Distribution, Affecting Factors And Storage Of Soil Organic Carbon In The Center Of The Hilly Region Of Sichuan Basin

Climate change is the most important global environmental issues, also in the global change research is the key. In addition to studying the change of global climate is an accurate understanding of greenhouse gas emissions, the situation vegetation and soil CO₂ absorption of the so-called carbon sink function in recent years has increasingly been to, Previous studies have mostly concentrated in the forest and grassland ecosystems carbon sinks, Chinese typical of the purple soil in hilly areas of farmland has ecosystem-based regional research less, Therefore this paper, the central hilly region of Sichuan soil organic carbon distribution and influencing factors were studied.From the entire section of the carbon contents, the uphill slope-place and middlehill slope-place trends are sparse woodland>cultivated sloping land>grassland, downhill spaces reversed to cultivated cultivated sloping land>grassland>sparse woodland, each slope of the total organic carbon contents of soil profiles are in abundance-enrichment in the 0-5cm level, after the increase with the depth gradually reduced, But in Woodland and sloping land use under the slower rate of decline, grassland and 10 cm depth below the total organic carbon content decreases rapidly.Overall, different land using patterns are readily oxidized organic carbon contents sparse woodland>grassland>cultivated sloping land. Different land using patterns between soil are readily organic carbon differences in the allocation of smaller, Overall allocation ratio deepened with reduced soil, or cleared land in the rate of decline is relatively smaller. arable land decreased by a relatively large margin. Greatly influenced by man-made slope farmland soil their readily oxidized the ratio of organic carbon coefficient of variation is larger.As roots distribution and by other factors, different land used of particulate organic carbon contents in the soil profile show some levels, in place and the uphill slope, were content to sparse woodland>cultivated sloping land>grassland, In downhill spaces reversed to grassland>sparse woodland>cultivated sloping land. Soil particulate organic carbon changes in the allocation of more scattered. In addition to the downhill slope land-there is no obvious with the increase in soil depth decreasing trend, the distribution ratio coefficient of variation for the results show that it remains under artificial factors larger farming soil, Particulate organic carbon contents than dramatic changes.The whole soil profile of the nitrogen contents, different slope of the trend is sparse woodland>cultivated sloping land>grassland, farmland and grassland C/N is drawing near. In three types of land use, grassland soil is relatively high C/N, or cleared the soil of woodsland is relatively low C/N.Different land used patterns of soil particles and aggregates composed of larger changes, CS with soil depth did not change, was reunited with soil depth increases gradually decreased.The soil organic carbon density of study area were 1.69kg C/m²(20cm) and 5.37kg C/m²(100cm) in 1982, the soil organic carbon density were 1.80kg C/m²(20cm) and 5.42kg C/m²(100cm) in 2006, two hours compared organic carbon density increased slightly, but the specific types of soil are each of local type.The soil organic carbon storage of study area were 1.31Tg(20cm) and 4.14Tg(1 00cm) in 1982, the soil organic carbon storage were 1.39Tg(20cm) and 4.18Tg(100cm) in 2006, although slightly higher, but considering that this study is still used in 1982 for the soil area, Therefore, the whole study area of soil organic carbon reserves are declining.Total organic carbon and readily oxidized organic carbon is highly correlated, Of the three land use under its correlation coefficients were sparse woodland>wasteland>sloping farmland, Note by man-made factors affecting the larger soil, the soil organic carbon contents variation greater and more unstable.Different size and total organic carbon in the soil are less relevant, 1～0.05mm between size and total organic carbon was negatively correlated, grassland to a significant negative correlation, Woodland to significantly; 0.05mm～0.002mm negative correlation between the size and total organic carbon were positively correlated, But less relevance than just grassland attained a significant positive correlation; 0.02mm～0.002mm size and total organic carbon between the soil no significant correlation; 0.002mm size and total organic carbon are positively correlated, but only Woodland reached a significant correlation.