喀斯特森林植被自然恢复过程中土壤可矿化碳库特征

Characteristics of soil mineralizable carbon pool in natural restoration process of Karst forest vegetation

2011年9月,采用空间代替时间方法,研究了茂兰自然保护区喀斯特森林自然恢复过程中土壤可矿化碳库的特征.结果表明:研究期间,喀斯特森林自然恢复过程中不同深度土壤的总有机碳含量、可矿化碳含量和矿化速率随土层加深而减少,随恢复的进程而增加;累积矿化排放量及其速率随恢复的进程增加,其速率随培养时间延长而减小;矿化率随恢复的进程增加,而随土层加深的变化不明显;qCO2值随恢复的进程和土层加深而递减;土壤可矿化碳与凋落物现存量及其分解质量损失率分别呈负相关(r=-0.796)和正相关(r=0.924);土壤生境由早期干扰强烈转向中后期日趋稳定,土壤的固碳能力由早期差、潜力大转向中后期强、潜力小.

By the method of taking space instead of time,an incubation test was conducted to study the characteristics of soil mineralizable carbon pool during the natural restoration of Karst forest vegetation in Maolan Nature Reserve,Guizhou Province of Southwest China.It was observed that the contents of soil total organic carbon（TOC） and mineralizable carbon（MC） as well as the carbon mineralization rate decreased with increasing soil depth but increased with the process of vegetation restoration.The amount of cumulative released carbon and the carbon release rate increased with the process of restoration,but the release rate decreased with increasing incubation time.The soil MC/TOC increased with the restoration process but had less change with increasing soil depth,while the qCO2 decreased with increasing soil depth and through the process of restoration.The soil MC had a negative correlation with the existing litter amount（r=-0.796） but positive correlation with the mass loss rate of the litter decomposition（r=0.924）.Soil habitat changed from strong interference at early stages to relative stability at late stages,and soil carbon sequestration changed from small capacity and strong potential at early stages to large capacity and weak potential at late stages.