Add to ORKG/J P.5 The author wishes to acknowledge his special appreciation for the patience, guidance, attentiveness, and experience conveyed to him by his major advisors. Dr. John Borrelli and Professor Marvin J. Dvoracek. Completion of this dissertation would not have been possible without their assistance. Sincere gratitude is expressed to Dr. Richard Zartman, Dr. Priyantha Jaywickrama, and Dr. John Day for their assistance and for serving on the graduate committee. The author expresses his gratitude to the Institutional Development for Agricultural Training (IDAT) Project for providing the financial support for this study. Last but not least, the author wishes to thank his wife Laura, and his children Annabell, Harrison and Esther for their patie...