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Supplemental Information

Additional Information

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Ping P Zhang conceived and designed the experiments, performed the experiments, analyzed the data, prepared figures and/or tables, approved the final draft.

Yan L Zhang performed the experiments.

Jun C Jia performed the experiments.

Yong X Cui performed the experiments.

Xia Wang performed the experiments.

Xing C Zhang conceived and designed the experiments.

Yun Q Wang conceived and designed the experiments, authored or reviewed drafts of the paper, approved the final draft.

Field Study Permissions

The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):

Field experiments were approved by the SHENHUA GROUP ZHUNGEER ENERGY CO.,LTD.

Data Deposition

The following information was supplied regarding data availability:

The raw data is provided in the Supplemental Files.


This study was financially supported by the National Natural Science Foundation of China (no. 41501236) and the Chinese Academy of Sciences (KZCX2-XB3-13-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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