Study On The Potassium Adsorption And Releasion Of Phaeozem In Jilin Province Corn Belt

Central corn belt in Jilin province is one of the three major Corn Belts in the world. Corn income has become the main income for farmers. Phaeozem is the most valuable asset. However, soil fertility has begun to emerge degradation because of a variety of natural factors and the irrational use of human. Particularly, potassium in soil has induced in different gegrees. In this paper, the Phaeozem of Central corn belt in jilin province were selected as study objects. The field investigation and laboration analyisis were performded to study the character of potassium adsorption and releasion and the potassium releasion dynamics of biotite, muscovite, feldspar on different oxalic acid,citric acid,tartaric acid concentration. The main results were drawn as follows: (1) Most of soil reached to equilibrate for long time. There were great differentias on K~+ equilibrium adsorption time and the capacity of K~+ equilibrium adsorption among the different soil, the capacity of K~+ equilibrium adsorption were closely related with soil clay content and CEC; Adsorption rate changes is closely related with the CEC and the clay content. (2) First- order and parabola equation were the best and the worst modles for K adsorption respectively. but there were also some problems when we described K~+ adsorbing kinetics of black soil by the First-order equation. (3) The exchange potassium and interlawer K equilibrated in 60-90min, 270-300min under successive extraction in different extracting time. There were great differentias on equilibrium release quantity, the equilibrium release quantity of exchange potassium and interlawer K are 136.0-476.2mg/kg, 527mg/kg-1330.5mg/kg; quantity of exchange potassium under successive extraction is more than, vailable potassium. But the equilibrium release quantity of interlawer K is less than slowly vailable potassium. The vailable potassium and slowly vailable potassium in soil affect the quantity of exchange potassium and interlawer K. (4) Elovich equation is the most ideal and parabolic equation is the worst dynamics model for exchange potassium releasion . The course of exchange potassium releasion is simple. Parabolic equation and Elovich equation is the most ideal and the worst dynamics model for interlawer K releasion. The course of interlawer K releasion is controled by proliferation. (5) Biotite is activated by three organic acids as the following order: Oxalic acid > citric acid> tartaric acid, muscovite and feldspar is activated by three organic acids as the following order: Oxalic acid > tartaric acid>citric acid. The ability of Oxalic acid activated these three minerals potassium isthe strongest. Potassium of biotite is activated easily. The releasion of K-muscovite is easier than the K-feldspar underoxalic acid and tartaric acid. it is oppositeunder citric acid. (6) Along with oxalic acid, citric acid and tartaric acid concentrations increased, the quantity of k-biotite releasion increased, but the rate of increase was getting smaller and smaller, the quantity of potassium under the sameconcentration of different organic acid are as follows: Oxalic acid > citric acid> tartaric acid. On the contray, along with oxalic acid, citric acid and tartaric acid concentrations increased, the quantity of k-muscovite and k-feldspar releasion decreased. Especially for the extraction of acid used, this trend is particularly evident. Oxalate concentration affected the quantity of k-muscovite is smaller, the citric acid and tartaric acid concentration affected the quantity of k-muscovite is larger. The concentration of oxalic acid is the main reason of releasing quantity of K-feldspar . (7) Index equation is the most ideal dynamics model for k-biotite releasion under different organic acid; Elovich equation is the most ideal dynamics model for k-muscovite releasion under. Oxalic acid, Hyperbolic equation is the most ideal dynamics model for k-muscovite releasion under citric acid and tartaric acid; Elovich equation is the most ideal dynamics model for k-feldspar releasion under different organic acid. A diffusion equation is the worst dynamics model for potassium releasion of biotite, muscovite and feldspar.