Growth and yield response of cowpea (Vigna unguiculata [L] Walp) to NPK fertilizer and rhizobia inoculation in the Guinea and Sudan Savanna Zones of Ghana

A thesis presented to the Department of Crop and Soil Sciences, Faculty of Agriculture, College of Agriculture and Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi Ghana, in partial fulfilment of the requirements for the award of degree of Doctor of Philosophy in Soil Science, 2014