1. Department of Soil Science, University of Nigeria, Nsukka, Nigeria;
2. Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana;
3. CSIR – Soil Research Institute, Kwadaso, Kumasi, Ghana;
4. College of Agriculture and Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana;
5. International Institute of Tropical Agriculture, Ibadan, Nigeria