Why do plants benefit from nitrogen fertilization?

Nitrogen fertilizer contains nitrates. Nitrates are essential for making protein.

The fertilizer may also contain compounds with phosphorus, and potassium. Phosphorus is broken down and combined with other chemicals before the plant is able to absorb it. Phosphorus then combines with other chemicals to form ions. Potassium is an essential element for plant growth. It is commonly applied to gardens, lawns and orchards as part of a balanced fertilizer. Potassium, often called potash, helps plants use water and resist drought. It promotes healthy green lawn grass. Potassium is important to food crops and enhances the size of fruits and vegetables.

Nitrogen makes up 78 percent of the earth's atmosphere but this is unavailable to plants and animals until it is turned into a nitrate. Bacteria in the soil turn nitrogen into nitrates. Without it, green plants are weak and smaller than they should be. Too much nitrogen, on the other hand, makes plants unable to withstand frosts or heavy winds. While many chemical fertilizers contain nitrates, there are also natural sources of the element that do not put the environment at as much risk of pollution.