Methane flux characteristics in forest soils under an East Asian monsoon climate
Methane flux characteristics in forest soils under an East Asian monsoon climate
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DOI：
10.1016/j.soilbio.2008.12.003
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发表时间：
2009-02
影响因子：
9.7
通讯作者：
Masayuki Itoh;N. Ohte;K. Koba
中科院分区：
文献类型：
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作者：
Masayuki Itoh;N. Ohte;K. Koba
与夏季干旱的地区相比，在夏季降水较多的地区，例如东亚季风气候下，土壤对甲烷(CH4)的吸收可能受到更大的抑制。为了确定降水模式如何影响温带森林土壤中CH4通量的季节和空间变化，在日本中部一片柏树林的山坡上对CH4通量和选定的环境变量进行了测量。坡面上部和中部全年都有CH4吸收，吸收速率随土壤温度的升高略有增加，随土壤水分的增加而降低。利用坡面中部和上部的数据预测的CH4通量分别为−1.12~−0.83 kg·CH4ha−1y−1(即土壤对CH4的吸收)和−2.30~−2.04 kg·CH4ha−1y−1。相比之下，在靠近溪流湿地的相对潮湿的斜坡下部，在多雨的夏季观察到大量的CH4排放(>；2 mg-CH4m−1D−1)。在这片湿润的地块里，土壤在雨年起到了每年净甲烷源的作用。因此，随着土壤水分条件和土壤温度的变化，坡面下部CH4通量的变化与坡面上部和中部的变化形成鲜明对比。旱年预测的CH4通量为0.45 kg·−-CH4ha−1y−1，多雨年为1.80 kg·CH4ha−1y−1。我们的结果表明，考虑整个流域的土壤水分状况对于估计整个森林流域的CH4收支是很重要的，特别是在夏季潮湿的地区。
Methane (CH4) uptake by soil can possibly be suppressed more in regions with heavy summer precipitation, such as those under the East Asian monsoon climate, as compared to that in regions with a dry summer. In order to determine how precipitation patterns affect seasonal and spatial variations in CH4fluxes in temperate forest soils, such fluxes and selected environmental variables were measured on different parts of a hill slope in a cypress forest in central Japan. On the upper and middle parts of the slope, CH4uptake was observed throughout the year, and the uptake rates increased slightly with soil temperature and decreased with soil water content. The CH4flux predicted using data for the middle and upper parts of the slope ranged from −1.12 to −0.83kg-CH4ha−1y−1(i.e. CH4uptake by soil) and from −2.30 to −2.04kg-CH4ha−1y−1, respectively. In contrast, in the relatively wet lower part of the slope near an in-stream wetland, large CH4emissions (>2mg-CH4m−1d−1) were observed during the rainy summer. In this wetter plot, the soil functioned as a net annual CH4source in a rainy year. Hence the variation in CH4flux with a change in soil water conditions and soil temperature on the lower part of the slope contrasted to that on the upper and middle parts of the slope. The predicted CH4flux for this lower plot ranged from −0.45kg-CH4ha−1y−1in a dry year to 1.80kg-CH4ha−1y−1in a rainy year. Our results suggest that consideration of the soil water conditions across a watershed is important for estimating the CH4budgets for entire forest watershed, particularly in regions subject to a wet summer.