Effects of an experimental drought and recovery on soil emissions of carbon dioxide, methane, nitrous oxide, and nitric oxide in a moist tropical forest
Effects of an experimental drought and recovery on soil emissions of carbon dioxide, methane, nitrous oxide, and nitric oxide in a moist tropical forest
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DOI：
10.1111/j.1365-2486.2008.01694.x
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发表时间：
2008-11-01
影响因子：
11.6
通讯作者：
Brando, Paulo M.
中科院分区：
文献类型：
--
作者：
Davidson, Eric A.;Nepstad, Daniel C.;Brando, Paulo M.
亚马逊流域的降水变化导致区域森林砍伐，全球变暖和厄尔尼诺事件可能会影响二氧化碳（CO2），甲烷（CH4），一氧化二氮（N2O）和一氧化氮（NO）从土壤中的排放。土壤中重要辐射气体排放量的变化可能对区域和全球气候产生反馈影响。在这里，我们报告的最终结果的5年，大规模（1公顷）穿透排除实验，随后1年的恢复与自然穿透，在一个成熟的万年青林附近的桑塔雷姆，巴西进行。排除操纵降低了年N2O排放量在四个五年的治疗（自然干旱的一年是例外），然后恢复在第一年干旱治疗后停止。同样，大气CH4的消耗增加干旱处理下，除了在一个自然干旱的年份，它也恢复到预处理值在第一年，自然穿透允许回的情节。在前3个处理年中没有检测到NO排放的处理效果，但在自然干旱期间排除图的极端干燥条件下，NO排放在第四年增加。令人惊讶的是，在任何一年都没有对土壤CO2排放的处理效果。干旱处理引起了显着的树木死亡率和减少C分配到茎，但分配到叶和根的C的影响较小。两者合计，这些结果表明，在这6年的时间内，穿透排除对土壤过程的主导作用是土壤通气条件，短暂影响甲烷，N2O，NO的生产和消费。
Changes in precipitation in the Amazon Basin resulting from regional deforestation, global warming, and El Nino events may affect emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) from soils. Changes in soil emissions of radiatively important gases could have feedback implications for regional and global climate. Here, we report the final results of a 5-year, large-scale (1 ha) throughfall exclusion experiment, followed by 1 year of recovery with natural throughfall, conducted in a mature evergreen forest near Santarem, Brazil. The exclusion manipulation lowered annual N2O emissions in four out of five treatment years (a natural drought year being the exception), and then recovered during the first year after the drought treatment stopped. Similarly, consumption of atmospheric CH4 increased under drought treatment, except during a natural drought year, and it also recovered to pretreatment values during the first year that natural throughfall was permitted back on the plot. No treatment effect was detected for NO emissions during the first 3 treatment years, but NO emissions increased in the fourth year under the extremely dry conditions of the exclusion plot during a natural drought. Surprisingly, there was no treatment effect on soil CO2 efflux in any year. The drought treatment provoked significant tree mortality and reduced the allocation of C to stems, but allocation of C to foliage and roots were less affected. Taken together, these results suggest that the dominant effect of throughfall exclusion on soil processes during this 6-year period was on soil aeration conditions that transiently affected CH4, N2O, and NO production and consumption.