Potato is very sensitive to water and nitrogen applied during growth, affecting its profitability and impact on the environment. Recent scientific and technical breakthroughs enable us to make best use of water and nitrogen. This book shows how scientific knowledge works in practice, now and well into the new millennium. This systematic and comprehensive book on crop, soil and water technologies will assist producers to achieve optimal production with maximum benefit to themselves and to the environment. Crucial questions, such as: - Which sampling techniques of plants and soil are available and which should I use? - What do the data gathered mean and how do they assist me in water and nitrogen application? - Which decision support systems exist for rain-fed, irrigated, precision or organic farming? are answered. The book updates and interprets knowledge in a simple, easily understandable way. It is intended for farmers, farmers' consultants, researchers and decision makers and is also recommended for students in soil science and agronomy.