广西典型喀斯特地区深层土壤有机碳矿化及其影响因素

以广西典型峰丛洼地草地和原生林深层土壤(70～100cm)为对象,利用微生物交叉接种培养试验,研究不同土地利用类型、土壤微生物群落和通气条件对深层土壤有机碳矿化的影响。在124d的培养期内,微生物接种改变了0～28d原生林和0～81d草地深层土壤有机碳矿化速率,而通气条件变化对这一过程没有明显影响。3因素方差分析结果显示,深层土壤有机碳累积矿化率受土地利用类型、微生物群落和通气条件的影响显著(P<0.01),且存在3因素间交互效应。研究结果对于深入认识喀斯特深层土壤有机碳稳定机制和评估碳储量及其周转具有重要意义。

Organic carbon mineralization in deep soil layers in typical karst region of Guangxi,South China and related affecting factors

Organic carbon in deep soil layer is a component of soil carbon pool,and its mineralization contributes to the carbon cycle of the whole soil ecosystem.Taking the deep soil layers(70-100 cm) in the grassland and primary forest in typical karst peak-cluster depression area of Guangxi as test objects,and by the method of microbial cross-inoculation and incubation,this paper studied the effects of land use type,soil microbial community,and aeration condition on the organic carbon mineralization in deep soil layer.Within the incubation period of 124 days,microbial inoculation altered the mineralization rate of the organic carbon in deep soil layer of primary forest in 0-28 days and that of grassland in 0-81 days,but aeration condition had little effects.The ANOVA analysis showed that land use type,soil microbial community,and aeration condition had significant effects on the accumulative organic carbon mineralization rate in deep soil layer,and there existed interactions among the three factors.These findings would be helpful to the further understanding on the stability mechanism and turnover of deep soil organic carbon in karst region.