Intensified plant N and C pool with more available nitrogen under experimental warming in an alpine meadow ecosystem

• Published in: Ecology and Evolution
• Main Authors: Peng, Fei, Xue, Xian, You, Quangang, Xu, Manhou, Chen, Xiang, Guo, Jian, Wang, Tao
• Format: Text
• Language: English
• Published: John Wiley and Sons Inc. 2016
• Subjects: Original Research; permafrost
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5167058/; https://doi.org/10.1002/ece3.2583

Nitrogen (N) availability is projected to increase in a warming climate. But whether the more available N is immobilized by microbes (thus stimulates soil carbon (C) decomposition), or is absorbed by plants (thus intensifies C uptake) remains unknown in the alpine meadow ecosystem. Infrared heaters were used to simulate climate warming with a paired experimental design. Soil ammonification, nitrification, and net mineralization were obtained by in situ incubation in a permafrost region of the Qinghai‐Tibet Plateau (QTP). Available N significantly increased due to the stimulation of net nitrification and mineralization in 0–30 cm soil layer. Microbes immobilized N in the end of growing season in both warming and control plots. The magnitude of immobilized N was lower in the warming plots. The root N concentration significantly reduced, but root N pool intensified due to the significant increase in root biomass in the warming treatment. Our results suggest that a warming‐induced increase in biomass is the major N sink and will continue to stimulate plant growth until plant N saturation, which could sustain the positive warming effect on ecosystem productivity.