Decomposition and nitrogen dynamics of litter in peat soils from two climatic regions under different temperature regimes
Decomposition and nitrogen dynamics of litter in peat soils from two climatic regions under different temperature regimes
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DOI：
10.1016/j.ejsobi.2005.09.017
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发表时间：
2006-04-01
影响因子：
4.2
通讯作者：
Laiho, R
中科院分区：
文献类型：
--
作者：
Domisch, T;Finér, L;Laiho, R
土壤温度是影响有机质分解的主要因素，因此，全球变暖可能会加速分解过程。然而，尚不清楚气候不同的地区是否会产生类似的影响。研究了5℃、10℃和15℃土壤温度对樟子松腐烂的影响。在为期一年(360天)的生长室实验中对针进行了评估。来自两个气候不同的泥炭地(芬兰南部和北部)的完整泥炭核心被用作孵化环境。将针叶培养在苔藓层下面的落叶袋中，每隔60天测定一次质量损失和氮(N)浓度。在5摄氏度的处理中，随着时间的推移，针的质量损失率明显低于更高的温度。质量损失与土壤温度积累量密切相关。在高于5摄氏度的温度下，北部泥炭的质量损失更大。此外，北部泥炭的分解极限值(渐近最大质量损失)(92%)略高于南部泥炭(87%)。N浓度增加到质量损失50-60%，然后下降，而N的量(作为原始量的百分比)保持不变，直到质量损失50-60%，然后线性下降。看来，土壤温度的升高可能会导致北部泥炭的针叶凋落物质量损失率略高于南部泥炭的针叶凋落物质量损失速率和随之而来的N释放。北部泥炭在较高温度下分解较快，加上略高的最大质量损失值，表明随着气候变暖，北部泥炭地成为大气碳源的敏感性可能向北增加。(C)2006年爱思唯尔公司。版权所有。
Soil temperature is a major factor affecting organic matter decomposition and thus, global warming may accelerate decomposition processes. However, it remains unclear whether the effects will be similar in climatically different regions. The effects of soil temperatures of 5, 10 and 15 degrees C on the decomposition of Scots pine (Pinus sylvestris L.) needles were assessed in a 1-year (360 days) growth chamber experiment. Intact peat cores from two climatically different peatland sites (southern and northern Finland) were used as the incubation environments. Needles were incubated in litter bags beneath the living moss layer, and mass loss and nitrogen (N) concentration were determined at 60-day intervals. The rate of mass loss from the needles over time was clearly lower in the 5 degrees C treatment than at the higher temperatures. Mass loss was strongly related to the accumulated soil temperature sum. In temperatures higher than 5 degrees C, mass losses were higher in the northern peat. Also, the limit value of decomposition (asymptotic maximum mass loss) was slightly higher in the northern peat (92%), than in the southern peat (87%). The N concentration increased up to a mass loss of 50-60%, whereupon it decreased, while the amount of N (as a percentage of the original amount) remained unchanged until a mass loss of 50-60%, whereupon it decreased linearly. It seems that increasing soil temperatures may result in slightly higher rates of needle litter mass loss and consequent N release in northern peat than in southern peat. The faster decomposition in higher temperatures in the northern peat, together with the slightly higher maximum mass loss value, imply that with climatic warming, susceptibility of boreal peatlands for becoming sources of carbon to the atmosphere may increase towards north. (c) 2006 Elsevier SAS. All rights reserved.