Assessment of Variation in Marginal Productivity Value of Water in Paddy Farming Systems in Times of Water Stress Onesmo Zakaria Sigalla 1,2,*, Reuben Mpuya Joseph Kadigi 3 and Juma Rajabu Selemani 1 1 Nelson Mandela–African Institution of Science and Technology, Nelson Mandera Road, Arusha P.O. Box 447, Tanzania 2 Water Right (T) Ltd., 109 Regent...Read More