Download or read book Factors Affecting the Release of Soil Potassium to Exchangeable Form on Drying written by Harry Mikio Kunishi and published by . This book was released on 1963 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Affecting the Availability of Potassium Through Fixation and Release in Soils of Diverse Mineralogical Composition written by Gordon Lawrence Rees and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The management of soil potassium is complicated by sorption and release of K by soil minerals, with fixation of K by vermiculite removing it from the pool of readily-available exchangeable K. Several laboratory methods have been developed to characterize different pools of soil potassium, including ammonium acetate extraction of exchangeable K (XK), sodium tetraphenylboron extraction of exchangeable and some nonexchangeable K (TPB-K), and a method to estimate the potential of soils to fix K (Kfix). In order to understand the relationship of these methods to each other and to K uptake by plants, we undertook a series of experiments to evaluate the effect of K concentration, incubation time, soil moisture content, and mineralogy on soil K pools. Additions of K equal to initially measured Kfix values only partially reduced K fixation, and increased XK and TPB-K by less than the amount of K added, indicating that some K was fixed strongly enough to be removed from the nominally plant-available pool. Duration of incubation with K from 1 to 16 days did not significantly impact K fixation or availability as measured by these methods, indicating that fixation reactions took place within the first 24 hours. Incremental additions of potassium up to an amount equal to the cation exchange capacity resulted in increasing amounts of K fixed. For some soils, a plateau was reached indicating a maximum level of K fixation, but for other soils it is unclear if a maximum was achieved. Recovery of K by the TPB-K method was roughly twice as efficient as by the XK method. Approximately 50% of fixed K was plant-available nonexchangeable K (PANK), meaning it was recovered by the TPB-K method but not by the XK method. A single air-drying event, relative to soils maintained at field-moist water content, resulted in an increase in Kfix for all K-fixing soils by an average of 55 mg kg−1, but the change in Kfix for non-K-fixing soils was not consistent. The change in Kfix was not correlated with XK values. Changes in XK with drying were less than 20 mg kg−1 for most samples, with XK increasing for most K-fixing and low-XK soils, with less consistency for high-XK soils. Multiple cycles of wetting and drying did not result in further changes in soil K measurements. In a greenhouse pot study, K uptake by annual ryegrass (Lolium multiflorum) was best correlated with TPB-K (r=0.8966), and yield was best correlated with total K by aqua regia digestion (r=0.7465) followed by TPB-K (r=0.6692). The critical value for yield response determined by the TPB-K method was most successful in predicting significant responses to increased K rates. The XK method also performed well in this respect. K fixation by one soil resulted in reduced uptake of K, and in yield responses to higher K rates than predicted by critical values for all methods. For other soils, the effect of K fixation potential was unclear. Atomic force microscopy of clay grains from selected K-fixing soils and standard clays revealed complex surface morphology for most soils which made it impossible to delineate changes in layer spacing with K sorption or release. Nearly-flat surfaces and stacks of relatively few layers in smectite clays were more conducive to this analysis. For both montmorillonite and beidellite standards, layers collapsed with displacement of Na+ by K+, and re-expanded after extraction with a TPB solution. No zones of preferential K fixation or release were observed.
Download or read book Improving Potassium Recommendations for Agricultural Crops written by T. Scott Murrell and published by Springer. This book was released on 2022 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Factors Influencing the Levels of Exchangeable Potassium in Gilpin and Cookport Soils written by W. B. Barrett and published by . This book was released on 1973 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geological Survey Bulletin written by and published by . This book was released on 1963 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Movement of Potassium in the Soil written by Marvin Dean Kauffman and published by . This book was released on 1965 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Potassium Release in Soils as Affected by Drying written by Thomas Edward Bates and published by . This book was released on 1961 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book TT written by Clearinghouse for Federal Scientific and Technical Information (U.S.) and published by . This book was released on 1968 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Translations of scientific and technical monographs and articles.
Download or read book Effect of Exchangeable Potassium Level and Drying on Release and Fixation of Potassium by Selected Kentucky Soils written by Robert H. Dowdy and published by . This book was released on 1961 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts written by and published by . This book was released on 1963-05 with total page 1756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstracts of dissertations and monographs in microform.
Download or read book Agronomy Abstracts written by and published by . This book was released on 1954 with total page 968 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes abstracts of the annual meetings of the American Society of Agronomy; Soil Science Society of America; Crop Science Society of America ( - of its Agronomic Education Division).
Download or read book The Effect of Drying on Exchangeable Potassium in Soils from Illinois and Kansas written by Robert Arthur Bohannon and published by . This book was released on 1957 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fixation and Release of Potassium in Several Eastern Oklahoma Soils written by John J. Micka and published by . This book was released on 1957 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstracts of Recent Published Material on Soil and Water Conservation written by and published by . This book was released on 1962 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstracts for Dec. 1954- issued in the Agricultural Research Service's series ARS-41.
Download or read book Release of Nonexchangeable Soil Potassium on Drying written by Ralph E. Luebs and published by . This book was released on 1954 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Changes in Exchangeable Potassium with Drying in Illinois Soils written by Om Autar Goel and published by . This book was released on 1955 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Soil Science written by and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world needs for food and fiber continue to increase. Population growth in the developing countries peaked at 2. 4 percent a year in 1965 and has fallen to about 2. I percent. However, in many developing countries almost half the people are under 15 years of age, poised to enter their productive and reproductive years. The challenges to produce enough food for this growing population will remain great. Even more challenging is growing the food in the areas of greatest need. Presently the world has great surpluses of food and fiber in some areas while there are devastating deficiencies in other areas. Economic conditions and the lack of suitable infrastructure for distribution all too often limit the alleviation of hunger even when there are adequate supplies, sometimes even within the country itself. World hunger can only be solved in the long run by increasing crop production in the areas where the population is growing most rapidly. This will require increased efforts of both the developed and developing countries. Much of the technology that is so successful for crop production in the developed countries cannot be utilized directly in the developing countries. Many of the principles, however, can and must be adapted to the conditions, both physical and economic, of the developing countries. This series, Advances in Soil Science.
