Decomposition characteristics of rice straw returned to the soil in northeast China

Abstract

The straw return method has been increasingly implemented in rice production in Northeast China. In-depth studies on the characteristics of rice straw decomposition are of great importance for achieving sustainable agricultural development. In this study, the nylon mesh bagging method was used to study the patterns of rice straw decomposition and nutrient release during a 5-year period of rice growth. The results showed that straw decomposition occurred mainly during the first 3 years after straw return, with the cumulative amount of decomposition reaching 77.0%, and that the rate of straw decomposition decreased linearly with time. The release of carbon, nitrogen, cellulose and hemicellulose occurred mainly during the first and second years after straw return. Moreover, the release of phosphorus and potassium occurred mainly during the first month after straw return, and lignin was released at various rates throughout the entire study period. These results indicated that straw returned to the soil acts both as a source of phosphorus and potassium in the short term and as a source of nitrogen and carbon in the long term during the rice growing season in Northeast China.