The Dynamic Variation Of Soil Enzyme Activities In Lakeside Wetland In Poyang Lake

Soil enzyme activities played an important role in the transformation of material and energy in the wetland. In order to explore the annual change of soil enzyme activity and it’s effected factors, soil enzyme activities were measured by using the international methods, meanwhile the relationships between soil enzyme activities and soil properties as well as environmental factors in beach soil and lake sediments in Poyang Lake. The results will reveal the differences of the enzyme activities in the spatial and temporal changes between beach soil and lake sediments, and also provide the basis for wetland ecosystem management. The main results are followed:(1) The activities of cellobiase and β-glucosidase in beach soil demonstrated the maximum in September, and the highest activities of chitinase appeared in May. No matter use the soil bases or the organic bases, the enzyme activity trend are same. It is very obvious that the two oxidoreductases response for the organic carbon content. Phenol oxidase activity reached the highest in February and May respectively by representing with the soil base and organic carbon base. The highest peroxidase activity was in November, but the enzyme activities represented by soil base and organic carbon base showed the different differences.(2) Cellobiose enzyme,(3-glucosidase, chitinase and acid phosphatase activities in lake sediment showed the same trend, the activities are high when the temperature increases and the water level rises, the annual trend inverted an "V" shape.(3) The differences among four hydrolase enzyme types in diffenent flooding conditions are related with sampling time, spatial differences are obvious in May,September and November, there was no difference in February. Spatial differences of Phenol oxidase and peroxidase activities are significant, the enzyme activities in the lake sediment of four months are much higher than in the beach soil. (4) The enzyme activities in beach soil are significantly affected by water temperature, the water content are significantly correlated with enzyme activities. The cellobiase and acid phosphatase activities increased were promoted by the elevated temperature, but inhibited the peroxidase activity. pH would promote the phenol oxidase activity and inhibit the cellobiase activity in certain condition. Organic carbon and the total nitrogen would promote the activities. The enzyme activities in lake sediment showed a positive response to temperature and carbon and nitrogen changes, the cellobiase, phosphatase and peroxidase activities were significantly affected by temperature, the other three enzyme activities were impacted by carbon and nitrogen content more significantly. Water temperature increasing can promote Cellobiase and phosphatase activities while inhibit peroxidase activity. pH were significantly inhibited the Cellobiase and β-glucosidase activities. Organic carbon and nitrogen showed significantly promoted to chitinase, β-glucosidase and phenol oxidase activities.In conclusion, enzyme activity dynamics caused by many factors, temperature promotes Cellobiase and acid phosphatase activity, and may affect the soil moisture content thus inhibiting the activity of peroxidase.Water temperature will promote Cellobiase and phosphatase activities but will inhibit peroxidase activities in sediment. Organic carbon and nitrogen will promote the activities of β-glucosidase, chitinase and phenol oxidase in sediment.