| The representative of black soil in corn belt of the Songliao plain was used as the soil for experiment, and then researched P horizontal and vertical distribution characteristics of high yield and control group soil which was artificial directional cultivating. Discussed the research on P adsorption and desorption characteristics and differences. The results showed:Songliao Plain corn with black profile of total phosphorus,Obvious phenomenon of accumulation of the available phosphorus content in the topsoil.In the same occurrence of the level of high-yield soil phosphorus content significantly higher than the control soil, high-yield field cultivated soil phosphorus content ranged from0.844g/kg-0.442g/kg, average0.612g/kgï¼›Control field soil tilth and total phosphorus content ranged from0.668g/kg-0.286g/kg average0.501g/kg22.0%higher yield field soil than in the control soil;yield field cultivated soil available phosphorus content ranged from35.9-25.3mg/kg, the average31.8mg/kg;control field soil available phosphorus content ranged from18.0mg/kg-11.7mg/kg mean15.5mg/kg, high-yield field soil is1.05times higher than the control field soil.1979second national soil survey results available phosphorus content ranged from15.0-30.0mg/kg, an average of15.3mg/kg and comparative analysis of the results of this survey, high-yield field soil available phosphorus content is higher than the maximum value of1.8mg/kg control field soil available phosphorus content is higher than average levels of0.2mg/kg.Using Jiangbo Fan-Gu Yichu classification methods, the lime soil inorganic phosphorus in the early care benefits were measured by Ca2-P Ca8-P, A1-P, Fe-P, O-P and of Ca10-P six forms of inorganic phosphorus. Yield field average soil inorganic phosphorus content in the topsoil is1.4times that of the control field soil. The composition of the high-yield cultivated soil of various forms of inorganic phosphorus as follows:of Calo-P (38.9%-16.0%)> Al-P (31.7%-21.2%)> Fe-(23.9%-10.1%)> the, Ca8-P (34.3%-14.2%)> Ca2-P (10.6%-4.8%)> O-P (2.0%-1.4%). Control the various forms of the cultivated soil inorganic phosphorus composition of Ca10-P (42.9%-27.2%)> A1-P (27.9%-20.2%)> Fe-P(18.3%-8.0%), Ca8-P (34.8%-16.7%)> Ca2-P (8.6%-2.0%)> O-P (2.9%-1.4%).Take a typical profile in the Songliao Plain Corn Belt the pear victory Township and pear million rounds of high-yield and its control soil as the tested soils were analyzed. The lowest proportion of the O-P in the total inorganic phosphorus with the profile to deepen the soil Ca-P the, Cag-P, Al-P, Fe-P, the absolute content and the relative content of high-yield field soil basically above the control Tian soil, and with the increase in soil depth, the absolute content of no particular law, but the relative content increases; With the increase in soil depth soil in the absolute content of the Ca10-P high-yield slightly higher than the control soil, but the relative content of high-yield is lower than the control soil. Phosphorus Forms such as the correlation with Olsen-P content as the soil available phosphorus source, the Ca2-P the, Cag-P, Fe-P and A1-P can be regarded as a source of available phosphorus corn with black. In the Yield field soil, the average content of available phosphorus source for245.0mg/kg, accounting for73.7%of the total topsoil inorganic phosphorus; in the control field soil, the average content of available phosphorus source150.6mg/kg, accounting for the plow layer of inorganic phosphorus the amount of62.9%.Phosphorus adsorption and desorption tests showed that high-yield field soil external source of phosphorus adsorption capacity is generally small, the desorption amount and desorption rate is relatively high, the ability of the crop for phosphorus is generally better than the control soil. In summary, soil phosphorus adsorption point the greater the number, showed a strong adsorption with adsorption saturation is lower desorption at the same time the phosphorus in the soil the more difficult. |
