Effects of coal dust and temperature on CO₂ emission in two soil types in Shanxi Province

By using incubation experiment, the effects of temperature and coal dust application degrees on soil organic carbon decomposition were measured in two soil types (soils from power generation and coke oven plants) in Shanxi Province. The results show that CO₂ emission rates were higher in the early days under both room temperature (16~23 ℃) and 25 ℃ than those in the rest of the incubation period. In fact, CO₂ emission rate at 25 ℃ was twice that at room temperature. Furthermore, CO₂ emission rate and soil labile organic matter increased with increasing application degree of coal dust. At the highest possible application degree of coal dust, CO₂ emission rate rose to 57.5 mg·kg^-1·d^-1, and labile organic matter content of two soil types increased by 0.3～3.8 g·kg^-1. Under different temperature and application degrees of coal dust, the amount of CO₂ emitted by the power generation plant soil was higher than that emitted by the coke oven plant soil. This may because of much more organic carbon and less clay particular in power generation plant soil. It also suggested that soil organic carbon decomposition was mainly driven by temperature. However, coal dust and soil physical and chemical properties also influenced the soil organic carbon decomposition. More importantly, coal dust increased soil CO₂ emission while it at the same time improved soil carbon pool.