The purple soil was used as the test soil. An incubation experiment in the laboratory was conducted to explore the effects of sudden temperature change on soil organic carbon mineralization of the typical dry land soil (purple soil) sampled from the purple hilly region. Experiment consisted of three treatments

that was

treatment HW (constant temperature 20 ℃)

treatment BW1 (a sudden cooling from 20 ℃ to 10 ℃) and treatment BW2 (a sudden warming from 20 ℃ to 30 ℃). In treatment BW1 and treatment BW2

the sudden temperature change both happened when soil organic carbon (SOC) mineralization rate was basically stable and maintained a relatively lower level at the temperature of 20 ℃(29th day). After the sudden temperature change

treatment BW1

treatment BW2 and treatment HW was cultivated for another 47d. The results showed that sudden temperature change had a notable effect on purple soil SOC mineralization (P <0.05). More specifically

treatment BW2 had significantly promoted soil SOC mineralization

however

treatment BW1 dramatically impaired that. Compared with the constant temperature (HW) treatment

the SOC mineralization rates of the two increased by 225.1% and decreased by 38.5%. There was a significant difference in the amount of SOC accumulated mineralization between each temperature treatment (P<0.05) within initial stage after sudden temperature change (30th ~44th d). And compared to accumulated soil SOC mineralization in treatment HW

that in treatment BW2 and treatment BW1 increased by 40.5% and decreased by 55.3% respectively. But with the extension of the culture time

the amount of SOC accumulation in each treatment did not find a significant difference. Indicated that the effect of sudden temperature change on purple soil SOC mineralization was time-bounded

which remained around two weeks. Combined with mineralization kinetic data

the results showed that sudden temperature change affected SOC mineralization by changing the labile SOC pool size.