[Temperature sensitivity of organic C mineralization in gray forest soils after land use conversion]

A laboratory incubation test was conducted to study the organic C mineralization in gray forest soils after land use conversion and the temperature sensitivity of the mineralization. It was shown that after the conversion from wildwood land to farmland, the organic C and total N contents in 0-10 cm and 10-20 cm soil layers decreased by 68.5% and 76.8%, and 40.5% and 44.4%, and the average mineralization rate and cumulative mineralization of soil organic C in farmland were 24.4%-43.2% and 9.20%-13.7% of those in wildwood land, respectively. At lower temperature (< 25 degrees C), there was no significant difference in the temperature sensitivity of soil organic C mineralization between the two land use types; while at higher temperature ( > 25 degrees C), this temperature sensitivity in farmland soil was higher in 0-10 cm layer but significantly lower in 10-20 cm layer, compared with that in wildwood land soil.