Water Repellent Soils

It has become clear that soil water repellency is much more wide-spread than formerly thought. Water repellency has been reported in most continents of the world for varying land uses and climatic conditions. Soil water repellency often leads to severe runoff and erosion, rapid leaching of surface-applied agrichemicals, and losses of water and nutrient availability for crops. At present, no optimum management strategies exist for water repellent soils, focusing on minimizing environmental risks while maintaining crop production. The book starts with a historical overview of water repellency research, followed by seven thematic sections covering 26 research chapters. The first section discusses the origin, the second the assessment, and the third the occurrence and hydrological implications of soil water repellency. The fourth section is devoted to the effect of fire on water repellency, section five deals with the physics and modeling of flow and transport in water repellent soils, section six presents amelioration techniques and farming strategies to combat soil water repellency, and section seven concludes the book with an extensive bibliography on soil water repellency.

This state-of-the-art book clearly explains the basic principles of soil hydrology and the current knowledge in this field. It particularly highlights the estimation and application of measurements and evaluation of soil-hydrophysical characteristics using simulation models, with a focus on elucidating the basic hydrophysical characteristics of soil, such as soil water potential and hydraulic conductivity, as well as the methods of measurement. It also addresses topics such as stony soil, water repellent soils, and water movement modeling in those media. The book presents soil hydrology in a simple way, while quantitatively expressing the soil water state and movement. It clearly and precisely describes basic terms of soil hydrology with a minimum of mathematics. It also includes the latest research findings in the field as well as the basics of the mathematical modeling of water movement in the soil-plant-atmosphere system (SPAS), using original research results to illustrate these issues. This book is of interest to all scientists and professionals in soil hydrology, including beginners, as well as those interested and working in hydrology in general and soil hydrology in particular. In addition, it can also be used by specialists and students in related fields like agronomy, forestry, meteorology, hydrology, environmental engineering, environmental protection, and geography.

This Encyclopedia of Agrophysics will provide up-to-date information on the physical properties and processes affecting the quality of the environment and plant production. It will be a "first-up" volume which will nicely complement the recently published Encyclopedia of Soil Science, (November 2007) which was published in the same series. In a single authoritative volume a collection of about 250 informative articles and ca 400 glossary terms covering all aspects of agrophysics will be presented. The authors will be renowned specialists in various aspects in agrophysics from a wide variety of countries. Agrophysics is important both for research and practical use not only in agriculture, but also in areas like environmental science, land reclamation, food processing etc. Agrophysics is a relatively new interdisciplinary field closely related to Agrochemistry, Agrobiology, Agroclimatology and Agroecology. Nowadays it has been fully accepted as an agricultural and environmental discipline. As such this Encyclopedia volume will be an indispensable working tool for scientists and practitioners from different disciplines, like agriculture, soil science, geosciences, environmental science, geography, and engineering.

Excerpt from Infiltration and Water Repellency in Granitic Soils The mechanisms involved in the formation of water-repellent soils are not well understood, partly because the hydrophobic compounds have not been identified. These compounds are formed and released from plants and plant residues by decomposition and pyrolysis. They may be formed in the soil by fungi and other microflora (bond and Harris 1964) or they may move into the soil after formation elsewhere. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The key to sustaining the soil resource base is to maintain, or enhance, soil quality. Soil quality cannot be seen or measured directly from the soil alone but is inferred from soil characteristics and soil behavior under defined conditions. In essence, the quality of soils is analogous to the health of humans, and just as there is no single characteristic that can be measured to quantify a person's health, there is no single measurement that can quantify soil quality. However, there are certain characteristics, particularly when considered together, that are good indicators. Soil quality, just as human health, can be maintained or enhanced by good management practices; and seriously degraded-sometimes irrevers ibly-with poor practices. Soil quality is also important because it has direct and indirect effects on air quality and water quality. While the enhancement of soil quality does not always assure parallel improvements in the quality of air and, particularly, water resources, this is often the case. However, soil deg radation is invariably accompanied by degraded qualities of both air and water resources. The consensus among many scientists is that the greatest challenge is not increasing production, but preventing serious deterioration of the soil and water resource base so that the production level can be sustained.