沼泽垦殖前后土壤呼吸与CH_4通量变化

湿地是陆地生态系统的重要组成部分,在碳的储存中起着重要作用。湿地垦殖后,在相同季节根层土壤温度明显高于沼泽湿地土壤,但垦殖后土壤有机碳、氮素含量明显降低,C:N比值减小,土壤呼吸通量增大,且具有季节性变化。垦殖8年的农田土壤,呼吸通量大于垦殖15年的农田土壤,弃耕后土壤有机碳含量及土壤呼吸强度有所增加,土壤呼吸通量与土壤温度呈显著正相关关系。沼泽湿地土壤为大气CH4的重要源,通量季节性变化明显,沼泽垦殖后农田土壤成为CH4的汇,不同垦殖年限土壤间CH4通量差异性不大。

Difference of Soil Respiration and CH4 Flux Between Mire and Areble Soil

Wetlands is the important part of terrestrial ecosystem, and plays a significant role in global carbon cycling. The soil temperature of rhizosphere is distinctly higher after cultivation of mire soil , but soil organic carbon and nitrogen levels, and C: N ratios decreased notably after reclamation. The soil respiration flux increased after cultivation of the mire soil and showed characters of distinct seasonal dynamics. On the other hand, the respiration flux was larger when areble period was conger. The soil respiration flux had the significant positive correlation with soil temperature. The mire soil was a important sources of the atmosphere CH4, and showed notable seasonal dynamics, but the soil became a sink of atmosphere CH4 after reclamation, and therer was no significant difference of the CH4 flux between 8 and 15 years.