阔叶红松林皆伐后不同恢复方式下土壤有机碳形态与矿化速率变化

Changes of Soil Organic Carbon Morphology and Mineralization Rate under Different Recovery Methods of Broad-leaved Korean pine Forest

土壤有机碳矿化对森林恢复方式有极强的敏感性,为阐明不同恢复方式下土壤有机碳矿化速率及其与碳形态之间的关系,2023年6月选择小兴安岭地区阔叶红松林皆伐迹地区域内2种不同恢复方式下形成的2种林分(天然恢复形成的天然枫桦次生林,人工恢复形成的红松人工林)的林地土壤作为研究对象,以未受干扰的原始阔叶红松林的林地土壤作为对照(PK),采用野外样地设置与调查、土样采集与室内培养及测定相结合的方法,分析有机碳矿化速率对不同恢复方式的响应,并结合土壤碳形态的分布,探究不同恢复方式下有机碳矿化速率与土壤碳形态之间的关系。研究结果表明,1)土壤有机碳矿化速率从第3天开始随着培养时间的延长呈现出不断下降直至趋于平稳的趋势,且矿化速率随着土层的加深逐渐减小;2)原始阔叶红松林(PK)的矿化速率最高、天然枫桦次生林(BC)次之、红松人工林(PM)最低;3)2种恢复方式下土壤的总有机碳、矿物结合态有机碳与非活性有机碳由大到小依次为PK、BC、PM;颗粒有机碳含量由大到小依次为BC、PM、PK;4)培养过程中土壤总有机碳、颗粒有机碳、易氧化有机碳含量与有机碳矿化速率均呈现出一致减小的趋势,且与有机碳矿化量呈显著负相关性,其中易氧化有机碳对土壤有机碳矿化率的影响最大,相关系数为0.622。矿物结合态有机碳和非活性有机碳与土壤有机碳矿化量无显著相关性。综上,相较于红松人工林,天然枫桦次生林增强了土壤有机碳矿化速率,并且在2种恢复方式中,活性有机碳主导着土壤有机碳矿化速率。

Soil organic carbon mineralization is highly sensitive to forest recovery methods.In order to understand the rate of soil organic carbon mineralization under different recovery methods and its relationship with carbon components.In June 2023,the soil of two different forest stands(Natural recovery formed Betual costata secondary forest,artificial recovery formed man-made Korean pine forest)formed under two different recovery methods in the area of Xiaoxing’anling Mountains broad-leaved Korean pine forest clear cut⁃ting site was selected as the research object,and the forest soil of undisturbed original broad-leaved Korean pine forest was used as the control.Using the combination of field sample setting and investigation,soil sample collection and indoor culture and measurement,the response of the organic carbon mineralization rate to different recovery methods was analyzed,and the relationship between the or⁃ganic carbon mineralization rate and the soil carbon form under different recovery methods was explored,combined with the distribu⁃tion of soil carbon form.Research results indicated that,1)The mineralization rate of soil organic carbon decreased with the increase of culture time from the third day until it became stable,and the mineralization rate gradually decreased with the deepening of soil layer.2)The mineralization rate of original broadleaved Korean pine forest(PK)was the highest,followed by Betual costata second⁃ary forest(BC)and man-made Korean pine forest(PM)was the lowest.3)In the soil of two recovery methods,the total organic car⁃bon,mineral-bound organic carbon and inactive organic carbon from large to small were PK,BC,PM;the content of particulate or⁃ganic carbon from large to small was BC,PM,PK.4)The content of soil total organic carbon,particulate organic carbon and easily oxidized organic carbon decreased gradually with the change of organic carbon mineralization rate during the culture process,and had a significant negative correlation with the amount of organic carbon mineralization.Among them,easily oxidized organic carbon had the greatest influence on the mineralization rate of soil organic carbon,and the correlation coefficient was 0.622.There was no signifi⁃cant correlation between mineral-bound organic carbon and inactive organic carbon and soil organic carbon mineralization.Compared with the man-made Korean pine forest,the Betual costata secondary forest enhanced the soil organic carbon mineralization rate,and in the two recovery methods,the active organic carbon dominated the soil organic carbon mineralization rate.