1. Adams, M. E., A study of the ecology ofAcacia mellifera, A. seyal andBalanitis aegyptiaca in relation to land clearing. J. Applied Ecol.4, 221–238 (1967).
2. Andrews, F. W., The vegetation of the Sudan.In J. D. Tothill (ed.), Agriculture in the Sudan. Oxford University Press (1948).
3. Bunting, A. H. and Lea, J. D., The soils and vegetation of the Fung, East Central Sudan. J. Ecol.50, 529–558 (1962).
4. Corby, H. D. L., The nutrition of legumes with particular reference to the Hight-Rainfall-Sandveld of Southern Rhodesia. Proceedings of the Fourth annual conference of the Professional Officers of the Department of Research and Specialist Servise (1959).
5. Dart, P. J. and Mercer, F. V., The effect of growth temperature, level of ammonium nitrate and light intensity on the growth and nodulation of Cowpea (Vigna sinensis Endl. ex Hassk.) Australian J. Agr. Research16, 34–45 (1965).