Study On The Forms Of Phosphorus And Characteristics Of Adsorption--Desorption Of The Corn Belt Phaeozem In Jilin

Study on the forms of inorganic phosphates and their usefulness, the characteristics of phosphorus adsorption and dedorption in the corn belt phaeozem in Jilin ,in this paper .The results showed: In black soil of corn belt in Jilin ,the content of Total-P is 0.089%~0.165%,average content is 0.125% . The content Olsen-P of cultivated horizon in black soil rised 5mg/kg compare with the results of soil investigation in 1979 year .The higher is 51.04mg/kg, the lower is only 6.97mg/kg, average is 21.37mg/kg.In black soils ,the amount inorganic phosphates about 60%~80% in the total-P ,Study on the forms of inorganic phosphates and their usefulness by Gu Yichu and Jiang Bofan method. The results showed: the amount of occluded phosphate is too much than other forms ,its content is 54.5~308.2mg/kg, to the proportion to the total amount of inorganic phosphate is 16.3%~61.0%; the next is Fe-P, its content is 20.5~128.2mg/kg, to the proportion to the total amount of inorganic phosphate is 10.3%~34.1%; the content of other forms of inorganic phosphate are : Ca10-P (content is 29.1-99.7 mg/kg , the proportion to the total amount of inorganic phosphate is 9.5~28.4%)>Al-P(content is 11.9-88.7 mg/kg , the proportion to the total amount of inorganic phosphate is 7.3~16.9%)>Ca2-P(content is 8.4~74.7 mg/kg , the proportion to the total amount of inorganic phosphate is 3.8~15.3%)>Ca8-P(content is 3.4-114.7 mg/kg , the proportion to the total amount of inorganic phosphate is 1.7~24.5%)0 Those average proportion of constitute orderly is O-P:36.5%,Fe-P:21.8%,Caio-P:16.4%,Al-P:12.6%,Ca2-P:8.27%,Ca8-P:4.4%.Use related coefficient analysis to discuss the relation between every form inorganic phosphates and available phosphates , draw the conclusion that: available phosphates that with draw by Olsen's method mainly is Ca2-P, their relativity is very obvious.but Al-P^ Fe-P are valid complemet of Ca2-P.Every form inorganic phosphates is stable relatively on composing. Path coefficient analysis showed that the order of every form of inorganic phosphates effect on available phosphates was: Ca2-P>Al-P>Fe-P>Ca9-P >O-P>Ca10-P. Established the equation between Olsen-P and Ca2-P (x1) ,A1-P (x3) : y=2.433+0.466x1+0.134x3.The characteristics of phosphorus adsorption-desorption were conducted to find out the best equation for the tested soil. It was shown that a single Langmuir equation was the best one to describe the sorption date judged by their very significant correlation coefficients. Freundlich and Temkin equation are the better . By correlation analysis, two-surface Langmuir equation was much better than single Langmuir equation.From the adsorption -desorption data we could learn that adsorption mechanism of soil phosphorus was mainly ligand exchange reaction and chemical precipitation was accompanied in the course of adsorption, pH value had closer relations with phosphorus adsorbed, and it was an important factor to have much effect on phosphorus adsorption. The adsorbed ability of black soil is hard , in adsorbed and desorbed plot have 1~2 turn point, using "Eadie-Hofstee"plot can analyze well the adsorption phenomenon of phosphorate in low denstity.From the line Langmuir equation,we can get the Xm:416.7~555.6mg/kg soil.binding energy constants:2.61~5.43,sorptivity value :1.09~3.02,the reaction of phosphorus adsorption can happen freely.The study of effect element on the phoshorus of adsorption-desorption showed:After eradicating organic matter in black soil ,the content of adsorbed phosphorus is added obviously.The adsorption rate is 97.0% -20.7%,but the higher of desorption rate is only 18.3%.oxic iron and oxic aluminium effect on Xm postitively.