The mission of the International Fertilizer Development Center is to increase food production through the improvement of fertilizers and fertilizer practices for the developing countries with special emphasis on tropical and subtropical agriculture. The principal aim is to ensure that fertilizer technology is not a limiting factor to food production in those regions. Although the full extent to which deficiency of micronutrients hampers food production is yet un known, there is ample evidence that problem areas exist and more will be identified as crop production is intensified and marginal lands are exploited. Therefore, it seems fully appropriate at this time that IFDC, as an international organization, take a leadership role in developing micronutrient fertilizer technology appropriate for the tropics and subtropics. The gravity of micronutrient deficiency as a limiting factor to crop pro duction varies from crop to crop and from soil to soil. The effects may range from slight yield reductions to complete crop failure. While the economic impact of omitting micronutrients in seriously affected areas (e.g., Zn in Brazilian Cerrado) is convincing, it is difficult to estimate the yearly loss in crop production due to unsuspected micronutrient deficiency. Active soil and crop testing programs in regions with advanced agricultural systems are aimed at recognizing micronutrients as a limiting plant nutrient in time to allow corrective measures and prevent yield loss. Successful micronutrient monitoring systems are generally limited to developed economies or to developing economies producing export cash crops.

A deficiency of one or more of the eight plant micronutrients (boron, chlorine, copper, iron, manganese, molybdenum, nickel and zinc) will adversely affect both the yield and quality of crops. Micronutrient deficiencies in crops occur in many parts of the world, at various scales (from one to millions of hectares), but differences in soil conditions, climate, crop genotypes and management, result in marked variations in their occurrence. The causes, effects and alleviation of micronutrient deficiencies in crops in: Australia, India, China, Turkey, the Near East, Africa, Europe, South America and the United States of America, are covered, and these are representative of most of the different conditions under which crops are grown anywhere in the world. Links between low contents of iodine, iron and zinc (human micronutrients) in staple grains and the incidence of human health problems are discussed, together with the ways in which the micronutrient content of food crops can be increased and their bioavailability to humans improved. Detailed treatment of topics, such as: soil types associated with deficiencies, soil testing and plant analysis, field experiments, innovative treatments, micronutrients in the subsoil, nutrient interactions, effects of changing cropping systems, micronutrient budgets and hidden deficiencies in various chapters provides depth to the broad coverage of the book. This book provides a valuable guide to the requirements of crops for plant micronutrients and the causes, occurrence and treatment of deficiencies. It is essential reading for many agronomy, plant nutrition and agricultural extension professionals.

Plants require essential nutrients (macronutrients and micronutrients) for normal functioning. Sufficiency range is the levels of nutrients necessary to meet the plant’s needs for optimal growth. This range depends on individual plant species and the particular nutrient. Nutrient levels outside of a plant’s sufficiency range cause overall crop growth and health to decline, due either to deficiency or toxicity from over-accumulation. Apart from micronutrients (B, Cl, Mn, Fe, Zn, Cu and Mo), Aluminum (Al), cerium (Ce), cobalt (Co), iodine (I), lanthanum (La), sodium (Na), selenium (Se), silicon (Si), titanium (Ti), and vanadium (V) are emerging as novel biostimulants that may enhance crop productivity and nutritional quality. These beneficial elements are not "essential" but when supplied at low dosages, they augment plant growth, development, and yield by stimulating specific molecular, biochemical, and physiological pathways in responses to challenging environments. The book is the first reference volume that approaches plant micronutrient management with the latest biotechnological and omics tools. Expertly curated chapters highlight working solutions as well as open problems and future challenges in plant micronutrient deficiency or toxicity. We believe this book will introduce readers to state-of-the-art developments and research trends in this field.