A growing human population demands increased food production. Farmers try to meet that demand by intensive farming, using fertilisers and pesticides that are impacting on the environment.
The chemical element nitrogen is important to living organisms because it is a component of all the different amino acids that are used to make proteins.
Nitrates dissolve in water and are then absorbed into plants. Animals must consume plants or other animals to obtain the amino acids needed for protein synthesis.
Humans can add nitrates to the soil artificially using chemical fertilisers. This can increase the yield of crop plants grown in the soil.