Phosphorus mobilization in the Yeyahu Wetland: Phosphatase enzyme activities and organic phosphorus fractions in the rhizosphere soils

Phosphatase enzymes regulate organic phosphorus (OP) turnover in eutrophic wetland soils, but a clear understanding of their relationships remains elusive. In this study, soil samples were collected from rhizosphere and non-rhizosphere soils of three dominant aquatic plants Phragmites communis, Zizania latifolia, and Scirpus planiculmis in Yeyahu Wetland of Beijing, China to investigate the phosphatase enzyme activities, including phosphomonoesterase, phosphodiesterase and phytase, and the impact on OP turnover dynamics in wetlands. Results demonstrated that soil phosphatase activities in rhizosphere were higher than those in non-rhizosphere for all the three plants. Phosphatase activities were correlated strongly with soil labile organic P, although the relationships showed different trends for the three kinds of phosphatases. Moderate liable organic P had a positive correlation to phosphomonoesterase (r = 0.367, P < 0.01) and phosphodiesterase (r = 0.564, P < 0.01). There was a significant negative correlation between highly resistant organic P and phytase (r = −0.438, P < 0.05), indicating that phytase had obvious effects on the process of degrading highly stable P compounds in soils. These results suggest that phosphatase enzymes regulated OP turnover to increase available P and phytase had a strong impact on wetland P cycle system.