Improving Potassium Recommendations for Agricultural Crops

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 There was general agreement that the potassium recommendations currently in general use are oversimplified, outdated, and jeopardize soil, plant, and human health.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 Cycle and Its Relationship to Recommendation Development.- Inputs: Potassium Sources for Agricultural Systems.- Outputs: Potassium Losses from Agricultural Systems.- Rhizosphere Processes and Root Traits Determining the Acquisition of Soil Potassium.- Potassium Use Efficiency of Plants.- Considerations for Unharvested Plant Potassium.- Considering Soil Potassium Pools with Dissimilar Plant Availability.- Using Soil Tests to Evaluate Plant Availability of Potassium in Soils.- Evaluating Plant Potassium Status.- How Closely is Potassium Mass Balance Related to Soil Test Changes.- Assessing Potassium Mass Balances in Different Countries and Scales.- Considerations for Selecting Potassium Placement Methods in Soil.- Timing Potassium Applications to Synchronize with Plant Demand.- Broadening the Objectives of Future Potassium Recommendations.- Improving Human Nutrition: A Critical Objective for Potassium Recommendations for Agricultural Crops.

Dr. T. Scott Murrell is Principal Scientist for the African Plant Nutrition Institute in Ben Guerir, Morocco. He is also an adjunct faculty member at both Purdue University and Mohammed VI Polytechnic University, and Fellow of the American Society of Agronomy. Previously, he was the Potassium Program Director for the International Plant Nutrition Institute after serving as the Northcentral Director of the Potash & Phosphate Institute. He has spent much of his career synthesizing scientific research to create educational products and programs that facilitate adoption of improved crop nutrient management practices. He has also designed multi-country experiments and the common research protocols and data standards needed to operationalize them. He received his Master of Science in Soil Fertility at Purdue University and his PhD in Soil Science at Texas A&M University.

Dr. Robert L. Mikkelsen is currently the Director of Communications for the African Plant Nutrition Institute.  Prior to this position, he served as Vice President and Director for the International Plant Nutrition Institute. Dr. Mikkelsen was previously a Professor of Soil Science at North Carolina State University and also worked as a Research Scientist with the Tennessee Valley Authority at the National Fertilizer Development Center.  Dr. Mikkelsen earned his B.S. degree from Brigham Young University and his Ph.D. degree in Soil Science from the University of California. Dr. Mikkelsen has received teaching awards and multiple professional awards from leading scientific organizations in soil science, agronomy, and horticulture.   

Gavin Sulewski is editor for the African Plant Nutrition Institute (APNI). Prior to joining APNI, he served as editor (2011-2019) for the International Plant Nutrition Institute (IPNI) and its quarterly magazine Better Crops with Plant Food. Previously he worked as an agronomist for both IPNI and its predecessor the Potash & Phosphate Institute (1996-2011). Within these institutes he has spent his career collaborating with agricultural scientists on the development of educational information and resources for the benefit of international agriculture. He obtained his B.Sc. in Agronomy and M.Sc. in Soil Science from the University of Saskatchewan, Canada. 

Dr Robert Norton holds agriculture and education qualifications and a PhD in crop agronomy. He managed and delivered research and education programs at Longerenong Agricultural College and The University of Melbourne (1981-2009), including large collaborative projects on crop adaptation, plant nutrition, climate change and grains agronomy. He was the Regional Director (Australia and New Zealand) for the International Plant Nutrition Institute (2009-2017) and now undertakes national and international consultancies in soil science and plant nutrition. He is the author of 150 refereed bookchapters, journal and conference papers as well as another 350 conference and extension articles.

Dr. Michael L. Thompson is a professor in the Agronomy Department at Iowa State University in Ames, Iowa, USA. With a BS from University of Illinois (1974) and a PhD from Ohio State University (1980), he has taught courses in soil genesis, clay mineralogy, micromorphology, soil-plant relationships, organic chemistry, soil and water chemistry, and ethics in science. His research program centers on soil processes that favor stability, transformations, and movement of nutrients, organic matter, and anthropogenic contaminants in soils. He is a fellow of the Soil Science Society of America, the American Society of Agronomy, and the American Association for the Advancement of Science.