| Global temperature change caused by the greenhouse gases is one of hotspot of the global change studies. Global carbon cycle study is a key to the change. Forest soil plays an important role in global carbon cycle,but emphasized a lack of fundamental knowledge of soil carbon dynamics. Dinghushan Biosphere Reserve is one of ideal regions that can make up the blank because of its unique feature. Some parameters,such as 14C,soil organic matter,total nitrogen and pH,are measured in Wukesong profile,Qingyunsi profile and Kengkou profile. Conclusions given follow as.Red earth of Dinghushan Biosphere Reserve are all products of Holocene. The maximums apparent 14C ages are 5572a for Wukesong profile,8663a for Qingyunsi profile,283 Oa for Kengkou profile,respectively.Organic matter of red earth is comprised of the active and inactive (or static) components,of which decomposition rates and turnover times are 0.29-0.56 a-1 and 1.8-3.4 a for active components,and <1.02 X 10-3 a-1 and >621 a for inactive components.There is an apparent positive linear correlation between 14C ages and depths. Ages of every soil layers decrease with increasing depth. The correlation indexes of fitting function between I4C ages and depths are all over the significant level.Pedogenesis efficiencies of red earth are 39.988 a/cm for Qingyunsi profile,38.355 a/cm for Wukesong profile and 19.735 a/cm for Kengkou profile,repectively. The difference of pedogenesis efficiency may be attributed to microtopography and vegetation.Organic carbon fluxes of red earth are 28.62g C-cm-2.a-1 for Wukesong profile,24.40g C-cm-2.a-1 for Wukesong profile and 9.39g C-cm-a'1 for Kengkou profile,respectively. Average organic carbon flux of Dinghushan Biosphere Reserve is 22.76g C-cm'a"1. Total exchanged organic carbon of Dinghushan Biosphere Reserve is up to 2.72X1012gC annually.The correlation of SOM-Total N,pH-SOM,pH-Total N,Depth-SOM,Depth-Total N are over the significant level at P=0.01.
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