Mineral Nitrogen in the Plant-Soil System provides integrated accounts of the transformations and fate of mineral nitrogen in the plant-soil system. This book emphasizes the understanding of various processes and the factors that affect these processes. It also focuses on the role of biological nitrogen fixation in nitrogen cycling in natural and agricultural systems. The book is divided into seven major chapters and each chapter is further subdivided into various subtopics. The first chapter introduces and outlines the origin, distribution, and cycling of nitrogen in natural and agricultural terrestrial ecosystems. Chapter 2 focuses on the processes of decomposition and mineralization-immobilization turnover. The processes of nitrification are discussed in detail in Chapter 3. The following four chapters discuss topics of retention and movement of nitrogen in soils; gaseous losses of nitrogen; uptake and assimilation of mineral nitrogen by plants; and lastly, the use of nitrogen in agronomic practice. The book will be invaluable to graduate students and researchers in the field of agriculture. This will also cater other parties interested, such as agronomists, soil scientists, plant physiologists, horticulturists, and foresters.