It is difficult to forecast the serious consequences of damage to soil health on plants, animals and human beings. Agricultural soils across the globe are affected by erosion, degradation, nutrient depletion, pollution, organic matter decline and faulty management practices. This has resulted into 'Plant nutrient disorders' due primarily to imbalances, interactions, deficiencies or toxicities of one or more plant nutrients. Quality of irrigation water and environmental stress has a profound influence on this process. The present book provides an insight into the reasons for occurrence of such nutrient disorders, methodologies to monitor soil, plant, water and environment and ways to diagnose the problem through analytical and instrumental techniques. Widespread occurrence of secondary and micronutrient deficiencies in soils have resulted into low uptake of these nutrient ions by plants with adverse impact on human and animal health. Continuous cropping without due care of efficient soil and water use, have resulted in poor crop performances with low yields in many areas. This book attempts to provide answers to some pertinent questions on the subject i.e. I. Why plant nutrient disorders occur? II. Whether these are site or crop specific? III. How best one can diagnose the problem, by adopting sound analytical techniques? IV. What are the major concerns? V. How best one can manage such disorders to sustain soil health for crop production? Implementing scientific soil management programme requires good team work among scientists, extension workers & field staff with governmental support and farmer's participation. It is hoped that this book written in a simple language will be very useful for the students and teachers of Agriculture, Horticulture, Forestry, Fisheries & allied disciplines.