Acknowledgements
This study was funded by the National Key Research and Development Program of China (No. 2017YFC0506503; No.2017YF0504600), National Natural Science Foundation of China (No.41771318), Scientific and Technologial Innovation Programs of Higher Education Institutions of Shanxi (No.2020L0680). We thank the Ansai Agro-Ecological Research Station on the Loess Plateau for providing experimental site and research support.