Soil enzyme activity and influencing factors in lakeside wetland of Poyang Lake, Jiangxi Province of eastern China

In order to elucidate the change of soil enzyme activity and its influencing factors, we collected soil samples from 0 to 10 cm depth in February, May, September and November 2011 in lakeside wetland, Poyang Lake of eastern China, and measured the soil properties and soil enzyme activities related to organic carbon transformation, meanwhile the relationships between soil enzyme activities and soil properties were examined. The results showed that the changes of soil pH, the concentrations of organic carbon and total nitrogen were not significant through different months in a year. However, the changing trends of soil enzyme activities were significantly different. The activities of cellobiase and β-glucosidase demonstrated a distinct maximum in September; but the highest activity of phenoloxidase appeared in February, and the lowest was in September; the highest peroxidase activity was in November; whereas there was no significant difference for chitinase activity. Correlation analysis showed that the soil water content was negatively related to the activities of phenoloxidase and peroxidase; the soil surface temperature was positive related to cellobiose activity and negative related to peroxidase activity. The contents of soil organic carbon and total nitrogen showed a significant negative correlation with β-glucosidase, and highly significant positive correlation with peroxidase. Our results suggest that the variation of different soil enzyme activity is strongly related to the change of soil water content, and the impact of soil organic carbon and nitrogen on soil enzyme activity is generally weak in lakeside wetlands.