降雨频率变化通过改变热带季风林的非稳定态土壤有机碳浓度来影响土壤有机碳浓度。
Changing rainfall frequency affects soil organic carbon concentrations by altering non-labile soil organic carbon concentrations in a tropical monsoon forest.
机构信息
School of Geographical Sciences, Guangzhou University, Guangzhou 510006, China.
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
出版信息
Sci Total Environ. 2018 Dec 10;644:762-769. doi: 10.1016/j.scitotenv.2018.07.035. Epub 2018 Jul 11.
Soil stores a substantial proportion of carbon (C), making it the greatest terrestrial C pool and pivotal to stabilizing the global climate system. Rainfall amounts and regimes have been changing in many places, but effects of precipitation changes on soil organic C (SOC) stabilization are not completely understood. Considerable attention has been focused on the consequences of changes in rainfall amounts, with rainfall regimes having been less studied. This study was conducted in a tropical climax forest to clarify the effects of rainfall changes on SOC fractions, with permanganate oxidation and density fractionations employed to divide the labile and non-labile SOC fractions. Two rainfall manipulation treatments, i.e., increased rainfall frequency with the total rainfall amount unchanged (IRF) and decreased rainfall amount by 50% with rainfall frequency unaltered (DRA), were conducted for two years, with ambient rainfall (AR) as the control. As a result, the IRF treatment increased the SOC concentration that mainly originated from increases in the non-labile SOC content. Relative to the AR control, the DRA treatment did not change the total SOC concentration although the labile SOC concentration increased. This typically is due to a small proportion of the labile fraction to the total SOC content. Our results suggest that this water-rich mature forest is resistant to rainfall amount changes to a great extent (e.g., decrease of 50% as in the present study) from the SOC stabilization perspective, while changes in rainfall frequency could exert more notable effects.
土壤储存了大量的碳（C），使其成为最大的陆地碳库，对稳定全球气候系统至关重要。许多地方的降雨量和降雨模式都在发生变化，但降水变化对土壤有机碳（SOC）稳定性的影响还不完全清楚。人们已经相当关注降雨量变化的后果，而对降雨模式的研究则较少。本研究在热带顶极森林中进行，旨在阐明降雨变化对 SOC 分数的影响，采用高锰酸盐氧化和密度分级法将易变和稳定的 SOC 分数分开。两年内进行了两种降雨处理，即总降雨量不变的增加降雨频率（IRF）和降雨量频率不变的减少 50%的降雨量（DRA），以自然降雨（AR）作为对照。结果表明，IRF 处理增加了 SOC 浓度，主要来源于非稳定 SOC 含量的增加。与 AR 对照相比，DRA 处理虽然易变 SOC 浓度增加，但并未改变总 SOC 浓度。这通常是由于易变分数在总 SOC 含量中所占比例较小。我们的研究结果表明，从 SOC 稳定的角度来看，这种富含水的成熟森林在很大程度上（例如，本研究中减少 50%）对降雨量变化具有很强的抵抗力，而降雨频率的变化可能会产生更显著的影响。
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