Dynamics Of Soil Respiration And Soil Microbial Biomass In A Riparian Zone In Taihu Lake

Riparian area is an important ecotone. However, our understanding of soil biological and ecological process in riparian zone is very lack of. Taihu lake wetland is the third largest freshwater lake in China, and located in the south of Yangtze Delta, which is one of the most important wintering ground and habitat of waterfowl. Based on riparian zone of Taihu lake, soil respiration rate, soil microbial biomass, and ecological factors were investigated. The main results showed that:(1)In the upland experimental area of Taihu riparian zone, the soil had lower moisture, contained less organic matter, carbon, nitrogen, phosphorus, sulfur, etc.(2)Soil respiration rate had a significant seasonal fluctuation in Taihu riparian zone, showing autumn>summer>spring>winnter. The highest soil respiration rate was 7.03μmol/m2s in the September, and the main ranges from 0.5 to 5.0μmol/ m2s. Otherness of soil respiration rate in different season was remarkable, along the water gradient was not remarkable. Soil temperature was the controlling factor of soil respiration in Taihu riparian zone.(3)Soil microbial biomass carbon had a significant seasonal fluctuation in Taihu riparian zone, showing autumn> spring> summer. The concentration of soil microbial biomass carbon decreased with distance from the water body(257.88mg/kg, 257.34mg/kg, 146.91mg/kg), and the Otherness of it was not remarkable. Soil microbial biomass carbon was significantly affected by soil moisture, soil organic matter, total carbon, nitrogen, phosphorus, sulphur.(4)Soil available nitrogen had a significant seasonal fluctuation in Taihu riparian zone, showing autumn(64.75mg/kg)> spring(23.29mg/kg)> summer(14.57 mg/kg), being lower in plant vigorous growing season. The area near the water body had higher Concentration of soil available nitrogen. Soil available nitrogen was affected by soil total nitrogen, soil microbial biomass nitrogen, moisture.(5)The concentration of Mcirobial nutrient substance was discrepant and decreased with distance from the water body (The concentrations of SMBN were 61.10mg/kg, 42.52mg/kg, 32.24mg/kg in order; the concentrations of SMBP were 48.82mg/kg, 43.05mg/kg, 16.69mg/kg in order.). Soil Mcirobial nutrient substance was significantly affected by soil organic carbon, soil microbial biomass carbon, soil nitrogen, phosphorus, soil moisture.(6)The concentration of soil total carbon, sulfur, organic matter , NH4+-N, NO3--N in seasonally flooded area were more than the terrestrial facies radiation area's. Soil respiration rate in seasonally flooded area was higher. The concentration of soil total nitrogen in seasonally flooded area was less.