Download or read book Characterization of the Phosphorus Supplying Capacity of Soils by Desorption Q I Relationships and Kinetics written by Klaus Peter Raven and published by . This book was released on 1992 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterizing Phosphate Desorption Kinetics from Soil written by Abi Taddesse Mengesha and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many agricultural fields that have received long-term applications of P often contain levels of P exceeding those required for optimal crop production. Knowledge of the effect of the P remaining in the soil (residual effect) is of great importance for fertilization management. In order to characterize P forms in soils, a wide variety of methods have been proposed. The use of dialysis membrane tubes filled with hydrous ferric oxide (DMT-HFO) has recently been reported as an effective way to characterize P desorption over a long-term in laboratoty studies. However, there is little information on the relationship between kinetics of P release using this new method and plant P uptake. This method consist of a procedure of shaking a sample for a long period of time there by exploiting the whole volume of the soil which is in contrast to the actual plant mode of uptake. This method has also practical limitations in employing it for a routine soil analysis, as it is very expensive and time consuming. The objectives of this study were (i) to study the changes in labile, non-labile and residual P using successive P desorption by DMT-HFO followed by a subsequent fractionation method (combined method) (ii) to assess how the information gained from P desorption kinetic data relates to plant growth at green house and field trials (iii) to investigate the effect of varying shaking time on DMT-HFO extractable P and (iv) to propose a short cut approach to the combined method. The release kinetics of the plots from long term fertilizer trials at the University of Pretoria and Ermelo were studied. P desorption kinetics were described relatively well by a two-component first-order model (R2 = 0.947, 0.918, & 0.993 for NPK, MNK, & MNPK treatments respectively). The relative contributions of both the labile pool (SPA) and the less labile pool (SPB) to the total P extracted increased with increased P supply levels. Significant correlations were observed between the rate coefficients and maize grain yield for both soil types. The correlation between the cumulative P extracted and maize yield (r = 0.997**) however was highly significant for Ermelo soils. This method was also used to determine the changes in the different P pools and to relate these P fractions with maize yield. Highly significant correlations were observed between maize grain yield and the different P fractions including total P. In both soil types the contribution of both the labile and non-labile inorganic P fractions in replenishing the solution Pi was significant where as the contributions from the organic fractions were limited. The C/HCl-Pi is the fraction that decreased most in both cases as well. Investigation was carried out to evaluate the effect of varying shaking periods on the extractable DMT-HFO-Pi for UP soils of varying P levels. Four shaking options were applied. Significant difference was observed for the treatment of high P application. Shaking option 2 seemed relatively better than the others since it showed the strongest correlation. Thus for soils with high releasing kinetics and high total P content, provided that the P release from the soil is a rate limiting step, reducing the length of shaking time could shorten the duration one needs to complete the experiment with out influencing the predicting capacity of the methodology. The other objective of this thesis was also to present a short cut method alternative to the combined fractionation method. Comparison of the sum of DMT-HFO-Pi, NaHCO3-Pi, NaOH-Pi, D/HCl-Pi and C/HCl-Pi extracted by a conventional step-by-step method with the sum of DMT-HFO-Pi and a single C/HCl-Pi extraction as a short cut approach for all extraction periods resulted in strong and significant correlations. The C/HCl-Pi fraction extracted by both methods was correlated with maize grain yield and it was found to be highly significant. This study revealed that this short cut approach could be a simplified and economically viable option to study the P dynamics of soils especially for soils where the P pool acting as a source in replenishing the labile portion of P is already identified. The method employed here therefore could act as an analytical tool to approximate successive cropping experiments carried out under green house or field condition. However, data from a wider range of soils is needed to evaluate the universality of this method. More work is also required in relating desorption indices of this method with yield parameters especially at field level.
Download or read book Chemical Processes in Soils written by M. A. Tabatabai and published by . This book was released on 2005 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Agrindex written by and published by . This book was released on 1993 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book World fertilizer trends and outlook to 2022 written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2019-10-30 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the world nitrogen, phosphorus and potassium fertilizer medium-term supply and demand forecasts for the period 2017-2022. FAO, in collaboration with other members of the Fertilizer Outlook Expert Group dealing with fertilizer production, consumption and trade, provides forecasts of world and regional fertilizer supply, demand and potential balance.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1990 with total page 1842 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 1086 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1973- include the following subject areas: Biological sciences, Agriculture, Chemistry, Environmental sciences, Health sciences, Engineering, Mathematics and statistics, Earth sciences, Physics, Education, Psychology, Sociology, Anthropology, History, Law & political science, Business & economics, Geography & regional planning, Language & literature, Fine arts, Library & information science, Mass communications, Music, Philosophy and Religion.
