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研究深层土壤碳库动态对了解陆地生态系统深层碳汇潜力、应对全球CO2升高具有重要意义。论文以黄土丘陵区人工油松林为研究对象,以撂荒地为参照,分析了不同生长阶段的人工油松林地0~200 cm土层土壤有机碳(soil organic carbon,SOC)和活性有机碳(readily oxidizable carbon,ROC)动态变化特征及其影响因素。结果表明:在0~200 cm剖面上,不同生长阶段油松林SOC含量及储量较撂荒地显著提高。浅层(0~100 cm)SOC平均含量,成熟林为撂荒地的2.03倍,提高最大;其次是中龄林,为1.85倍;最后是幼龄林,为1.59倍。深层(100~200 cm)SOC平均含量,幼龄林、中龄林和成熟林分别较撂荒地提高了1.43、1.38和1.36倍。各生长阶段油松林浅层和深层SOC储量分别占0~200 cm SOC储量的61.0%~69.8%和30.2%~39.0%,不同生长阶段间浅层SOC储量差异显著,但深层SOC储量差异不大。浅层ROC储量,幼龄林、中龄林和成熟林依次提高了54.8%、82.0%和91.6%;深层ROC储量依次提高了32.4%、40.9%和58.1%,且深层储量占0~200 cm土层的31.2%~33.3%。不仅浅层SOC和ROC含量受多个因素的影响,而且深层ROC含量也与油松高度、根系生物量以及枯落物厚度、干重呈极显著正相关。因此,人工林建设不仅显著提高浅层SOC和ROC含量,而且对深层土壤的固碳能力有一定改善。
It is of great significance to study the dynamics of deep soil carbon pool to understand the potential of deep carbon sinks in terrestrial ecosystems and to cope with the global warming of CO2. Taking the artificial Pinus tabulaeformis forest in the loess hilly region as the research object and the wasteland as the reference, the paper analyzed the soil organic carbon (SOC) and the active organic carbon (available carbon) in 0 ~ 200 cm soil layer in different growth stages. oxidizable carbon, ROC) and its influencing factors. The results showed that the SOC content and storage of Pinus tabulaeformis forests at different growth stages were significantly higher than those in fallow land at 0-200 cm depth. In the shallow layer (0 ~ 100 cm), the average SOC content of mature forest was 2.03 times that of wasteland, which was the highest, followed by middle age forest, which was 1.85 times and finally, young forest, which was 1.59 times. In the deep (100 ~ 200 cm) SOC, the content of young, middle-aged and mature forests increased by 1.43, 1.38 and 1.36 times, respectively, compared with the fallow land. The shallow and deep SOC reserves of the pine forests at different growth stages accounted for 61.0% -69.8% and 30.2% -39.0% of SOCs at 0 ~ 200 cm, respectively. There were significant differences in SOC stocks between different growth stages, but there was no significant difference . Shallow ROC reserves increased by 54.8%, 82.0% and 91.6% respectively in turn; young ROC reserves increased by 32.4%, 40.9% and 58.1% in turn, and the deep reserves accounted for 0 ~ 200 cm 31.2% ~ 33.3% of the soil layer. Not only the shallow SOC and ROC contents are affected by many factors, but also the deep ROC contents are also significantly and positively correlated with the height of pine, root biomass, litter thickness and dry weight. Therefore, plantation construction not only significantly increased the content of shallow SOC and ROC, but also improved the carbon sequestration ability of deep soil.