[1] China Agr Univ, Coll Resources & Environm Sci, 2 Yuan Ming Yuan West Rd, Beijing 100193, Peoples R China
[2] Minist Agr Field Sci Observat Hohhot, Key Ecol & Environm Expt Stn, Wuchuan 011705, Hohhot, Peoples R China
[3] Auburn Univ, Int Ctr Climate & Global Change Res, Auburn, AL 36849 USA
[4] Univ Kentucky, Coll Agr Ctr Food & Environm, Dept Plant & Soil Sci, Lexington, KY 40506 USA
[5] Chinese Acad Sci, State Key Lab Urban & Reg Ecol, Res Ctr Ecoenvironm Sci, Beijing 100085, Peoples R China