Fertilizer is a substance added to soil to help plants grow. Fertilizer is divided into two groups: natural and synthetic. Fertilizer provides one or more of the chemical elements essential for plant nutrition.
Synthetic fertilizers come in either liquid or solid. They are usually classified into 10 groups: nitrogen fertilizers (it can make the soil acid), ammonia (a kind of fertilizer that contains 82% nitrogen), ammonium nitrate (is made by oxidizing ammonia), ammonium sulfate and ammonium chloride (mostly made from synthetic ammonia), urea (a fertilizer that is 45% to 46% nitrogen and made by combining ammonia with carbon dioxide), others (fertilizers that are only important in few places for special crops), phosphate fertilizers (made from deposits of rock phosphates), superphosphates (made by reacting rock phosphate with sulfuric acid), basic slag (or Thomas slag, a by-product of steelmaking) , and potassium fertilizers (fertilizers that are water soluble). Synthetic fertilizers are also called chemical fertilizers. They have three groups of elements involved in making them. The primary elements include nitrogen, phosphorus, and potassium. These elements are required in the biggest amount. The secondary elements are sulfur, calcium, and magnesium. These elements are required in smaller amounts. The other elements are boron, cobalt, copper, iron, manganese, molybdenum, and zinc. These elements are only required in trace amounts.