In inorganic chemistry, a nitrate is a salt of nitric acid with an ion composed of one nitrogen and three oxygen atoms (NO3-). In organic chemistry the esters of nitric acid and various alcohols are called nitrates.
The highly water-soluble salt is the preferred nitrogen source of fertilizers. Most of the produced ammonium nitrate ends therefore in the production of fertilizers. However, the runoff of excess ammonium nitrate is a leading source of environmental waste.
Nitrates in soil are strings of nitrogen. Plans the the N2 out of the air and on knobs on the roots the N2 undergoes a process called nitrogen fixation where the N2 becomes N3 which is a form of nitrogen that the plant can use. A plant would rather take it out of the soil than make it because it requires energy. When a plant dies the nitrates are left in the soil for other plants to use. Intensive farming uses up these nitrates which causes the need for farmers to use fertilizer on their crops.