Abstract: Soil carbon cycle in aquatic-terrestrial ecotone (e.g., riparian zone) is an important component of global carbon cycle, but few researches are made on it. Taking a typical riparian zone of Taihu Lake near Suzhou as the object, three experimental sites along a soil moisture gradient, i.e., from the near of water body to the high mound, were installed in this paper, with the soil water soluble organic carbon (WSOC) and light fraction organic carbon (LFOC) contents and their correlations with soil physical and chemical factors analyzed. Soil moisture had obvious effects on the surface soil (0-10 cm) active organic carbon. The surface soil WSOC and LFOC contents decreased along the soil moisture gradient, but the variation degree of these contents in deeper soil layers became smaller. The WSOC and LFOC contents were significantly higher in surface soil than in subsurface soil, which was in accordance with the variation trends of soil organic carbon and nitrogen. In different soil layers at each site, the WSOC and LFOC were all significantly positively correlated with soil total organic carbon, total nitrogen, and moisture, suggesting that the latter three parameters could be the main factors controlling soil active soil organic carbon.

Key words: Triticum aestivum, Thermo-photo-sensitive genic male sterile line, Fertility transition, Thermo-sensitive period, Critical temperature