College of Land Science and Technology China Agricultural University/Key Laboratory of Remote Sensing for Agri-hazards Ministry of Agriculture and Rural Affairs/Key Laboratory for Agricultural Land Quality Ministry of Natural Resources Beijing 100083 P.R.China;
College of Information & Electrical Engineering China Agricultural University Beijing 100083 P.R.China;
Department of Geography University College London London WC1E 6BT UK;
Department of Agro-meteorology and Geo-informatics Magbosi Land Water and Environment Research Centre (MLWERC) Sierra Leone Agricultural Research Institute (SLARI) Freetown PMB 1313 Sierra Leone;