Characteristics Of Forest Soil Organic Carbon Distribution And Mineralization In Changbai Mountain

To get more acquainted with the spatial distribution and mineralization characteristics of forest soil organic carbon in Changbai Mountain, this experiment using the method of Line Transect Method chooses two typical forest types, Korean pine broad-leaved forest and broad-leaved forest, to conduct the study on the distribution of soil total organic carbon, light and heavy organic carbon fractions in different profiles, slope directions and altitudes. Meanwhile, the mineralization rates of organic carbon mineralization in two forest types are determined by indoor culture method. The results show that:The contents of total, which are decreased with increased depth in the soil profiles, show obvious vertical distribution characteristics. The content of the soil organic carbon is greatly influenced by the profile layers, and the contents of soil total, light and heavy fraction organic carbon in the Korean pine broad-leaved forest and broad-leaved forest in 0-5cm humus layer are significantly higher than those of the deposition layer soil. The contents of soil total, light and heavy organic carbon in the Korean pine broad-leaved forest and broad-leaved forest are less affected by the position of the slope and altitude in Changbai Mountain. The vertical spatial distribution of organic carbon density varies with different slope positions. The soil organic carbon density of the Korean pine broad-leaved forest and broad-leaved forest in Changbai Mountain is between (2.1+0.7)× 105 kg/hm2. and (0.6 ± 0.1)× 105kg/hm2.The distribution of light and heavy organic carbon are the same as that of soil total organic carbon in the Korean pine broad-leaved forest and broad-leaved forest. The contents of light and heavy fraction organic carbon are decreased as the depth increases. The proportion of the heavy fraction particles increases and the proportion of the light, fraction particles decreases with increased depth in the soil profiles. The soil are mainly composed of heavy fraction particles in the Korean pine broad-leaved forest and broad-leaved forest, and the content of the organic carbon in heavy fraction is higher than that of the light fraction. The content of heavy fraction organic carbon is significantly higher than that of light fraction in the 0-5cm, below 5cm humus layer and deposition layer.The incubation time influences the mineralization amount and rate of soil organic carbon. As the incubation time is prolonged, the cumulative mineralization of soil organic carbon (C02) increases and the mineralization rate of soil organic carbon decreases, tending to be stable. There is a significant difference in the mineralization process of organic carbon in soil with different profiles. The overall performance is that the surface soil organic carbon mineralization rate is fast, the amount of mineralization and release of CO2 is high, and the mineralization rate of soil organic carbon in the deposited layer is low. The slope direction and altitude don’t affect significantly the mineralization rate of organic carbon.