土地整理对农田土壤碳含量的影响

土地整理对土壤的强扰动会影响土壤的碳循环平衡，为了研究土地整理对农田土壤碳含量的影响，通过间接采样和随机采样方法，采集了江苏3个土地整理区土地整理前后土样进行有机质测定，初步分析了不同土地整理区土地整理后的土壤碳含量变化及其变化差异原因。主要结论有：1）通过土地整理，3个土地整理区土壤碳含量都有得到提高。其中，苏南丹阳土地整理区碳质量分数提高了26.05%，碳密度提高23.87%，提高幅度最大，碳密度变化方向与碳含量变化具有一致性，但提高幅度低于碳含量。这与各整理区原有土质、土地整理工程施工方式、施工时间等因素密切相关。2）水田碳质量分数显著高于旱地碳质量分数，但是经过土地整理旱地碳含量提高幅度大于水田，水田在整理前后碳含量变化幅度不大。3）在土地整理项目实施前应制定适宜的土地整理规划，实施有利于土壤固碳的土地整理工程。

Impacts of land consolidation on soil organic carbon content

Disturbance on the soil caused by land consolidation will affect the balance of soil carbon cycle. In order to study influences of land consolidation on farmland soil carbon storage, soil samples before and after land consolidation were collected and organic matter was measured based on indirect sampling and random sampling in three land consolidation areas of Jiangsu Province. The changes and reasons for the differences of soil carbon storage in different and consolidation areas were analyzed. The results showed that soil carbon storage was increased in all the three land consolidation areas. Organic carbon storage in Dan Yang land consolidation area increased by 26.05%, organic carbon density increased by 23.87% which increased most; Carbon density change shared the same direction with organic carbon storage change, with lower increase than carbon storage. It was closely related to the original soil condition, land consolidation engineering method and construction time of different land consolidation areas; Before land consolidation, organic carbon storage in paddy fields was significantly higher than that in dry fields. After land consolidation, organic carbon storage of dry fields increased a lot more than that of paddy fields, while organic carbon storage in paddy fields remained the same. (3)Reasonable land consolidation planning is required before the implementation of land consolidation project, and land consolidation project which was beneficial to carbon fixation in soil was recommended.