Influence of land use patterns on soil organic carbon decomposition and carbon pools in karst areas of Guilin, China

Organic carbon pools and soil organic carbon (SOC) decomposition are critical parts of the global carbon cycle. Now accurate estimation of the organic carbon pools and SOC decomposition of different land use types are extremely important for the government to establish appropriate policy for land use and to solve the severe issue of the global warming. On the basis of the three-pool first-order theory, we studied the influence of land use change on soil carbon pool in the typical karst area, Maocun, Guilin. The result showed that the total SOC contents of the cultivated land, the shrub, the orchard and the forest land were 15.41-20.10, 13.07-31.16, 9.38-14.74 and 30.82-37.52 g/kg respectively. Ca pool of SOC is 1.01%-2.46%, with an average MRT of 25 days and Cs pool contents 12.81-45.79% of SOC, with an average MRT of 10 years. The Cr pool comprised of 52.63-85.47% SOC. At the very beginning, SOC decomposes relatively quickly, however, the speed of SOC decomposition begins to slow down at late stage. Furthermore, our study also indicate that of the four types of land use, the SOC of the shrub and the cultivated land is stable and the cultivated land has the potential to be a large carbon sink.