All praises are to GOD, Lord of the Heavens and the Earth, for giving me the strength and capacity to undertake my study and for His help in all aspects of my life during my stay at university of Gondar. I am thankful to my parents for their love and moral and material support throughout my study.
I am deeply indebted to my major advisor, Doctor Assefa Tilahun (PhD) for his guidance and encouragement throughout my study. I am very much grateful to him for the constructive advices and comments, patience and providing me the freedom to think independently and reasonably throughout my proposal and thesis work. This thesis would not have been completed this way without his dedicated support.
I am also equally indebted to my co-advisor, Mr. Abebaw Abibo, for his invaluable guidance, advice and constructive comments throughout my work. I am also grateful for his suggestions, directions and tireless effort for the betterment of the work.
Besides, I wish to convey my heartfelt thanks to instructor Tadie Mirie for his multidimensional support and continuous encourage in my end over. I extend my profound appreciation to the farmers of Burji District for their hospitality willingly participated in the survey and spent many hours explaining their livelihoods.