Warming Mitigates the Impacts of Degradation on Nitrogen Allocation between Soil Microbes and Plants in Alpine Meadow
Zhe Pang,
Guoqi Wen,
Lili Jiang,
Xiaowei Nie,
Zongsong Wang,
Rui Pang,
Wenjing Liu,
Meirong Chen,
Weiwai Zhao,
Li Tang,
Biao Zhang,
Linfeng Li,
Shutong Zhou,
Xingliang Xu,
Yanbin Hao,
Xiaoyong Cui,
Shiping Wang,
Yanfen Wang
Affiliations
Zhe Pang
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Guoqi Wen
Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6, Canada
Lili Jiang
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Xiaowei Nie
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Zongsong Wang
College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Rui Pang
Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China
Wenjing Liu
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Meirong Chen
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Weiwai Zhao
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Li Tang
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Biao Zhang
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Linfeng Li
Forestry College, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Shutong Zhou
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
Xingliang Xu
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Yanbin Hao
College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Xiaoyong Cui
College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Shiping Wang
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Yanfen Wang
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
In alpine meadows, plants and soil microbes typically engage in competition for nitrogen (N) under N-deficient conditions. However, the acquisition and distribution of N among soil microbes and plants under alpine meadow degradation and climate warming induced by global climate change are still uncharacterized. In this study, we isotope labeled inorganic (NH4+-15N, NO3−-15N) and organic (glycine-15N) N in both degraded and non-degraded plots by using open-top chambers (OTC) to mimic increasing air temperatures. After 6 h, the 15N contents in soil microbes and plants were measured to investigate the effects of degradation and rising air temperature on N allocations in the ecosystems studied. Results showed that alpine meadow degradation significantly reduced soil microbial N accumulation by 52% compared to those in non-degraded plots. In non-degraded plots, warming significantly lowered the organic N levels of soil microbes by 49%, whereas in degraded ones, it reduced both NH4+-15N and NO3−-15N recovery by 80% and 45% on average but increased glycine-15N recovery by 653%. Meanwhile, warming decreased the plant recovery of NH4+-15N and NO3−-15N by 75% and 45% but increased the recovery of glycine-15N by 45% in non-degraded plots. Conversely, in degraded plots, warming markedly lowered NH4+-15N recovery by 40% but increased glycine-15N recovery by 114%. Warming mitigates the effects of alpine meadow degradation on nitrogen allocation among soil microbes and plants. In unwarmed plots, degradation significantly elevated the total 15N recovery ratio of soil microbes to plants by 60%. However, in warmed plots, the impact of degradation on this ratio was reduced. The responses of the 15N recovery ratio of soil microbes and plants to rising temperatures were closely related to alpine meadow quality. In non-degraded areas, warming enhanced the recovery ratio for NH4+-15N by 165% but reduced it for glycine-15N by 66%. Conversely, in degraded plots, warming decreased the recovery ratio for NH4+-15N by 66% but increased it for glycine-15N by 232%. This indicates that warming can increase carbon limitation for soil microbes in degraded alpine meadows, and the restoration of degraded alpine meadows should prioritize restoring carbon accumulation.
