Q10 Values of Soil Respiration and Its Affecting Factors for Chinese fir Plantation and Paddy Field

Temperature sensitivities of soil respiration for two land use types(Chinese fir plantation and paddy field)as affected by soil temperature and incubation time were investigated by LI-8100 at laboratory.The incubated time of soil samples were 180 days.The results showed that the relationship between soil respiration and soil temperature at 5 cm depth could be described as exponential equations,and there was better fit at low soil temperature than at high soil temperature;the Q10 value of soil respiration declined with the increasing of soil temperature and,the Q10 value decreased from 3.18 to 1.40 for Chinese fir soil and 2.97 to 1.51 for paddy soil,respectively,but the differences in Q10 between the two land use were not significant(P0.05),indicating that land use types had no effects on the Q10 value of soil respiration in this research.It was also demonstrated by regression analysis that there was a significant negative linear relationship between Q10 value and the incubation time,suggesting that incubation time was,in addition to temperature,one of important factors of Q10 values.