Soil suitability evaluation for production of improved Cassava ( Manihot esculenta ) varieties in Kwara State, Nigeria: A GIS-Based and Multi-Criteria analysis

A study was carried out to determine the adaptability of improved cassava varieties in various locations in the eastern part of Kwara State, Nigeria. Four improved cassava varieties and one local variety were investigated in the University of Ilorin (Unilorin) farm and at the Offa area of Kwara State. Physico-chemical properties were used to calculate soil suitability index using Multi-Criteria Analysis (MCA). Soil suitability and productivity index were interpolated over the Eastern part of Kwara State using a kriging method in SUFER 8.01, GIS software. The results showed that whereas Unilorin had better physical soil properties, the Offa area, on the other hand, showed better chemical soil properties. Soil suitability for cassava production was better in Offa (57.2%) than in Unilorin (37.6%). The spatial analysis showed increasing soil suitability from the northern to the southern regions with the highest suitability in Oyun, Offa and Irepodun districts. The improved cassava varieties produced an average yield of 19-20 tons/ha compared to 5.3-6.5 tons/ha of the local variety. The spatial analysis showed decreasing cassava productivity from the western to the eastern regions with the highest productivity in the Asa, Oyun, Offa and Ilorin districts. It is recommended that the cultivation of these improved cassava varieties be accompanied with good soil fertility management practices like organic fertilizer application combined with inorganic fertilizer microdosing technology in the Eastern Districts of the Kwara State, especially at Moro, Edu, Ifelodun and Isin districts.