Soil acidity is a major limitation to crop production in many parts of the world. Plant growth inhibition results from a combination of factors, including aluminum, manganese, and hydrogen ion toxicities and deficiencies of essential elements, particularly calcium, magnesium, phosphorus, and molybdenum. Agricultural management practices and acid precipitation have increased acid inputs into the ecosystem and heightened concern about soil acidity problems. While application of lime has proved to be effective in ameliorating surface soil acidity in many areas, significant soil acidity problems still exist. Scientists from Alberta, Canada, recognized the need to provide a forum for researchers from different disciplines to exchange information and ideas on solving problems of plant growth in acid soils. As a result of their efforts, the First International Symposium on Plant-Soil Interactions at Low pH was held at Grande Prairie, Alberta, Canada, in July 1987. In many acid soil areas, liming materials are not readily available, the cost may be prohibitive, or subsoil acidity cannot be corrected by surface application of lime. New management approaches involving both the plant and the soil are needed in these situations. Progress has been made in the selection and breeding of acid-tolerant plants. However, continued progress will be limited by our lack of understanding of the physiological and biochemical basis of differential acidity tolerance among plants.

The understanding of plant-soil interactions in acid soils is important for improved food production in many parts of the world. The context of the book touches on basic and applied aspects of the physics, chemistry and biology of acid soils and their effect on growth of plants. It contains a large section on management of acid soils for plant (food) production and on socioeconomic aspects of management of acid soils. This is important because a large portion of the world's acid soils occurs in less developed countries. Plant-Soil Interactions at Low pH: Principles and Management contains a substantial number of papers, including nine invited reviews, presented at the Third International Symposium of Plant-Soil Interactions at Low pH. The major themes include chemistry and physics of acid soils, microbial and faunal activity in acid soils, mechanisms of acid tolerance of plants, selection and breeding of acid-tolerant plants, diagnosis and correction of acid soil infertility, socioeconomic aspects of acid soil management and management systems for agriculture, horticulture and forestry on acid soils.