Providing an overview of grassland nitrogen, this text incorporates information from crop science, soils and fertilizers, ruminant consumption and environmental aspects. The information is reviewed on the various transformations of nitrogen in temperate grassland systems. These include those taking place in plants and animals as well as those that take place in soils. The effects of soil, weather and management practices are discussed and considerable emphasis is placed on soil-plant-animal interactions. A second aim of the book is to describe the factors that influence the response of grassland to the application of fertilizer nitrogen, and how the optimum rate of application may be determined. In addition, nitrogen balances are described for different grassland systems, showing how the annual inputs and outputs vary greatly depending on sward type and management. The book should be interest to a wide readership, especially those engaged in research, teaching and advisory work, and students taking courses in agricultural and environmental sciences.