Volume 51 is a compilation of cutting-edge reviews written by leading crop and soil scientists. Several chapters emphasize ecology and the environment: conservation tillage with emphasis on ecological approaches to soil management, especially its effects on the environment, soil physical and chemical properties, and surface mulch, nutrient, and pest management; a complete and contemporary review on integrated pest management, ecological and environmental considerations, and future directions; a comprehensive review of cadmium accumulation in plants and its effects on human health. Other topics which are of interest to agronomists around the world include a comprehensive review on gypsum and acid soils; and transposable elements in maize and their role in creating plant genetic variability.