皆伐对锐齿栎林生长季土壤呼吸的影响

Effect of clear-felling on soil respiration of Quercus aliena var. acuteserrata forest during growing seasons

2011年5～10月,利用Li-6400-09系统测定了锐齿栎林及其皆伐地的土壤呼吸速率,同时测定了地下5,10 cm土壤温度和湿度。结果表明:皆伐地和对照林地土壤呼吸速率具有明显的月动态,土壤呼吸速率月均值变化趋势均呈单峰曲线。皆伐地和对照林地土壤呼吸速率与土壤温度具有极显著的指数关系,与土壤湿度具有极显著的二次函数关系。在整个生长季,皆伐地和对照林地土壤呼吸碳通量分别为566.1 g.C.m-2,534.1 g.C.m-2土壤呼吸速率无显著差异。在整个观测期间,皆伐地和对照林地地下5 cm处的Q10值分别为3.13,2.36;地下10 cm处的Q10值分别为3.46,2.56,皆伐地和对照林地土壤呼吸速率对地下10 cm土壤温度变化的敏感性大于5 cm。

Soil respiration rates were measured by Li-6400 portable photosynthesis system with soil chamber in clear-felling site and （control site） from May 2011 to October 2011. Soil temperature and soil water content at 5, 10 cm soil depth were also measured simultaneously. The results show that the soil respiration rates had a significant monthly dynamics with unimodal curve in the clear- felling and the control site; the relationships between soil respiration rate and soil temperature could be described by exponential equations in the clear-felling and the control sites. The relevance between them was extremely notable. The soil respiration rates showed significantly Quadratic function relationship with soil water content in the clear-felling site and the control site. The soil carbon efflux in clear-felling and control site were 566.1g.C.m-2, 534.1goC^m-2; from fourth month to sixth month after felling, the soil respiration rate in clear-cutting site was greater than control site, which was lower than the control site after the sixth month, the soil respiration rate had no significant difference between the clear-felling site and the control site; Q10 values were 3.13, 3.46 at 5 cm, 10 cm soil depth in clear- felling site, and in the control site, Ql0 values were 2.36, 2.56 at 5 cm, 10 cm soil depth. Soil respiration rate was more sensitive to soil temperature changes in 10 cm soil depth than that in 5 cm soil depth.