[Research on mineralization process of organic phosphorus in black soil in Northeast China]

Buried bag and incubation experiments were conducted to study mineralization process of organic phosphorus in black soil in Northeast China under different time sequences. The results showed that both the content and mineralized velocity of organic P decreased gradually as time went on, the cumulative mineralized rate increased step by step, whether it was used by the method of incubation or buried bag. Under incubation, two treatments' mineralized velocity reached the maximum at first month (31.67, 38.75 mg x kg(-1) x month(-1), respectively), and their cumulative mineralized rate and mineralized velocity at six months were 7.94%, 13.26 mg x kg(-1) x month(-1) and 9.24%, 17.99 mg x kg(-1) x month(-1), respectively. Under buried bag, the mineralized velocity of five treatments all reached the maximum at first year (55.67, 55.65, 49.60, 19.71, 22.52 mg x kg(-1) month(-1), respectively), and the cumulative mineralized rate and mineralized velocity of maize root and wheat root treatments at three years both were approximately 50% and 35 mg x kg(-1) x month(-1), which were higher than those under soybean root andgrass root treatments. From two methods of studies on the mineralization process of organic P, it could be seen that the original content of organic P influenced its mineralized rate and mineralized velocity: the higher of the original content of organic P, the higher of its mineralized rate and mineralized velocity.