Temperature variation and its response to topsoil thickness from reconstruction soil profile filled with coal gangue

The temperature of reconstruction soil with 0-120 cm thickness,soil respiration rate and microbial biomass carbon (MBC) content were determined. The study area is divided into four kinds of monitoring areas for A (15-40 cm),B (40-60 cm),C (60-80 cm),and D (80-100 cm) according to topsoil in order to analyze the reconstruc- tion soil filling with coal gangue profile temperature change with different topsoil thickness and its influences on MBC content and soil respiration. The results show that the highest temperature and temperature change range of surface soil (5 cm) of the monitoring area is A > B > D>C. The annual average temperature of the monitoring area of A and B are higher than C and D for 1 ℃ . The existence of coal gangue will affect the temperature change of soil with 0 -20 cm thickness,and the surface soil temperature amplitude decreases with the increase of topsoil thickness. When the topsoil thickness is greater than 80 cm,the temperature change of the soil layer is almost not affected by coal gangue. The in- fluence of coal gangue on surface temperature increases with the solar radiation increases and the soil layer tempera- ture decreases with topsoil increases. The value of Tc( the temperature influence coefficient of coal gangue on surface soil) can accurately analyze the influence of coal gangue on soil layer temperature and calculate topsoil thickness. There is no obvious correlation between the MBC content and soil temperature. The too thick or too thin topsoil is not conducive to the MBC accumulation,but the topsoil thickness in 60-80 cm is the most conducive to the MBC accumu- lation and its annual average content is 83. 46 mg / kg. Soil respiration rate of reconstruction soil is correlated to soil temperature,but the differences between reconstruction soil with different topsoil thicknesses are mainly affected by coal gangue. With the topsoil thickness increasing,the effects of coal gangue layer on reconstructed soil are reducing. Thus,the respiration rate of reconstructed soil is gradually enhancing with topsoil thickness increasing.