围湖造田不同土地利用方式下土壤呼吸季节动态及其对温度的敏感性

Seasonal Fluctuation and Temperature Sensitivity of Soil Respiration in Reclaiming Land from Lake under Different Land Uses

[目的]为了研究围湖造田对碳循环以及对区域乃至全球气候变化的影响。[方法]以太湖流域肖甸湖区为试验地,利用LI-6400-09土壤碳通量观测仪,分析了该处围湖造田区香樟（Cinnamomum camphora）林、水杉（Metasequoia glyptostroboides）林、毛竹（Phyllostachys heterocycla）林和农田4种不同典型土地利用方式土壤呼吸的季节动态与温度敏感性。[结果]不同土地利用方式土壤呼吸具有一致的显著季节变化,其季节变化主要受土壤温度的控制。香樟林、水杉林、毛竹林、农田的月平均土壤呼吸速率分别为0.384～3.070、0.603～3.960、0.611～5.850和0.333～4.820μmol/（m2·s）,年变异幅度分别为7.99、6.57、9.57和14.47。香樟林、水杉林、毛竹林、农田的Q10值分别为2.54、2.21、2.82、2.17;林地土壤呼吸对温度的敏感性大于农田。[结论]与相同气候区旱地森林相比,围湖地区土壤呼吸速率较高,Q10值较大,表明在未来全球气候变暖的背景下,围湖地区可能比旱地土壤向大气释放更多的CO2。在研究全球碳循环的过程中,围湖造田对碳循环的影响应给予充分的考虑。

[Objective] The research aimed to study the effects of reclaiming land from lake on the carbon cycle and climate changes in the region and the globe. [Method]The seasonal fluctuation of soil respiration was measured monthly by LI-6400-09 in Cinnamomum camphora forest,Metasequoia glyptostroboides forest,Phyllostachys heterocycla forest and a cropland in the reclaiming land from Xiaodian lake area,Wujiang City,Jiangsu Province. [Result] There was a significant seasonal fluctuation of soil respiration under each land use. Soil temperature was the main factor controlling the seasonal fluctuation of soil respiration. The monthly mean of soil respiration ranged from 0. 384 to 3. 07 μmol/（ m2·s） in Cinnamomum camphora forest,ranged from 0.603 to 3.960 μmol/（ m2·s） in Metasequoia glyptostroboides forest,ranged from 0. 611 to 5. 850 μmol /（ m2·s） in Phyllostachys heterocycla forest,and ranged from 0. 333 to 4. 820 μmol/（ m2·s） in the cropland, with the annual variation scope 7. 99,6. 57,9. 57 and 14. 47,respectively. Q10value of soil respiration was 2. 54 in Cinnamomum camphora forest,2. 21 in Metasequoia glyptostroboides forest,2. 82 in Phyllostachys heterocycla forest,and 2. 17 in the cropland,respectively. Q10value in forest lands was higher than that in the cropland. [Conclusion]The soil respiration and Q10value were higher in the impoldering land relative to the upland of the same climate zone,indicating that under the background of global warming,imploding land might emit more CO2than upland. It was important to note the effect of reclaiming land from lake on the carbon cycle.