Fertilizer use is a staple of modern agriculture, and understanding the function it serves helps farmers grow their crops. By using fertilizers, farmers can reach the optimum output that their land can produce and feed more mouths at lower cost.
Like animals, plants require nutrients to live. A plant that regularly gets needed nutrients will thrive and tend to be bigger, healthier and more resilient to disease. A nutrient-deprived plant will be smaller and more susceptible to the ravages of disease and other ailments. Most of these nutrients are taken from the soil. The most important nutrients are nitrogen, phosphorus, potassium, sulfur, magnesium and calcium. Others, however, need to be present in small amounts for the plant to be healthy.
Soils that naturally contains all the nutrients that plants need in the correct amounts are rare. Because plants use these nutrients, they can quickly be depleted from the soi. To offset this, replenishing fertilizers can be added to restock the nutrients.
By using fertilizers, farmers are able to grow more food on far less land, and this minimizes the environmental impact of farming and makes it less expensive and easier to feed larger populations.
Fertilizers are not without their critics. Excessive fertilization can damage plants, and many of the chemicals used in fertilizers can be hazardous if humans or animals are exposed to them in large amounts. In large amounts, fertilizers can pollute water supplies because of runoff from rain. Some proponents of organic agriculture argue for replacing industrially produced fertilizers with alternatives more analogous to naturally occurring substances.