Soil Labile Organic Carbon With Different Land Uses in Reclaimed Land Area From Taihu Lake

Abstract

Land reclaimed from lakes is a human disturbance to ecosystems that has frequently occurred in China since the late 1950s. To gain a better understanding of the characteristics of soil labile organic carbon in the reclaimed land from a lake under different land uses of the Xiaodian Lake area, the concentrations and proportions of microbial biomass carbon (MBC), water-soluble organic carbon (WSOC), readily oxidizable carbon (ROC), and particulate organic carbon (POC) in the 0- to 40-cm soil layer were analyzed. The amount of MBC under cropland (CL) was significantly greater than that in the three forest types. The concentrations of MBC at 0- to 10-cm, 10- to 20-cm, and 20-to 40-cm depth in the CL were 508.44 ± 14.95 mg·kg−1, 389.09 ± 34.97 mg·kg−1, and 167.10 ± 25.30 mg·kg−1, which was 1.23-, 2.01-, and 1.68-fold greater than that in soils from Cinnamomum camphora; 1.80-, 2.52-, and 1.76-fold greater than that under Metasequoia glyptostroboides; and 1.19-, 1.30-, and 1.35-fold greater than that under Phyllostachys heterocycla forests, indicating that the disturbance of cultivation and fertilization in the CL had a great effect on microbial activity. The amounts of WSOC, ROC, and POC were lower in the CL than in the forests. The proportions of WSOC (0.89%-3.59%) and ROC (16.07%-35.45%) were greater than those in highland forests of the same climate zone, whereas the proportions of POC (3.43%-17.28%) were lower, implying that the stability of soil organic carbon was poor in impoldering land. Thus, reclaiming of land from a lake area significantly alters the carbon cycle. Thus, it is important to develop a better understanding of the effect of reclaimed land from a lake on carbon cycle.