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Nitrogen Surrounds Us  

We know that nitrogen is essential for life because it is contained in our proteins and nucleic acids. Review our Cells Are Us unit on proteins. Nitrogen makes up over 70% of the atmosphere in the form of nitrogen gas (N2), and it is contained in the soil in the form of nitrates (NO3) and ammonia (NH4). Certain bacteria can turn atmospheric nitrogen into nitrogen compounds that plants can use. 

Nitrogen Cycle. Source:

The bacterial action is an important step in the nitrogen cycle, making it possible for ecosystems to use the nitrogen in the air.

In the early 19th century, scientists carried out many experiments in order to understand how certain kinds of plants, legumes, were able to capture nitrogen from the air and make it available as "fertilizer" for the plants. In 1838, Jean Baptiste Boussingault performed some crop rotation studies with legumes over 5-years and concluded that the atmosphere was the source of the nitrogen.  Scientists later discovered in the 1880s that in order to fix or get nitrogen, plants had to contain certain bacteria in their roots. Click here for more information. 

An Ecosystem Wouldn’t be Complete Without Rot

The process of decomposition enables the carbon and nitrogen contained in dead plants and animals to get recycled back into the environment.  Any dead organic matter will eventually decompose into the environment if it is left alone. this may take months or even years.  However, if the right conditions are created, organic material can be quickly decomposed into the soil.  Farmers can take advantage of this process and naturally add nutrients and fertility to soil by making compost piles.   

A compost pile is a pile of organic matter that decomposes to add nutrients to the soil.  In order to create a successful compost pile, a farmer must add moisture, soil, extra sources of carbon and nitrogen, and continuously stir up the pile to provide it with oxygen.  If the farmer left the pile alone, the compost would take forever to break down.  Microscopic organisms contained in the soil (primarily bacteria) feed on the organic matter and provide nutrients to the soil in the process.  





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