Altered plant carbon partitioning enhanced forest ecosystem carbon storage after 25 years of nitrogen additions
Altered plant carbon partitioning enhanced forest ecosystem carbon storage after 25 years of nitrogen additions
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DOI：
10.1111/nph.17256
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发表时间：
2021-03-08
期刊：
影响因子：
9.4
通讯作者：
Peterjohn, William T.
中科院分区：
文献类型：
--
作者：
Eastman, Brooke A.;Adams, Mary B.;Peterjohn, William T.
美国东北部数十年的大气氮（N）沉降通过缓解氮限制而增强了这一全球重要的森林碳（C）汇。虽然许多氮肥施肥实验发现森林碳储量增加，但在生态系统规模上驱动这种反应的机制仍不确定。根据最优分配理论，增加氮素可用性可能会减少树木对根系和土壤共生体的地下碳投资。为了测试这一预测及其对土壤生物地球化学的影响，我们构建了一个长期的，全流域的N施肥研究在Fernow实验森林，西弗吉尼亚州，美国的C和N预算。氮肥增加C存储转移C分区远离地下组件和地上木质生物量生产。施肥也降低了氮素获取的碳成本，使植被中的碳固存量更大。尽管相同的细凋落物输入，C和N股票和C：N比的上层矿质土壤中的施肥分水岭，可能是由于减少分解的植物litter.By结合地上和地下的数据在流域尺度，本研究表明，植物C分配响应N的增加可能会导致更大的C存储在植被和土壤。
Decades of atmospheric nitrogen (N) deposition in the northeastern USA have enhanced this globally important forest carbon (C) sink by relieving N limitation. While many N fertilization experiments found increased forest C storage, the mechanisms driving this response at the ecosystem scale remain uncertain.Following the optimal allocation theory, augmented N availability may reduce belowground C investment by trees to roots and soil symbionts. To test this prediction and its implications on soil biogeochemistry, we constructed C and N budgets for a long-term, whole-watershed N fertilization study at the Fernow Experimental Forest, WV, USA.Nitrogen fertilization increased C storage by shifting C partitioning away from belowground components and towards aboveground woody biomass production. Fertilization also reduced the C cost of N acquisition, allowing for greater C sequestration in vegetation. Despite equal fine litter inputs, the C and N stocks and C : N ratio of the upper mineral soil were greater in the fertilized watershed, likely due to reduced decomposition of plant litter.By combining aboveground and belowground data at the watershed scale, this study demonstrates how plant C allocation responses to N additions may result in greater C storage in both vegetation and soil.