ADEMOLA BRAIMOH, PAUL L. G. VLEK
University of Bonn, Department of Ecology and Natural Resource Management, Center for Development Research (ZEF), Germany
The Northern region of Ghana is the largest administrative region in Ghana. It occupies over 40% of mainland Ghana and has a population of about 1.8 million. About 80% of the people depend on farming for their livelihood, with maize as the most important cultivated food crop. The Northern region of Ghana was once the leading producer of maize in the whole of Ghana, but maize yields have consistently declined in the last few years. This phenomenon constitutes a threat to food security and calls for efforts to explain the downward trend and make recommendations for improvement. The objectives of this study were to evaluate the soils of an area in Northern Ghana for maize on the one hand, and identify factors affecting maize yield on the other. A novel technique that combines soil survey with socioeconomic analyses was adopted in the study. Soil samples were collected within different land-cover types and analysed in the laboratory for chemical and physical properties. A soil quality index was generated for each sampling locations using fuzzy set technique, whereas spatial interpolation of soil quality was carried out by kriging. A structured questionnaire was administered to 237 households in 20 villages to elicit information on factors affecting crop yield. Relationships between maize yield and variables presumed to influence yield were determined using bivariate and linear multiple regressions. The results indicated that soil quality and fertiliser use are the most important factors affecting maize yield. Soil organic C, ECEC and clay were identified as the major soil-related constraints to yield. Other less important variables are related to demography and commercial factors. It is recommended that emphasis should be placed on soil management techniques that conserve soil organic matter and enhance the nutrient and water holding capacity of the soils. Policies that would enhance commercialisation agriculture are also required in Northern Ghana.
Keywords: Food security, fuzzy set, kriging, maize yield, soil organic C, soil quality