Study On The Availability And Adsorption-desorption Characteristics Of Inorganic Phosphorus In Calcareous Soils In Western Jilin Province

In this paper,the topsoil of the calcareous soil in the western part of Jilin Province is taken as the research object.Through inorganic phosphorus classification and sorption and desorption experiments,the adsorption and fixation of phosphorus in the calcareous soil and its correlation with the basic fertility index of cultivated soil with acidizing trend were studied.The availability,adsorption and desorption characteristics of inorganic phosphorus in calcareous soil were clarified,and the characteristics of phosphorus components in the soil were revealed,which provided a theoretical basis for the establishment of a model for sustainable development and fertilization of acidified calcareous soil.It is of great significance to enrich the soil fertility and improve it.The main findings are as follows:1?The contents of Ca₂-P and Ca₈-P were more easily affected by external environment,and the variability was significantly higher than that of other inorganic phosphorus forms.The content of inorganic phosphorus in each group was O-P>Ca₁₀-P>Al-P>Ca₈-P>Ca₂-P>Fe-P.2?There is dynamic equilibrium and interaction among inorganic phosphorus in each group.The results showed that the availability of inorganic phosphorus was Ca₂-P>Ca₈-P>Fe-P>Al-P>Ca₁₀-P>O-P.3?In the range of low phosphorus concentration,the adsorption capacity of phosphorus increased obviously,and with the increase of phosphorus concentration,the adsorption capacity increased slowly.The desorption rate showed an increasing trend with the addition of soil,and the slope of the curve was the highest when the phosphorus content was 20mg/kg,then decreased,and then increased slowly.The desorption amount increased with the increase of phosphorus content.Although phosphorus was in dynamic equilibrium in soil,not all fixed phosphorus could be desorbed.4?Soil pH and organic matter content had significant effects on phosphorus adsorption and desorption.The lower the pH is,the better the phosphorus adsorption is,and after the removal of organic matter,the amount of phosphorus adsorption increases greatly.