Phytonutrients

Fertilizers contain nutrients (foods) that are essential for plant growth. Some fertilizers are made from organic materials, such as animal manure or sewage, and others are made from minerals or factory-produced compounds. Man has used fertilizers for thousands of years, even at times when he was unaware of their usefulness to plants, and long before man understood the importance of plant nutrition. He noticed that animal dung, wood ashes, and some other minerals helped plants grow vigorously. During the nineteenth and early twentieth centuries, researchers discovered that certain chemical elements are necessary for plant nutrition.