Download or read book Rice written by Achim Dobermann and published by Int. Rice Res. Inst.. This book was released on 2000 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rice ecosystems; Nutrient management; Mineral deficiencies; Mineral toxicities; Tools and information.
Download or read book Handbook of Plant Nutrition written by Allen V. Barker and published by CRC Press. This book was released on 2016-04-19 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt: The burgeoning demand on the world food supply, coupled with concern over the use of chemical fertilizers, has led to an accelerated interest in the practice of precision agriculture. This practice involves the careful control and monitoring of plant nutrition to maximize the rate of growth and yield of crops, as well as their nutritional value.
Download or read book Harmful Cyanobacteria written by Jef Huisman and published by Springer Science & Business Media. This book was released on 2005-06-15 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This outstanding volume provides an up-to-date overview of the advances in our knowledge of harmful cyanobacteria. An essential reference for all scientists and environmental professionals interested in cyanobacterial ecology and water management.
Download or read book Organic Matter and Rice written by and published by Int. Rice Res. Inst.. This book was released on 1984 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Legacy Phosphorus in Agriculture Role of Past Management and Perspectives for the Future written by Luke Gatiboni and published by Frontiers Media SA. This book was released on 2021-01-07 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Nutrient Acquisition written by N. Ae and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: New research reveals that plants actively acquire nutrients; the acquisition process is not a passive one in which plants simply wait for dissolved nutrients to come closer to their roots. In fact plants play a far more active role than once was understood to be possible in nutrient acquisition and in adaptation to problem soils. This book presents an excellent overview and summary of new concepts of plant nutrient acquisition mechanisms, and sets forth their practical implications in crop production. The scope is wide ranging, from biochemical, molecular, and genetic analysis of nutrient acquisition to global nutritional problems. Especially noteworthy are the sections on the cell apoplast, phosphorus-solubilizing organisms, and direct uptake of macro-organic molecules. With contributions by leading scientists worldwide, the book provides an invaluable resource for researchers in plant and environmental sciences and in agronomy and other branches of agriculture.
Download or read book Phosphorus Recovery and Recycling written by Hisao Ohtake and published by Springer. This book was released on 2018-05-25 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the engineering aspects of phosphorus (P) recovery and recycling, presenting recent research advances and applications of technologies in this important and challenging area of engineering. It highlights full-scale applications to illustrate the performance and effectiveness of the new technologies. As an essential element for all living organisms, P cannot be replaced by any other element in biochemical processes, humans ultimately rely its availability. Today, P is mostly obtained from mined rock phosphate (Pi). However, natural reserves of high-grade rock Pi are limited and dwindling on a global scale. As such, there have been increased efforts to recycle P from secondary sources, including sewage sludge, animal manure, food waste, and steelmaking slag, and so close the anthropogenic P cycle. In addition to various aspects of phosphorus covered by other literature, including chemistry, biochemistry, ecology, soil-plant systems and sustainable management, this book is a valuable and comprehensive source of information on the rapidly evolving field of P recovery and recycling engineering for students, researchers, and professionals responsible for sustainable use of phosphorus.
Download or read book Agronomy and Economy of Black Pepper and Cardamom written by K.P. Prabhakaran Nair and published by Elsevier. This book was released on 2011-07-12 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Known as the "King" of spices, black pepper (Piper nigrum L.) and the "Queen" of spices, cardamom (Elettaria cardamomum M.), both perennial crops of the tropics, are the most important and most widely sought after spice crops of the world. They both have many uses, for example, both are used as flavourings and as a medicine. This book provides a comprehensive review of these two very important spice crops, covering origin, history, geographical distribution, production, economy and their uses. Discusses the two major spices of great economic value to the developing world The author is an eminent scientist who has won numerous awards for his work in this area
Download or read book Properties and Management of Soils in the Tropics written by Pedro A. Sanchez and published by Cambridge University Press. This book was released on 2019-01-10 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-awaited second edition of classic textbook, brought completely up to date, for courses on tropical soils, and reference for scientists and professionals.
Download or read book Efficiency of Soil and Fertilizer Phosphorus Use written by John Keith Syers and published by Fao Fertilizer and Plant Nutri. This book was released on 2008 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficient use of phosphorus (P) is essential to many agricultural and environmental issues. This bulletin reviews, analyses and synthesizes information on the efficient use of soil and fertilizer P. It presents information on the plant availability of soil and fertilizer P, with an emphasis on soil plant interactions. The focus is on the changing concepts of the behaviour of both soil and fertilizer P and on the need to define and assess their recovery and, thus, P-use efficiency more appropriately.
