B.13C_Nitrogen_onlevel – 02

A small co-op of young farmers decided to grow corn organically. Corn is a crop that requires a lot of nitrogen, and growing corn causes the soil to be depleted of nitrogen. Commercial inorganic fertilizers that contain nitrogen can be added to the soil to restore nitrogen levels. However, inorganic fertilizers cannot be used for organic farming. The farmers must find another method to increase the nitrogen levels in the soil.

Why are the farmers concerned about nitrogen levels in the soil? Nitrogen is an essential element in all organisms. Plants need nitrogen to grow and reproduce. Animals obtain nitrogen by eating plants or other animals. The nitrogen in multicellular organisms is used to form important biomolecules such as amino acids, proteins, and nucleic acids.

Nitrogen is abundant in the air all around us, but plants cannot use nitrogen gas directly from the atmosphere. How does nitrogen gas in the atmosphere turn into the form that plants use? The nitrogen cycle moves nitrogen from the atmosphere to organisms and cycles nitrogen back to the atmosphere. The nitrogen cycle is a biogeochemical cycle in which atoms move between abiotic factors and biotic factors. Abiotic factors in the nitrogen cycle are the atmosphere, bodies of water, and soil. Biotic factors are bacteria, plants, and animals.

Nitrogen gas in the atmosphere is absorbed by soil or bodies of water. There are certain bacteria that can turn nitrogen gas into forms of nitrogen that can be used by producers, such as plants, algae, and phytoplankton. The bacteria can be found in soil, plant root nodules, and bodies of water.