Study On The Soil Respiration Character And Soil Labile Organic Carbon Of Four Kinds Of Wetland Environment In Hangzhou Bay

As the important part of the ecosystems carbon cycle, wetland ecosystem include water resistant flooded plant and its emvironment. The area of wetland is a few part of of the land surface,and its soil carbon library is huge,about the whole soil carbon library 3%～68%. There are more than 90 percent of the wetland ecosystem carbon storage store in soil, and the wetland ecosystem is the source and remit of a variety of greenhouse gas. Owing to the interferencing,the moisture reduce, the soil oxidation plant residues strenthen, the decompositon rate of plant residues and peat improve,and soil organic carbon wastage,then more greenhouse gas come from the wetland. Global warming has increased wetland carbon emissions.At present due to climate warming, wetland soil temperature and temperature of wetland energy balance affected, surface water and water area of wetland changes, which has affected the greenhouse gas emissions intensity and wetland carbon cycle mode. Hangzhou bay wetland is one of the main coastal wetland, and is also one of the areas affected by human. Since the reform and opening, there are hm21.33 million wetland reclamation. The costline has remove to north about 10 times 16km.The area of reclamation accounts for about 60% of the city area. The research object are Phragmites communis(LW), Spartina alterniflora(MC), Scirpusm ariqueter(BC) and the beach(GT) in south of Hangzhou bay.We measured the soil respiration by LI-6400 connected with the soil respiration chamber, and determin ate the soil organic carbon and the activity of the soil enzyme, to reveal the characteristics of typical wetland soil respiration, soil emissions of CO2 in Volume and typical wetland soil carbon density distribution. The main conclusions are as follows:(1)The soil CO2 was determinated by Li-6400 photosynthesis system connecting 09 of soil respiration chamber from January 2010 to December on LW,MC,BC,GT wetland.The results showed that:the daly dynamic performance in day more than ningt in summer, showed a clear single peak curve. The daily soil temperature trends are similar, the peak between 13:00 and 14:00,2:00 to 4:00 in the trough between the arrival. The order of four kinds of wetlands soil respiration rate:LW (8.34±4.53) umol/(m2.s)> MC (7.49±4.21) umol/(m2.s)> BC (4.42±2.40) umol/(m2.s)> GT (2.33±1.53) umol/(m2.s).Seasonal dynamics trend of four kinds of soil respiration showed a single peak curve, from the point of view throughout the year, soil respiration rate in the April to October is relatively high, the highest value in July. And the order of the season variation is:summer> autumn> spring> winter.There is a significant corrlation on soil respiration with air temperature,soil temperature at 10 cm depth. The corrlation of soil respiraton with soil temperature is bigger than with the air temperature at LW,MC,GT wetland, and smaller at BC wetland (R-=0.5773).The soil CO2 at LW,MC,BC,GT in a year was 6483.40 g/m2.a,5228.96 g/m2.a,2295.48 g/m2.a,975.48 g/m2. a.(2) The soil was acquisited at LW,MC,BC,GT wetland from January 2010 to December, and determinate the soil organic carbon, the soil enzyme activity and the soil physical and chemical properties, the results show that:The soil microbial biomass carbon content of the annual average: MC(143.79 mg/kg)>BC(138.39 mg/kg)>LW(135.52 mg/kg)>GT(133.03 mg/kg); the average carbon content of soil dissolved as:LW (319.33 mg/kg)> MC(316.47 mg/kg)> BC (286.98 mg/kg)> GT(278.20 mg/kg); the average total organic carbon content:LW(7.87 g/kg)>GT (7.65 g/kg)> MC(7.39 g/kg)> BC(6.81 g/kg).The changes in soil organic carbon in the four wetland types is small, and relatively stable, while microbial biomass C and dissolved carbon of variable.The C.V of soil phosphatase activity, urease,β-glucosidase activity and invertase activity above 50%, even more than 100%.There is a significant negatively correlation on microbial biomass carbon with soil phosphatase, urease,β-glucosidase and the activity of invertase activity, and there is a significant positive correlation on soil soluble carbon with soil phosphatase, urease,β-glucosidase activity in summer.The soil carbon density between0-5cm depth:LW(37.8 t/ha)>MC(36.2 t/ha)>BC (32.9 t/ha)>GT(24.9 t/ha); 10-20cm depth of soil carbon density:LW(92.3 t/ha)>BC(86.8 t/ha)>MC(82.3 t/ha)>GT(78.2 t/ha).(3) To research the response of the soil CO2 and soil enzyme activity to the temperature,we warm artificial to the LW by open top container at Hangzhou bay wetland.the results show that:after the short-term simulated warming treatment, soil respiration rate than Increased 17.36%. There is a good correlation of soil respiration with soil temperature at 10 cm depth. The Q10 of warming is bigger than normal state.The phosphatase, urease,β-glucosidase and Invertase activity after simulated warming in the short term has a different degree.In summary, Soil CO2 emissions and soil active organic carbon storage were studied at Hangzhou bay wetland.We harvest the coastal wetlands of CO2 Emission of soil active organic carbon stocks and annual variation, and carbon sequestration potential of wetlands. These results help us to contribute to the adjustment of the region,and provide the basic data for carbon sinks and emission reduction measures.It is important for practice.