Study On Soil Organic Carbon Fractions In Different Land Use Types

Soil organic carbon plays crucial roles in soil fertility, sustainable development of agriculture, and balance of ecosystem. Soil organic carbon pool is an important component of the global carbon, and monitors soil quality changes, which mainly reflects the effects of organic carbon on soil fertility, soil natural structure and soil chemical properties. In this study, we compared the soil organic carbon in two different soil types and analyzed the difference of soil organic carbon under human disturbance and natural state, using soil samples collected from the reclaimed minesoils of the aluminum mining wasteland in Xiaoyi County and Lingkong Mountain Nature Reserve in Changzhi city, Shanxi Province, in North China. We chose the optimal agricultural measurement according to the results and the natural conditions of the reclaimed minesoils of the aluminum mining wasteland, which would improve the soil natural structure and make the aluminum mining wasteland a better state, the research may offer technical supports to improve carbon fixation capacity significantly in Chinese abandoned industrial land. The results are summarized as follows:1. We analyzed the effects of different agricultural measurements on different fractions of soil carbon, using soil samples collected from reclaimed minesoils of aluminum mining wasteland in2010in Xiaoyi County, Shanxi Province, in North China. The conclusion is following:(1) Deeper soil corresponded to reducing soil organic carbon and fractions of soil organic carbon but increasing δ13C values under different agricultural measurements.(2) Fertilization significantly increased soil organic carbon content, and mature with chemical fertilizer was the best fertilization pattern. Rotation with fertilization could significantly increase soil organic carbon content, but only rotation could not improve soil carbon contents. Straw returning significantly increased soil organic carbon content, and crushed straw could accumulate much more soil organic carbon than whole straw-mulching. (3) The correlations between soil organic carbon and labile organic carbon, dissolved organic carbon, light fraction carbon, or particulate organic carbon were significantly different. The correlations between soil labile organic carbon and dissolved organic carbon, light fraction carbon, or particulate organic carbon were significantly different. And the correlations between soil organic carbon and pH or cation exchange capacity (CEC) were significantly different.2. We analyzed the correlation among different components of soil carbon and the effects of soil physical and chemical properties on soil carbon, using soil samples collected from Lingkong Mountain Nature Reserve in2011in Changzhi city, Shanxi Province, in North China. The conclusion is following:(1) The contents of soil organic carbon had a significant positive relationship with the labile organic carbon under different vegetation types.(2) The correlation between soil dissolved organic carbon and labile organic carbon was significantly different in the Chinese pine soil, while the correlation was not significantly different in the Quercus liaotungensis. There were significant relationships between soil labile organic carbon and light fraction organic carbon or particulate organic carbon under different vegetation types.(3) The correlations between different fractions of soil carbon and pH were significantly different under different vegetation types, so was the soil organic carbon and moisture content or cation exchange capacity (CEC).3. The contents of soil organic carbon ranged from1.26to5.52g/kg, and the labile organic carbon ranged from1.23to2.07g/kg in reclaimed minesoils of the aluminum mining wasteland, while they were6.06-50.63g/kg,2.64-8.58g/kg in the Lingkong Mountain Nature Reserve, respectively. This could mean that the soil organic carbon in reclaimed minesoils of the aluminum mining wasteland was significantly lower than that in the Lingkong Mountain Nature Reserve. And human disturbance had a significant impact on soil organic carbon, which would destroy the natural structure of soil, and make the soil fertility and soil total carbon reduce.4. The results showed that, soil organic carbon was significantly increased under different reclamation patterns, and the content of soil organic carbon was highest under the treatment of straw returning and mature with chemical fertilizers, which still exists a larger gap compared with the soil organic carbon in the Lingkong Mountain Nature Reserve. Therefore, the existing reclamation patterns would further improve, which would promote the soil carbon cycle while reclaiming the mining wasteland, and create a win-win for improving soil quality and retarding the greenhouse effect eventually.