Pollution risks of phosphorus in vegetable field soil by application of organic fertilizer

Effect of organic fertilizer application on yield of flowering Chinese cabbage and phosphorus forms were studied in field plot experiment,and contamination risks of vegetable soil phosphorus were evaluated.The results showed that the yield and biomass did not increase while both decreased significantly by excessive application of organic fertilizer.The Fe-P and Al-P were main available phosphorus forms and accounted for more than 90% in vegetable soils.The contents of inorganic phosphorus fractions of vegetable soil were increased using of organic manure,and the larger the amount of application,the greater change of Fe-P、Al-P、 Ca-P and O-P.The excessive organic fertilization will lead to the significantly increasing of Olsen-P and CaCl2-P,which will increase pollution risk of soil phosphorus.By using progressive regression analysis,it showed that there was the linear relationship between Ca-P and Olsen-P,also wise Ca-P was significantly correlated with CaCl2-P(p0.05).The regression equation is Y1 =36.95+0.622 1X and Y2 =-0.102 5+0.048 6X.Ca-P was main source of soil available phosphorus in vegetable soil