Long-term agricultural field experiments, especially those that are 50 years or older, are relatively rare globally. A significant majority of them are also located in Europe and North America, with only a handful in Africa. One of the latter is the Pretoria long-term crop rotation and fertilization experiment that has been ongoing for over 60 years, hence the oldest of its kind in Africa. This book presents research results of a series of case studies conducted on the Pretoria long-term trial that comprehensively assessed long-term trends of soil quality and productivity in response to decades of crop rotation and fertilization practices. Important insights provided by the studies and their implications for agroecosystem sustainability and environmental quality are discussed in the book. Data contained in the book are strongly believed to provide a valuable referential base and contribute towards bridging the cross-regional information gap that exists between the African continent and the rest of the World. The book will be of interest to Soil and Environmental scientists, Agronomists, Extension workers, Farm managers, and others in the agricultural and fertilizer industry.