Simulation Research On The Impact Of Freezing And Thawing Cycles Of Black Soil Various Forms Of Inorganic Phosphorus Content

In the black soil areas in Northeast China, the average day and year’s temperature are large difference, every spring thaw of freezing and thawing alternating a frequently and longer duration.Freezing and thawing have loss of a great influence of the soil phosphorus transformation of migration.Phosphorus is a trace element necessary for crop growth,and determines the productivity of the soil. Inorganic phosphorus is the main part of phosphorus in the soil.How many different forms of inorganic phosphorus in soil phosphorus content is the decisive factor in how much content.Freezing and thawing is an important factor of Soil Inorganic and phosphorus forms and transformation,have a direct or indirect impact on the soil about how many phosphorus validity and content. Phosphate series of physical and chemical processes applied after the soil has occurred and thus affect the validity of the cropsThis test uses indoor simulation about spring thaw cycles of freezing and thawing conditions, black soil as the research object, freeze-thaw cycles (FTC), the soil moisture content (W), phosphorus soil background value (APb) of aluminum phosphate (Al-P), iron phosphate (Fe-P), the impact occluded phosphorus (O-P) and Calcium (Ca-P) content, According to these studies derived forms of inorganic phosphorus in three changes of factors and conditions, linear relationship between phosphorus and Olsen-P, derived crop fertilizer demand and the desired optimum soil moisture, and soil phosphorus status and potential environmental risks.The main conclusions are as follows:(1) The impact of the freeze-thaw cycles (FTC) to four forms of inorganic phosphorusThroughout the process of freeze-thaw cycles,0～5 cycles of different forms of inorganic phosphorus content in more severe? with the increase of the number of cycles, the content changes gradually leveled off, and most of adjacent freeze-thaw cycles of the various forms have a significant difference. Analysis of variance freeze-thaw cycles on various forms of inorganic phosphorus content incremental absolute dominant.(2) The impact of thesoil moisture (W)to four forms of inorganic phosphorusThroughout the process of freeze-thaw cycles,four kinds of inorganic phosphorus forms a water content of 40%,50% and 60% have more similar variation, when 40% of the difference between before and after freezing and thawing change the maximumAl-P, Fe-P and Ca-P was 6.88 mg·kg-1,8.18 mg·kg-1 and 7.5 mg·kg-1, Occluded P O-P in 30% of the difference between the maximum variation of 36.3 mg·kg-1 Analysis of variance throughout the freeze-thaw cycle, in addition to the occluded phosphorus O-P not significant impact on the other three forms of inorganic phosphorus are of significant influence.(3) The impact of thesoil phosphorus background values (APb) to four forms of inorganic phosphorus. Throughout the process of freeze-thaw cycles,background increase available phosphorus values directly increase the absolute amount of four kinds of forms of inorganic phosphorus, after the freeze-thaw cycles of various forms of inorganic phosphorus content of the absolute size of the O-P> Fe-P> Al-P> Ca-P. Phosphorus background value in 40 mg·kg-1～100 mg·kg-1 significantly regularity, around 80 mg·kg-1 difference between the change in the content of the largest Shi thaw Al-P, Fe-P, O-P and Ca-P was 9.37 mg·kg-1,5.44 mg·kg-1,60.77 mg·kg-1 and 7.44 mg·kg-1. Analysis of variance affect phosphorus content of the background value of the absolute dominant.(4) The effectiveness of the various forms of inorganic phosphorusFour forms of inorganic phosphorus and phosphorus were correlation analysis of inorganic phosphorus validity size Al-P> Fe-P> Ca-P> OP; binding path analysis on the basis of correlation analysis, Al-P and Fe-P are phosphorus source, and direct impact on available phosphorus content, O-P and Ca-P through Al-P indirectly affect phosphorus content. Olsen-P (Y) with the phosphorus source Al-P (X1), Fe-P (X2) obtained linear relationship is Y= (0.021X2+0.228) X1- (0.028X2-0.149) X2-(0.104X2-3.486X+36.994)...