机译:土地历史考试 荒漠化在华北地区
Department of Urban and Environmental Sciences Peking University Beijing 100871 P. R. China;
School of Humanities and Social Sciences Dalian University of Technology Dalian 116023 P. R. China;
School of Humanities and Social Sciences Dalian University of Technology Dalian 116023 P. R. China;
farming migrants; life style of Mongol; weather and land conditions; land desertification; Qing Dy-nasty;