其他摘要：In the context of global change, it is of significance to study the effect of alternative drying-wetting on the soil fertility level and the environmental quality of water body. In this study, soil P was fractionated by using a modified Hedley fractionation method to examine the effect of alternative drying-wetting on phosphorus fractions in soils with different organic matter content. The results displayed no significant difference of total phosphorus between the two treatments because the coefficient of variance was less than 10%. However, there is a significant change in the distribution of soil phosphorus fractions: increase the content of labile-P (especially resin-P) and organic-P (NaHCO3-Po, NaOH-Po and Con.Hcl-Po) while decreasing the content of NaOH-pi and occlude-P. Under the alternative drying and wetting condition, resin-P increased by 121% in the organic soil, while only increasing by 31% in the sterile soil, which indicates a significant effect of alternative of drying and wetting on labile-P in soils with high organic matter content. The study indicates that alternative drying and wetting seemed to drive the phosphorus transformation from the occlude-P to labile-P and organic-P. In the context of global change, alternative drying and wetting can increase the content of labile P in the soil to improve crop growth. However, when there is rainfall or irrigation, it may aggravate the loss of soil phosphorus, which will induce the offshore eutrophication and possibly threaten the coastal environmental quality and regional ecological security.
