This open access book highlights concepts discussed at two international conferences that brought together world-renowned scientists to advance the science of potassium (K) recommendations for crops. There was general agreement that the potassium recommendations currently in general use are oversimplified, outdated, and jeopardize soil, plant, and human health. Accordingly, this book puts forward a significantly expanded K cycle that more accurately depicts K inputs, losses and transformations in soils. This new cycle serves as both the conceptual basis for the scientific discussions in this book and a framework upon which to build future improvements. Previously used approaches are critically reviewed and assessed, not only for their relevance to future enhancements, but also for their use as metrics of sustainability. An initial effort is made to link K nutrition in crops and K nutrition in humans. The book offers an invaluable asset for graduate students, educators, industry scientists, data scientists, and advanced agronomists.

The potassium solubilizing microorganisms (KSMs) are a rhizospheric microorganism which solubilizes the insoluble potassium (K) to soluble forms of K for plant growth and yield. K-solubilization is carried out by a large number of saprophytic bacteria (Bacillus mucilaginosus, B. edaphicus, B. circulans, Acidothiobacillus ferrooxidans, Paenibacillus spp.) and fungal strains (Aspergillus spp. and Aspergillus terreus). Major amounts of K containing minerals (muscovite, orthoclase, biotite, feldspar, illite, mica) are present in the soil as a fixed form which is not directly taken up by the plant. Nowadays most of the farmers use injudicious application of chemical fertilizers for achieving maximum productivity. However, the KSMs are most important microorganisms for solubilizing fixed form of K in soil system. The KSMs are an indigenous rhizospheric microorganism which show effective interaction between soil-plant systems. The main mechanism of KSMs is acidolysis, chelation, exchange reactions, complexolysis and production of organic acid. According to the literature, currently negligible use of potassium fertilizer as chemical form has been recorded in agriculture for enhancing crop yield. Most of the farmers use only nitrogen and phosphorus and not the K fertilizer due to unawareness that the problem of K deficiency occurs in rhizospheric soils. The K fertilizer is also costly as compared to other chemical fertilizers.

In-depth treatments of the soil quality concept, its history, and its applicability in research and in developed and developing societiesAll 18 chapters are written by well-established experts from Europe, North America and AustraliaSoil quality is a concept that allows soil functions to be related to specific purposes. Managing soil quality takes a management oriented approach by identifying key issues in soil quality and management options to enhance the sustainability of modern agriculture. Topics covered include major plant nutrients (N, P, K), soil acidity, soil organic matter, soil biodiversity, soil compaction, erosion, pesticides and urban waste.

This open access book highlights concepts discussed at two international conferences that brought together world-renowned scientists to advance the science of potassium (K) recommendations for crops. There was general agreement that the potassium recommendations currently in general use are oversimplified, outdated, and jeopardize soil, plant, and human health. Accordingly, this book puts forward a significantly expanded K cycle that more accurately depicts K inputs, losses and transformations in soils. This new cycle serves as both the conceptual basis for the scientific discussions in this book and a framework upon which to build future improvements. Previously used approaches are critically reviewed and assessed, not only for their relevance to future enhancements, but also for their use as metrics of sustainability. An initial effort is made to link K nutrition in crops and K nutrition in humans. The book offers an invaluable asset for graduate students, educators, industry scientists, data scientists, and advanced agronomists.

Potassium reserves in the world. Potassium fertlizer technology. Preparation of finished fertilizers containing potassium. Agronomic evaluatin of potassium polyphosphate and potassium calcium pyrophosphates as sources of potassium. Mineralogy of soil potassium. Role of potassium in photosynthesis and respiration. Effect of potassium on carbohydrate metabolism and translocation. The effect of potassium on the organic acid and Nonprotein nitrogen content of plant tissue. The effect of potassium and other univalent cations on the conformation of enzymes. Role of potassium in human and animal nutrition. The effects of potassium on disease resistance. Effect of potassium on Quality factors - fruits and vegetables. Soil factors affecting potassium availability. Mechanism of potassium absorption by plants. Exchangeable cations of plant roots and potassium absorption by the plant. Interaction of potassium and other ions. Plant factors affecting potassium availability and uptake. Potassium nutrition of tropical crops. Potassium nutrition of forage crops with perennials. Potassium nutrition of soybeans and corn. Potassium nutrition of tree crops. Potassium nutrition of vegetable crops.