The Forms Of Inorganic Phosphorus Of Black Soil And The Properties Of Phosphorus Adsorption And Desorption In Long-term Location Experiment

Based on a long-term location experiment in JiLin Agriculture University, We have studied the forms of inorganic phosphates and the characteristics of phosphorus adsorption and desorption in this paper.Studied on the forms of inorganic phosphates by Gu Yichu and Jiang Bofan method, the results showed as follows:After long-term location experiments for 20 years, till 2004, the contents of different forms inorganic phosphates are Fe-P>Ca₁₀-P>Al-P>Ca₈-P>Ca₂-P>O-P without P fertilizer, and the trend is different from 1984. As it shows, because the efficiency of Ca₂-P to the crops is high, the contents of Ca₂-P decreased under long-term without P fertilizer; and because it is difficult for occluded phosphate to release, the contents of it are low.The treatments with P fertilizer, the contents of different forms inorganic phosphates are higher than the contents in 1984. Among these treatments it can be seen: the contents of all kinds of inorganic phosphates with P,S₁P,S₂P are higher than NP,S₁NP, S₂NP. And because there is cooperation between N and P, that is to say, when the crops absorb N, it is good to them absorbing P, which decreased the contents of P in soils. In all, the contents of inorganic phosphates with P fertilizer are Fe-P>Al-P>Ca₁₀-P>Ca₈-P>Ca₂-P> O-P, and there is little difference with the treatments of using P fertilizer.Using related coefficient analysis to discuss the relationship between every form inorganic phosphates and available phosphates show that: the characteristic of relationship between available phosphates and Ca₂-P,Al-P, they can drew by Olsen method, however, the activity of Ca₈-P and Ca₁₀-P are worse. Seen from related coefficient, Ca₂-P,Al-P are main components of available phosphates.The test of phosphorus adsorption showed that: the adsorption curls of phosphorus in black soil can be described by Freundlich, Langmuir and Temkin equations, but Langmuir equation is the best, its correlation coefficient is significant. Seen from the adsorption curls of phosphorus in long-term location experiments in black soil, there are great differences in the phosphorus adsorption properties of soil of different treatments under low P added. And with low P added, the trends of phosphorus adsorption are linear. In 1984, the contents of...