, water soluble K, non-specific adsorption of potassium, and straw on soil special adsorption of potassium is also decreased and increased, in this experiment, the treatment of straw the soil total K and mineral K content at the lowest level.2. Through the rate of various potassium’s content to total potassium we can know,application of K and straw in long-term can accelerate mineral K transform to available K(water soluble K、non-specifically adsorbed K)and slow-available K, it exploit the potential of the soil,and the result of combined application of K and straw is the best.3. The result by adsorption test showed that. Freundlich equation have the well fitting of isotherm adsorption of K by soils with out application of K, and Freundlich equation is not suitable for the soil with application of K. The fitting parameters of equation as follows, 1/n(thevalue of 1/n be smaller, the soil adsorption reaction of potassium will be more great): the treatment of apply fertilizer without K and straw < the treatment of apply straw < the treatment of apply K < the treatment of combined application of K and straw; the value of KF( KF and adsorption capacity of K are positively correlated): the treatment of apply fertilizer without K and straw > the treatment of apply straw > the treatment of apply K > the treatment of combined application of K and straw. Application of K and straw all reduce the soil adsorption capacity of K. And Application of N K has little influence for soil K adsorption capacity.4. In the desorption test: irrespective of application of K and straw, apply N or P can increase the amount of desorption; but N and P can not influence the amount of desorption by the soils with application of K and straw.