Soil Fertility Status of Cassava Fields in South Western Nigeria

Aims: Current information on nutrient status of south western Nigeria soils is needed to develop appropriate integrated nutrient management packages for sustainable cassava production within the area. This study is designed to provide information on fertility status of some soils of the area.

Study Design: A field survey.

Place and Duration of Study: The study was carried out in March 2009 within two agro ecological zones of Osun state, south western Nigeria.

Methodology: A field survey of 33 farmers’ fields in two agro ecological zones of Osun state namely; Iwo zone and Oshogbo zone was undertaken. Representative soil samples (0-20cm) were obtained from each field. Physical and chemical properties of soil samples were determined in the laboratory following established methods. Statistical analyses of soil data was carried out using appropriate techniques.

Results: The soils of the area are acidic (pH in water range: 5.4 -6.4) and 79% of the fields are deficient in soil organic matter. Nitrogen and phosphorus are below established critical limits for cassava production in half of the fields; exchangeable cations (calcium, magnesium and potassium) are present in adequate amounts in most soils. No significant differences (P .05) were observed between the zones for soil properties measured.

Conclusion: Farmer acceptable strategies for improving nutrients availability (particularly nitrogen and phosphorus), organic matter and overall soil health through use of fertilizers, organic materials and multipurpose legumes among other options are required for sustained cassava production.