David Keisler

David Keisler

Nitrogen is an element which has seven protons in its nucleus and therefore has been assigned the atomic number 7 as noted on the periodic chart. Nitrogen therefore has seven electrons orbiting its nucleus and it is the configuration of those electrons that establishes the chemical properties of the elements. Our atmosphere is composed of about 78% nitrogen gas, two atoms of nitrogen linked together and written as N2. The other 28% is mainly oxygen gas as O2.

Nitrogen in our atmosphere is an inert gas which may seem useless but, if converted to a reactive form such as ammonia or NH3, nitrogen is then very useful as fertilizer for plants. Plants need nitrogen for healthy growth, but only a few plants, such as beans, along with the help of microbes in their roots are capable of drawing nitrogen from the air.

For example corn can not "fix" or withdraw nitrogen from the atmosphere. However, rotating crops such as corn with beans or alfalfa, which can fix nitrogen and therefore put nitrogen back into the soil, is a useful farming practice as rotation promotes a healthy crop.

The application of natural fertilizers such as manure to crops is an ancient farming practice. The use of synthetic or manmade fertilizers is relatively new, however. A German chemist named Fritz Haber invented a process which converted atmospheric nitrogen into ammonia, or NH3. Haber won the Nobel Prize in 1918, and his method was improved by Carl Bosch, who also became a Nobel Laureate. The Haber-Bosch process is responsible for most of the synthetic fertilizer being produced today. It has been estimated that synthetic fertilizer has essentially doubled the amount of food that can grown globally. About half of today's synthetic fertilizer is used to grow wheat, rice and corn.

Therefore artificial fertilizers have aided in feeding the hungry and allow many to live healthier lives. However, it has also been estimated that 40% of chemical fertilizers are washed away into streams, rivers and eventually oceans. This form of nitrogen feeds algae and other aquatic plants. When these plants die, they are consumed my microorganisms from lower depths, and microbe respiration consumes a significant amount of oceanic oxygen. Large areas are then oxygen depleted and converted into dead zones, some of which may cover as many as 23,000 square miles of ocean.

Photosynthesis is the process in which plants use sunlight to convert atmospheric carbon dioxide plus water into oxygen and also chemical energy in the form of glucose. The process of photosynthesis may have evolved billions of years ago. Plants need nitrogen for photosynthesis – it is an essential requirement. Nitrogen is a significant component of chlorophyll.

Nitrogen is also a significant component of amino acids, the building blocks of protein. Nucleic acids such as DNA require nitrogen.

Some farming sites of wheat and barley that are over 8,000 years old have high concentrations of nitrogen consistent with having been fertilized with manure. Organic fertilizers are derived from either plants or animals. Native Americans taught the early settlers to place fish next to each stalk of corn. This, of course, was an organic fertilizer that provided nitrogen as well as other nutrients. The corn crop was so successful for the early settlers it became the centerpiece of the first Thanksgiving.

There are benefits to organic fertilizers as well as the synthetic forms, and nitrogen plays an important role in the crops produced by both. Plants provide oxygen as well as food. We need to become better stewards of the land and the oceans. Mother Nature has provided us with all that we need – let us use our resources wisely.

David Keisler is a gastroenterologist and internist in Aiken.