杉木人工林和水稻田土壤呼吸Q_(10)值的影响因素初探

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

通过实验室自然变温实验,利用LI-8100研究温度和培养时间对2种土地利用方式(杉木人工林和水稻田)的土壤呼吸温度敏感性的影响,培养时间为180 d.结果表明,指数模型较好地拟合了土壤呼吸速率与5 cm处土壤温度的关系,并且低温时段优于高温时段的拟合效果.土壤呼吸Q10值随5 cm处土壤温度的升高呈降低趋势,杉木人工林地土壤Q10值由3.18下降到1.40,而水稻田土壤Q10值则由2.97下降到1.51,且二者差异不显著(P>0.05),说明土地利用方式对土壤呼吸温度敏感性影响不大.回归分析表明,林地和水田的Q10值与培养时间均呈极显著的负相关关系,表明除温度外,Q10值的变化还与培养时间有关.

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 （P〉0.05）, 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.