Altered plant carbon partitioning enhanced forest ecosystem carbon storage after 25 years of nitrogen additions

BA Eastman, MB Adams, ER Brzostek… - New …, 2021 - Wiley Online Library
New Phytologist, 2021Wiley Online Library
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 …
Summary
  • 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.
Wiley Online Library
以上显示的是最相近的搜索结果。 查看全部搜索结果