Transformation of phosphorus fractions in paddy soil amended with pig manure

Abstract

This paper examines phosphorus forms following application of organic fertilizer. Dynamic changes in the phosphorus fraction content were simulated by the waterlogged incubation method. This study was carried out using comparison tests between sterilized and non-sterilized treatments to analyze the effect of organic fertilizer on phosphorus form transformation. The experimental results showed that fertilization of paddy soil could signifcantly increase the content of the phosphorus fraction (p<0.05). Furthermore, the organic phosphorus content increased during incubation. The levels of organic phosphorus in the non-sterilized treatments were higher than in the sterilized treatments. However, the variation of the inorganic phosphorus content was contradictory. A signifcant correlation (r=-0.484, p≤0.01) was observed between O-P and highly resistant organic phosphorus, as well as among Al-P, Ca-P, moderately labile organic phosphorus and moderately resistant organic phosphorus. Therefore, it is concluded that applying organic fertilizer can increase the content of the phosphorus fractions of paddy soil. With microorganisms present, Al-P and Ca-P can be transformed into moderately labile organic phosphorus and moderately resistant organic phosphorus, and O-P can be transformed into highly resistant organic phosphorus.