Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance
Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance
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DOI：
10.1111/j.1365-2486.2010.02282.x
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发表时间：
2011-02-01
影响因子：
11.6
通讯作者：
Kaupenjohann, Martin
中科院分区：
文献类型：
--
作者：
Kindler, Reimo;Siemens, Jan;Kaupenjohann, Martin
对不同土地利用系统的碳淋失的估计很少，它们对生态系统净碳平衡的贡献是不确定的。研究了欧洲森林、草地和农田中溶解有机碳（DOC）、溶解无机碳（DIC）和溶解甲烷（CH4）的淋滤。通过δ 13C特征估计了DIC的生物成因贡献。森林的生物源DIC淋滤量为8.3 +/- 4.9 g m-2年-1，草地为24.1 +/- 7.2 g m-2年-1，农田为14.6 +/- 4.8 g m-2年-1。森林的DOC淋失量为3.5 +/- 1.3 g m-2年-1，草地为5.3 +/- 2.0 g m-2年-1，农田为4.1 +/- 1.3 g m-2年-1。各土地利用系统生物碳总通量平均为19.4 +/- 4.0 g C m-2年-1。表层土壤中DOC的生成与其C/N比值呈正相关，而底土中DOC的保留与有机碳与铁+铝（氢）氧化物的比值呈负相关。土壤空气中CO2的分压和土壤pH决定了DIC的浓度和通量，但相对于土壤空气CO2，土壤溶液中DIC往往过饱和。草原生物源碳（DOC +生物源DIC）的淋失相当于净生态系统交换（NEE）的5-98%（中位数：22%）加上施肥后的碳输入减去收获后的碳去除。碳淋失使农田土壤的净损失增加了24-105%（中位数：25%）。对于大多数森林立地，由于CO2在酸性森林土壤溶液中的溶解度小，NEE大，淋滤几乎没有影响实际的生态系统净碳平衡。与其他碳通量相比，CH4的浸出效果不显著。总的来说，我们的研究结果表明，淋失对农业系统的碳平衡特别重要。
Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its delta 13C signature. Leaching of biogenic DIC was 8.3 +/- 4.9 g m-2 yr-1 for forests, 24.1 +/- 7.2 g m-2 yr-1 for grasslands, and 14.6 +/- 4.8 g m-2 yr-1 for croplands. DOC leaching equalled 3.5 +/- 1.3 g m-2 yr-1 for forests, 5.3 +/- 2.0 g m-2 yr-1 for grasslands, and 4.1 +/- 1.3 g m-2 yr-1 for croplands. The average flux of total biogenic carbon across land use systems was 19.4 +/- 4.0 g C m-2 yr-1. Production of DOC in topsoils was positively related to their C/N ratio and DOC retention in subsoils was inversely related to the ratio of organic carbon to iron plus aluminium (hydr)oxides. Partial pressures of CO2 in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO2. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5-98% (median: 22%) of net ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24-105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems.