Drying and wetting of Mediterranean soils stimulates decomposition and carbon dioxide emission: the "Birch effect"
Drying and wetting of Mediterranean soils stimulates decomposition and carbon dioxide emission: the "Birch effect"
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DOI：
10.1093/treephys/27.7.929
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发表时间：
2007-07-01
期刊：
影响因子：
4
通讯作者：
Valentini, Riccardo
中科院分区：
文献类型：
--
作者：
Jarvis, Paul;Rey, Ana;Valentini, Riccardo
最近用涡度协方差法对欧洲地中海地区森林的净碳交换进行了观测，重新引起了人们对20世纪50年代和60年代由H. F.伯奇效应，现在常被称为“伯奇效应”。“当土壤在夏季由于缺乏雨水而变得干燥时，就像地中海气候地区常见的那样，或者在实验室中在受控条件下干燥，然后通过降水或灌溉重新湿润，就会出现分解，矿化和释放无机氮和二氧化碳的爆发。在南欧地中海气候的森林中，这种效应已经分别在林分和小地块尺度上用涡度协方差技术和土壤呼吸室观察到。在Birch的早期工作之后，在受控温度和含水量下对土壤进行的实验室培养已被用于表征干燥土壤再润湿后的CO2释放。一个简单的经验模型的基础上，实验室培养表明，一年的矿化碳量可以预测土壤温度和降水制度，碳损失的CO2考虑在内。我们表明，土壤复湿后返回大气的碳量可以显着减少地中海森林的年度净碳收益。
Observations on the net carbon exchange of forests in the European Mediterranean region, measured recently by the eddy covariance method, have revived interest in a phenomenon first characterized on agricultural and forest soils in East Africa in the 1950s and 1960s by H. F. Birch and now often referred to as the "Birch effect." When soils become dry during summer because of lack of rain, as is common in regions with Mediterranean climate, or are dried in the laboratory in controlled conditions, and are then rewetted by precipitation or irrigation, there is a burst of decomposition, mineralization and release of inorganic nitrogen and CO2. In forests in Mediterranean climates in southern Europe, this effect has been observed with eddy covariance techniques and soil respiration chambers at the stand and small plot scales, respectively. Following the early work of Birch, laboratory incubations of soils at controlled temperatures and water contents have been used to characterize CO2 release following the rewetting of dry soils. A simple empirical model based on laboratory incubations demonstrates that the amount of carbon mineralized over one year can be predicted from soil temperature and precipitation regime, provided that carbon lost as CO2 is taken into account. We show that the amount of carbon returned to the atmosphere following soil rewetting can reduce significantly the annual net carbon gain by Mediterranean forests.