樟树人工林土壤呼吸的动态变化

Diurnal and Seasonal Dynamics of Soil Respiration In Cinnamomum camphora Plantation

以长沙市城市森林中的樟树人工林为研究对象,用LI-COR-6400-09测定樟树人工林生长期土壤呼吸的日变化、全年的季节变化,并分析其与土壤温度因子之间的关系.结果表明:土壤呼吸的日变化呈单峰曲线,最高值出现在15:00～20:00,最低值均出现在早晨5:00～6:00,与5cm处土壤温度变化相一致,呈显著正相关;季节变化呈不规则的曲线格局,年均土壤呼吸速率为443.52mg.m-2h-1,最大值为976.54mg.m-2h-1,出现在7月下旬5cm处土壤温度最高时,最小值为23.13mg.m-2h-1,出现在1月下旬5cm处土壤温度最低时;樟树人工林土壤呼吸的季节变化与土壤温度呈显著的指数相关,拟合方程为Rs=0.1598e0.1355t,R2=0.949,P<0.000,土壤温度可以分别解释土壤呼吸变化的94.9%;土壤呼吸温度敏感性Q10值为3.88.

Taking Cinnamomum camphora plantation among Changsha＇s urban forests as study object and using LI-COR-6400-09 gashouse to link LI-COR-6400 portable CO2/H2O analysis system, the paper conducted a study of the diurnal and seasonal dynamics of soil respiration during its growth. The results show that the diurnal change of its soil respiration accords with that of its soil temperature at 5 cm depth, both having a significant positive relationship in between with a single value peak and taking on the highest value at 15：00;20：00 and the lowest at 5：00-6：00; that it has a seasonally irregular eurvilinear pattern of CO2 flux process： its average soil respiration being 443.52 mg · m^-2h^-1, its highest being 976.54 mg·m^-2h^-1 in late July and its lowest being 23.13 mg·m^-2h^-1 in late January; that the seasonal change of its soil temperature has an index relation with that of its soil respiration and the former can explain 94. 9% of the changes in the latter; and that the relationship between soil respiration rate （Rs） and soil temperature （t） can be described by the regression equation： Rs ： 0. 159 8e^0.135 5T（R^2= 0. 949, P〈0. 000） and the sensitivity Q10 value is 3.88.