Book excerpt: The chemistry of acidity. Physiological effects of hydrogen, aluminum, and managanese toxicities in acid soil. Physiological aspects of calcium, magnesium, and molybdenum deficiencies in plants. Liming materials and practices. Crop response to lime in the southern united states. Crop response to lime in the midwestern united states. Crop response to lime in the northeastern united states. Crop response to lime in the wested states. Crop response to lime on soils in the tropics. Glossary-common and scientific names of crops referred to in this monograph.