@BOOK {ORTIZ:2002, title = {Trends and prospects for crop production in the African semi-arid tropics. ICRISAT Targeting Agricultural Research for Development in sub-Saharan Africa. 2 July 2002}, editor = {Ortiz, R. }, year = {2002}, publisher = {International Center for Research in Agroforestry (ICRAF)}, address = {Nairobi, Kenya}, }