Intensified plant N and C pool with more available nitrogen under experimental warming in an alpine meadow ecosystem |
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Authors: | Fei Peng Xian Xue Quangang You Manhou Xu Xiang Chen Jian Guo Tao Wang |
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Institution: | 1. key laboratory of desert and desertification, northwest institute of eco‐environment and resourceChinese Academy of Sciences;2. University of Chinese Academy of Sciences, Beijing, China;3. Taiyuan Normal University, Taiyuan, China |
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Abstract: | 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. |
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Keywords: | alpine meadow incubation infrared heater microbial biomass mineralization |
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