长白山阔叶红松林生态系统土壤呼吸作用研究

 用密闭静态箱式法观测了长白山阔叶红松林生态系统生长季中的土壤呼吸作用。结果表明，长白山阔叶红松林生态系统土壤呼吸作用日动态呈单峰曲线，在18∶00左右达到最大值。土壤呼吸作用在生长季中的动态呈单峰曲线，7月最大。6、7、8、9各月平均土壤呼吸作用分别为0.22、0.32、0.23和0.13 gC·m-2·h-1。温度升高可以提高土壤呼吸作用强度，地下5 cm的土壤温度比气温更能准确地反映土壤呼吸作用的动态变化；土壤水分含量在一定范围内增加可使土壤呼吸作用强度增加，但水分过多也会对土壤呼吸产生抑制作用而导致土壤碳排放减少。

SOIL RESPIRATION IN BROAD-LEAVED AND KOREAN PINE FOREST ECOSYSTEMS, CHANGBAI MOUNTAIN, CHINA

The emission of carbon from soils to the atmosphere occurs primarily in the form of CO2 as the result of soil respiration. Increased storage of carbon in soil could help offset further anthropogenic emissions of CO2, whereas a release from soil could significantly exacerbate the increase of atmospheric CO2 and reinforce the greenhouse-warming effect. Because of the enormous carbon storage in soils, even a small change in soil respiration will be equal to or even exceed the annual CO2 input into the atmosphere from land use changes or burning of mineral fuels. Thus, changes in soil respiration can have a significant positive or negative impact on atmospheric CO2 concentrations and therefore affect climate change. Controlling soil respiration potentially can abate increases in atmospheric CO2 concentrations. To understand the soil respiration dynamics of the broad-leaved and Korean pine forests at Changbai Mountain, and to provide a scientific basis for quantitatively assessing carbon source/sink relationships, soil respiration in broad-leaved and Korean pine forests at Changbai Mountain was measured using a static closed chamber method. The results indicated that the diurnal dynamics of soil respiration presented a single-peaked curve with the maximum occurring around 18∶00. The seasonal dynamics of soil respiration also showed a single-peaked curve with the maximum occurring in July during the growing season. The mean soil respiration rates during the growing season were 0.22 gC·m-2·h-1 in June, 0.32 gC·m-2·h-1 in July, 0.23 gC·m-2·h-1 in August, and 0.13 gC·m-2·h-1 in September. Increasing temperatures would accelerate the soil respiration rate. Compared to air temperatures, soil temperatures more precisely reflect the dynamics of soil respiration. More soil water in a certain range would improve soil respiration rates, but excessive water in soil would restrain soil respiration rates and decrease CO2 emission rates from the broad-leaved and Korean pine forests.