This publication is a revised and updated version of World Soil Resources Reports No. 84 and 103 and presents the international soil classification system. Every soil in the world can be allocated to one of the 32 Reference Soil Groups as defined in this document, and can further be characterized by a set of qualifiers. The resulting soil name provides information on soil genesis, soil ecological function and soil properties relevant for land use and management. The same system, refined slightly, may be used to name the units of soil map legends, thereby providing comprehensive spatial information. By accommodating national soil classification systems, the World Reference Base facilitates the worldwide correlation of soil information.

change is simply described by the rate of income and rate of loss. Our home's energy budget, our firm's inventory, our nation's debt, and humanity's numbers all have accounts that change at rates that are equal to the inputs minus the outputs. Jenny's "system view" of the soil was carried into the fertile fields of Midwestern American prairies from the laboratories of Switzerland in the late 1920s. Jenny's rate equations provided the other paradigm or world view that, I recall, brought us to the threshold of systems ecology as it later evolved in the second half of the twentieth century. As if world renown in the specialties of pedology and soil chemistry were not enough for one lifetime, excerpts below remind us that Hans Jenny has also been a perceptive outdoor field ecologist since his early Alpine expeditions with Braun Blanquet in the mid 1920s. Jenny's ecosystem studies in the pygmy forest, a further classic example of a soil-plant system "run down" over hundreds of thousands of years since its origin, continue to occupy some of the vigorous retirement time near his farm in Mendocino County. But each specific, quantitative case study, and each research area conserved (with additional hard work) for further study by future generations, fits into Jenny's coherent world view. It is that view, and its legacies of discovery and of tangible landscape preserves, which we are privileged to share with their originator in this volume.

An understanding of the characteristics and the ecology of soils, particularly those of forest ecosystems in the humid tropics, is central to the development of sustainable forest management systems. The present book examines the contribution that forest soil science and forest ecology can make to sustainable land use in the humid tropics. Four main issues are addressed: characteristics and classification of forest soils, chemical and hydrological changes after forest utilization, soil fertility management in forest plantations and agroforestry systems as well as ecosystem studies from the dipterocarp forest region of Southeast Asia. Additionally, case studies include work from Guyana, Costa Rica, the Philippines, Malaysia, Australia and Nigeria.

The Encyclopedia of Soil Science provides a comprehensive, alphabetical treatment of basic soil science in a single volume. It constitutes a wide ranging and authorative collection of some 160 academic articles covering the salient aspects of soil physics, chemistry, biology, fertility, technology, genesis, morphology, classification and geomorphology. With increased usage of soil for world food production, building materials, and waste repositories, demand has grown for a better global understanding of soil and its processes. longer articles by leading authorities from around the world are supplemented by some 430 definitions of common terms in soil sciences.

Soil-The Basis of All Terrestrial LifeAncient civilizations and cultures-Mayan, Aztec, Mesopotamian, Indus, and Yangtze-were built on good soils, surviving only as long as soils had the capacity to support them. In the twenty-first century, productive soil is still the engine of economic development and essential to human well-being. The quality of