Within the field of soil science, soil chemistry encompasses the different chemical processes that take place, including mineral weathering, humification of organic plant residues, and ionic reactions involving natural and foreign metal ions that play significant roles in soil. Chemical reactions occur both in the soil solution and at the soil part

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S. Henin Versailles, France It was a pleasure for me to take part in the NATO Advanced Study Workshop for studies of 'Soil Colloids and their Associations in Soil Aggregates'. The meeting provided me with a welcome opportunity to renew acquaintances with respected colleagues in the various fields of Soil Science, to listen to their presentations, and be involved in discussions which were at the frontiers of the science which deals with the structures and the associations of the soil colloidal constituents. In my view the rapid advances in Soil Science, and the great benefits to agriculture from these, have their origins in the emerging understanding of the structures and the associations of the different soil colloids. It is clear that much research is still needed before the molecular details of the most important of the structures and of the interactions are fully understood. The associations between the soil colloids, and the manner in which they bind to or hold the other constituents of soils in aggregates is fundamental to soil fertility. and the Modem intensive agriculture leads to the degradation of soil structure subsequent loss through erosion of a resource that is vital for the production of food. This degradation is considered to result primarily from the biological oxidation of the indigenous soil organic matter, and from the failure to return to the soil sufficient organic residues to compensate for such losses.

About 20 years ago the emphasis in soil chemistry research switched from studies of problems related to scarcities of plant nutrients to those arising from soil pollutants. The new problems have come about because of the excessive uses of fertilizers, the inputs from farm and industrial wastes, the widespread applications of anthropogenie xenobiotic chemicals, and the deterioration of soil structure resulting from certain modern agriculture practises. The International Society of Soil Science (ISSS) recognized these problems and challenges. A provisional Working Group was set up in 1978 to focus attention on soil colloids with a view to understanding better the interactions wh ich take place at their surfaces. It was recognized that these interactions are fundamental to problems of soil fertility, as weIl as to those of soil pollution. After the group had received the official support of ISSS at its 12th International Congress in New Delhi in 1982 it set as its priority the assembling and evaluation of information, relevant to the soil and environmental sciences, concerning the composition and structure of soil colloids. Prior to that aseries of Position Papers were published in the Bulletin of the International Society of Soil Science (Vol. 61, 1981) outlining the state of knowledge about the composition and properties of soil colloids.

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Agricultural ecology, or agroecology, deals in general with the structure and function of agroecosystems at different levels of resolution. In this text/reference, the authors describe in terms of agroecology the tropical environments of sub-Saharan Africa, Southeast Asia, and Latin and Central America, focusing on production and management systems unique to each region.

Learn the secrets of soil chemistry and its role in agriculture and the environment. Examine the fundamental laws of soil chemistry, how they affect dissolution, cation and anion exchange, and other reactions. Explore how water can form water-bridges and hydrogen bonding, the most common forces in adsorption, chelation, and more. Discover how electrical charges develop in soils creating electrochemical potentials forcing ions to move into the plant body through barriers such as root membranes, nourishing crops and plants. You can do all this and more with Principles of Soil Chemistry, Fourth Edition. Since the first edition published in 1982, this resource has made a name for itself as a textbook for upper level undergraduates and as a handy reference for professionals and scientists. This fourth edition reexamines the entire reach of soil chemistry while maintaining the clear, concise style that made previous editions so user-friendly. By completely revising, updating, and incorporating a decade’s worth of new information, author Kim Tan has made this edition an entirely new and better book. See what's new in the Fourth Edition Reexamines atoms as the smallest particle that will enter into chemical reactions by probing new advances testifying the presence of subatomic particles and concepts such as string theory Underscores oxygen as the key element in soil air and atmosphere for life on earth Reevaluates the idea of transformation of orthoclase into albite by simple cation exchange reactions as misleading and bending scientific concepts of ion exchange over the limit of truth Examines the role of fertilizers, sulfur, pyrite, acid rain, and nitrogen fixation in soil acidity, underscoring the controversial effect of nitrification on increasing soil acidity over time Addresses the old and new approaches to humic acids by comparing the traditional operational concept against the currently proposed supramolecular and pseudomicellar concept Proposes soil organics, such as nucleic acids of DNA and others, to also adsorb cation ions held as diffusive ion clouds around the polymers Tan explains, in easy and simple language, the chemical make-up of the four soil constituents, their chemical reactions and interactions in soils as governed by basic chemical laws, and their importance in agriculture, industry, and the environment. He differentiates soil chemistry from geochemistry and physical chemistry. Containing more than 200 equations, 123 figures, and 38 tables, this popular text and resource supplies a comprehensive treatment of soil chemistry that builds a foundation for work in environmental pollution, organic and inorganic soil contamination, and potential ecological health and environmental health risks.

The Role of Colloidal Systems in Environmental Protection describes the importance of colloids in many applications that contribute to environmental protection, including drinking water and wastewater treatment, heavy metal remediation, treatment of radioactive materials, corrosion, and energy conversion. Knowledge of the physical and chemical composition of colloids is important to understand and accurately model the relevant processes. The book familiarizes the reader with the technological features of the application of colloids in environmental protection, and provides chemical engineers, researchers, and scientists in academic and corporate communities with the latest developments in this field. Each chapter covers the whole spectrum of the relevant science, from the fundamentals to applications. - Provides the applied technological features of colloids in environmental protection - Gives insight into the use of bio-solid colloids as contaminant carriers - Covers the natural occurrence of biosurfactants in the environment and their applications - Provides information on the use of nanoparticles for environmental applications - Chapters written by recognized and respected experts in the field from all over the world