PRELIMINARY RESULTS OF ~(14)C AGE OF SOIL ORGANIC MATTER IN DINGHUSHAN SUBTROPIC FOREST SOILS
Xing Changping;Shen Chengde;Sun Yanmin;Jiang Mantao;Yi Weixi (Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640)
Radiocarbon of soil organic matter (SOM)in Dinghushan subtropic forest has been adjusted by the "bomb-effect". Ages of every soil layers, which are within Holocene,decrease with increasing depth. It suggests that pedogenesis in sites are successive.Pedogenesis rates of Wukesong profile and Kengkou profile are 0. 0233 cm /a and 0.0488cm/a, respectively. The difference of pedogenesis rates can be attributed to microtopography and vegetation. Organic matter of red earth is comprised of the active and inactive (or static) components, of which decomposition rates and average residue time are 0.25-0.57a-1 and 1.8-4.0 a for active components, and 1.51× 10 -3 1 .8 ×10 -3a-1 and 556-667 a for inactive components.