Response of soil surface CO2 flux in a boreal forest to ecosystem warming
Response of soil surface CO2 flux in a boreal forest to ecosystem warming
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DOI：
10.1111/j.1365-2486.2007.01508.x
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发表时间：
2008-04-01
影响因子：
11.6
通讯作者：
Van Herk, Ingrid
中科院分区：
文献类型：
--
作者：
Bronson, Dustin R.;Gower, Stith T.;Van Herk, Ingrid
土壤表面二氧化碳（CO2）通量（R-S）测量了2年的北方土壤和空气变暖实验地点附近的汤普森，MB，加拿大。实验设计是完全随机区组设计，由四个重复区组组成，每个区组包含15 m x 15 m对照和加热区。黑云杉[Picea mariana（Mill.）林下优势种为柳叶菜。对于每个加热的地块，使用填充水的聚乙烯管内的电缆将土壤温度保持在对照土壤温度以上（类似于5 ℃）。将位于土壤升温区中心的直径为7.3 m的室内空气加热至高于对照环境空气温度5 ℃，以测试仅土壤升温和土壤+空气升温。土壤表层CO2通量（R-S）与10 cm土壤温度呈极显著正相关（P < 0.0001）。2004年，土壤升温处理的土壤表面CO2通量（R-S）比对照增加了24%，但在2005年仅增加了11%，而土壤+空气升温处理的R-S比对照减少了31%，2005年减少了23%。2004年，加热处理的活细根质量（直径< 2 mm）低于对照处理，2005年在统计学上低于对照处理（P < 0.01）。两种加热处理之间相似的根质量表明，不同的加热方法（仅土壤与土壤+空气加热）可以影响分解速率。
Soil surface carbon dioxide (CO2) flux (R-S) was measured for 2 years at the Boreal Soil and Air Warming Experiment site near Thompson, MB, Canada. The experimental design was a complete random block design that consisted of four replicate blocks, with each block containing a 15 m x 15 m control and heated plot. Black spruce [Picea mariana (Mill.) BSP] was the overstory species and Epilobium angustifolium was the dominant understory. Soil temperature was maintained (similar to 5 degrees C) above the control soil temperature using electric cables inside water filled polyethylene tubing for each heated plot. Air inside a 7.3-m-diameter chamber, centered in the soil warming plot, contained approximately nine black spruce trees was heated similar to 5 degrees C above control ambient air temperature allowing for the testing of soil-only warming and soil+air warming. Soil surface CO2 flux (R-S) was positively correlated (P < 0.0001) to soil temperature at 10 cm depth. Soil surface CO2 flux (R-S) was 24% greater in the soil-only warming than the control in 2004, but was only 11% greater in 2005, while R-S in the soil+air warming treatments was 31% less than the control in 2004 and 23% less in 2005. Live fine root mass (< 2 mm diameter) was less in the heated than control treatments in 2004 and statistically less (P < 0.01) in 2005. Similar root mass between the two heated treatments suggests that different heating methods (soil-only vs. soil+air warming) can affect the rate of decomposition.