EFFECTS OF SOIL AND WATER CONSERVATION TECHNIQUES ON SOIL PRODUCTIVITY AND BEAN GRAIN YIELD IN NYAMASHEKE DISTRICT, RWANDA Joas Tugizimana (BSc in Agricultural Engineering) A147EA/22341/2011 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science (Land and Water Management) in the School of Agriculture and Enterprise Development, Kenyatta University OCTOBER, 2015