[Effects of land use change on soil readily oxidizable carbon in a coastal area of northern Jiangsu Province, East China].

Soil readily oxidizable carbon (ROC) is a sensitive index to indicate the early changes of soil organic carbon (SOC), and has important value to research the stability and dynamics of SOC pool under the backgrounds of human disturbance and global climate change. To further understand the effects of land use change on soil ROC, an investigation was conducted on the soil ROC content and related factors in four different land use types (grassland, farmland, poplar-agriculture system and pure poplar plantation) in a coastal area of northern Jiangsu Province, East China. The soil ROC content was in the order of grassland < farmland <c poplar-agriculture system < pure poplar plantation, and the difference was most significant in 0-10 cm soil layer. The ROC and ROC/SOC ratio decreased with increasing soil depth, and had significant differences between different soil layers in any one of the land use types. The soil ROC in the four different land use types had the same seasonal variation trend, with the maximum in summer, followed by in winter and autumn, and the minimum in spring. The soil ROC was significantly negatively correlated with soil pH and soil bulk density, positively correlated with SOC, soil water soluble organic carbon (WSOC), total nitrogen (TN), C/N ratio, and Mg, but less correlated with soil moisture and soil total phosphorus (TP). The results indicated that land use change had significant effects on the spatial distribution characteristics of soil ROC, and soil bulk density, pH value, TN, and SOC were the main factors inducing the differences of soil ROC content between different land use types.