The soil compaction process; Methods of measuring soil compaction; Forces causing soil compaction; Compaction as it affects soil conditions; Soil conditions as they affect plant establishment, root development and yield; Effect of tillage on soil compaction; Management factors and natural forces as related to compaction; Economic assessment of soil compaction.

This book provides a global review of the mechanisms, incidence and control measures related to the problems of soil compaction in agriculture, forestry and other cropping systems. Among the disciplines which relate to this subject are soil physics, soil mechanics, vehicle mechanics, agricultural engineering, plant physiology, agronomy, pedology, climatology and economics.The volume will be of great value to soil scientists, agricultural engineers, and all those involved with irrigation, drainage and tillage. It will help to facilitate the exchange of information on current work throughout the world, as well as to promote scientific understanding and stimulate the development, evaluation and adoption of practical solutions to these widespread and urgent problems.

The purpose of this report is to review available information on soil compaction as related to soil and water conservation on forest and range lands.

Agricultural soils are subjected to many applied mechanical stresses that influence their behavior. Stresses arise from tillage machines, seeders and chemicals applicators, tractors, and equipment for harvest and transport. Applied stresses may compact or loosen the bulk soil. Micro sections of soil (aggregates or clods) may be compacted during tillage while the bulk soil is loosened. Because most granular soils are combined into structural units of varying sizes with different strengths and properties, prediction of the effect of stresses on the behavior of bulk soils is difficult. The basic strength properties of soil are determined by many fac tors: the size distribution of particles, chemical and mineralogical properties of inorganic clay fraction, the organic matter content and composition, the water content and the stress history. These factors combine and interact to produce many possible behavior patterns. Changes in structure of the soil from applied stresses and biologi cal reactions may profoundly influence storage and transmission of water, heat, and air, and the mechanical resistance to penetration by plant roots. They may also affect the traction of vehicles. Manipulation of structural properties of soils by tillage implements is a major cost under most crop production systems. Reduced energy use is also a significant conservation objective. Improved management systems are very dependent upon a better understanding of soils' response to applied stresses. The content of this book resulted from a NATO Advanced Research Workshop held in St. Paul, Minnesota, U.S.A. September 13-16, 1988.