The mineral nutrients of plants play key roles in plant growth and development, forming the underpinnings of the past, present, and future of agriculture. Plants with insufficient nutrients exhibit symptoms of sickness that can be confused with infectious plant diseases. The nutrients needed by plants are taken from the soil by the roots, and in many plants, the roots also form associations with other organisms that help them more efficiently colonize the soil or provide nutrients to the plant. All facets of plant nutrition, from the effect of nutrients on the plant to the role of plants in the global cycling of nutrients, impact the ways in which humans use and depend on plants for most aspects of our existence. Plant Nutrition, Second Edition addresses the basic chemistry, biology, physiology, and ecology of plant nutrition and shows how these topics relate to humans on a personal, social, and global scale.