Carbon dynamics in subtropical forest soil: effects of atmospheric carbon dioxide enrichment and nitrogen addition
Carbon dynamics in subtropical forest soil: effects of atmospheric carbon dioxide enrichment and nitrogen addition
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DOI：
10.1007/s11368-009-0178-6
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发表时间：
2010-01
影响因子：
3.6
通讯作者：
Juxiu Liu;Guoyi Zhou;De-qiang Zhang;Zhihong Xu;Honglang Duan;Q. Deng;Liang Zhao-
中科院分区：
文献类型：
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作者：
Juxiu Liu;Guoyi Zhou;De-qiang Zhang;Zhihong Xu;Honglang Duan;Q. Deng;Liang Zhao-
目的大气二氧化碳浓度（[CO2]）水平正在迅速增加。了解土壤中碳（C）的动态变化对于评估高浓度CO2下土壤固碳潜力具有重要意义。氮素是未来CO2浓度升高环境下土壤固碳的限制因子。然而，很少有研究已经进行，以探讨会发生什么，在亚热带或热带地区，环境氮沉降是高的。在这项研究中，我们使用开顶箱研究了中国南方实施处理的前4年内，大气[CO2]浓度升高单独以及与氮添加一起对土壤C动态的影响。材料和方法地上和地下C输入（树木生物量）进入土壤，土壤呼吸，土壤有机碳，在每个开顶式培养箱中定期测定总氮和溶解有机碳（DOC）。使用标准土壤取样管（内径2.5 cm），在每个室内从每个土层（0-20、20-40和40-60 cm）随机采集土壤样品。结果与讨论高CO2和高N处理（CN）的土壤C输入量最高，其次是高N处理（N+），仅高CO2处理（C+），然后是不加CO2或N处理（CK）。DOC的渗滤液是小的所有治疗。在我们的实验中，DOC的输出在C循环中起次要作用。总的来说，土壤呼吸速率为CN处理> C +处理> N +处理>对照。除C+处理外，CN处理、N +处理和对照间土壤全氮含量差异不显著。总的来说，土壤有机碳（SOC）的显着影响的处理（p< 0.0001）。各处理土壤有机碳含量的大小顺序为：CN处理> N +处理> C +处理= CK处理。与对照相比，CN和N+处理土壤有机碳含量较高是由于地上部和地下部碳输入量增加所致。增加土壤呼吸在C+处理导致较低的SOC. ConclusionsHeterogeneous大气[CO2]在亚热带中国加速土壤固碳在这方面，但是，这种增加仍需要额外的N输入。土壤碳库的增加是由于树木生长的促进。该地区特殊的气候条件和高密度的植树造林可能进一步促进该地区土壤固碳。
PurposeThe levels of atmospheric carbon dioxide concentration ([CO2]) are rapidly increasing. Understanding carbon (C) dynamics in soil is important for assessing the soil C sequestration potential under elevated [CO2]. Nitrogen (N) is often regarded as a limiting factor in the soil C sequestration under future CO2enrichment environment. However, few studies have been carried out to examine what would happen in the subtropical or tropical areas where the ambient N deposition is high. In this study, we used open-top chambers to study the effect of elevated atmospheric [CO2] alone and together with N addition on the soil C dynamics in the first 4 years of the treatments applied in southern China.Materials and methodsAbove- and below-ground C input (tree biomass) into soil, soil respiration, soil organic C, and total N as well as dissolved organic C (DOC) were measured periodically in each of the open-top chambers. Soil samples were collected randomly in each chamber from each of the soil layers (0–20, 20–40, and 40–60 cm) using a standard soil sampling tube (2.5-cm inside diameter). Soil leachates were collected at the bottom of the chamber below-ground walls in stainless steel boxes.Results and discussionThe highest above- and below-ground C input into soil was found in the high CO2and high N treatment (CN), followed by the only high N treatment (N+), the only high CO2treatment (C+), and then the control (CK) without any CO2enrichment or N addition. DOC in the leachates was small for all the treatments. Export of DOC played a minor role in C cycling in our experiment. Generally, soil respiration rate in the chambers followed the order: CN treatment > C + treatment > N + treatment > the control. Except for the C+ treatment, there were no significant differences in soil total N among the CN treatment, N + treatment, and the control. Overall, soil organic C (SOC) was significantly affected by the treatments (p< 0.0001). SOC for all the soil layers in the treatments followed the order: CN treatment > N + treatment > C + treatment = CK treatment. Compared with the control, the higher SOC in the CN and N+ treatment was due to the greater above- and below-ground C input. The increased soil respiration in the C+ treatment led to the lower SOC.ConclusionsElevated atmospheric [CO2] in the subtropical China accelerated soil C sequestration in this area; however, this increase would still need additional N input. The increased soil C pool was due to the enhanced tree growth. Special climatic condition in this area and the high density of tree planting might further accelerate soil C sequestration in this area.