Effect of manure on transformation of organic phosphorus in paddy soil
Dynamic change characteristics of organic phosphorus content were analyzed by the method of waterlogged and non-sterilized incubation. The results showed that the content of organic phosphorus increased over time. As expected, the content of organic phosphorus increased with the content of organic fertilizer applied. It was found that the average amplitude of organic phosphorus was 43. 65 mg · kg-1. The result that the influence of organic fertilizer on organic phosphorus fractions was different in order as highly resistant organic phosphorus > labile organic phosphorus > moderately resistant organic phosphorus > moderately labile organic phosphorus was indicated. A highly significant positive correlation between fertilizing content and labile organic phosphorus ( r = 0.486 ** ) , fertilizing content and highly resistant organic phosphorus ( r = 0. 713 ** ) were observed. Significant positive correlation existed between decreasing amplitude of total inorganic phosphorus and moderately resistant organic phosphorus ( r =0. 381 * ) , decreasing amplitude of total inorganic phosphorus and highly resistant organic phosphorus ( r = 0.300* ). On the basis of correlation analysis, it was concluded that phosphorus in organic fertilizer could directly transform into labile organic phosphorus and highly resistant organic phosphorus, inorganic phosphorus into moderately resistant organic phosphorus and highly resistant organic phosphorus indirectly.