Effects of long-term different straw returning measures on soil phosphorus supply capacity
To study the effects of long-term different straw returning strategies on soil phosphorus adsorption and desorption characteristics of soil phosphorus under the winter wheat-summer maize rotation system in fluco-aquic soil area, with a view to providing a theoretical basis for improving the phosphorus supply capacity of the soil in this area, in this study, based on a long-term (since 2007) field experiment located in Yucheng, Shandong Province, the varia-tions of soil phosphorus availability and soil adsorption and desorption characteristics of phosphorus under four treat-ments were determined, including no straw return (CK), wheat straw return (W), corn straw return (M), and wheat and corn straw return (D). The results showed that compared with CK, straw returning treatments significantly increased the content of soil available phosphorus. The content of available phosphorus in W, M and D treatments was 47.5％,15.4％, and 12.2％ higher than that in CK, respectively, while W, M, and D treatments decreased the content of soil exchangeable calcium by 49.1％, 30.5％, and 31.7％, respectively. In addition, different straw returning strategies showed distinct impacts on soil phosphorus adsorption characteristics. Compared with CK, W, M and D treatments decreased soil phosphorus absorption capacity by 10.7％, 7.5％, and 5.1％, respectively. The maximum phosphorus uptake (Qm) in the soil under W treatment was significantly lower than that under CK treatment, while the Qm was not significantly different between the treatments of M, D and CK. The soil phosphorus adsorption saturation (DPS) was significantly increased by W and M treatments, but it was little impacted by D treatment. The three straw returning treatments significantly increased the phosphorus desorption capacity of soil with the order of W>D≈M>CK, while which significantly decreased the desorption hysteresis coefficient (HI) of phosphorus desorption in soil, with the rule of CK>D≈M>W. The results of correlation analysis showed that the soil exchangeable calcium content was most correlated with the soil phosphorus adsorption and desorption characteristics. These results showed that straw return-ing can increase the soil phosphorus supply capacity by reducing soil phosphorus adsorption and increasing soil phosphorus desorption capacity, and the effect of single season wheat straw returning is better than other two straw returning treatments. The results also indicated that in calcareous fluvo-aquic soil, reducing the fixation of exchangea-ble calcium on phosphorus in soil is a great potential way for straw returning to increase soil phosphorus availability.
万方数据
维普
