Soil Respiration In Pinus Tabulaeformis Plantation During Growing Season In The Taiyue Mountain, China

To understand the effects of thinning intensity on soil respiration, an experiment was conducted in Pinus tabulaeformis plantation with four different treatments of0%(CK),20%(slight thinning),30%(middle thinning),40%(intensive thinning) in the Taiyue Mountain of Shanxi Province. Soil respiration rates and the temperature and moisture content at soil depth of5cm were measured from May to September in2011and2012using LI-8100system. The results showed:1) the analysis of variance in the first year indicated that thinning increased the CO2flux, and the soil respiration increased with the increasing of thinning intensity. In the next year it indicated that soil respiration rate of the farming samples, besides the middle thinning one, are all lower than it of the last year. Soil respiration of the slight thinning sample is lower than it of the control sample.2) The soil surface CO2flux was correlated with soil temperature and moisture, and it indicated that the model of double factor can describe the variance of soil respiration better than either of them.3) The value of O10.is lower in the farming samples, except the slight thinning one, than it in the control sample in the first year after thinning. And in the next year, the Q10values in farming sample are all higher than it in the control sample. Our findings suggest that in order to reduce CO2emissions after thinning, the reasonable thinning intensity should be about20%.