1 Collaborative Innovation Center for Modern Crop Production co-sponsored by Province and Ministry, College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China
2 Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in northwestern China, Key Lab. of Restoration and Reconstruction of Degraded Ecosystems in northwestern China of Ministry of Education, School of Ecology and Environment, Ningxia University, Yinchuan 750021, China
3 State Key Laboratory of Herbage Improvement and Grassland Agroecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu 730000, China
4 Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Göttingen 37077, Germany
5 Peoples Friendship University of Russia (RUDN University), Moscow 117198, Russia