ABSTRACT
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Many of the most important relationships between living organisms and the environment
are ultimately controlled by the amount of available incoming energy received at the
Earth’s surface from the sun. It is this energy which helps to drive soil systems. The sun’s
energy enables plants to convert inorganic chemicals into organic compounds. Living
organisms use energy in either of two forms: radiant or fixed. Radiant energy exists in the
form of electromagnetic energy, such as light, while fixed energy is the potential chemical
energy bound in organic substances. This latter energy can be and is released through the
biological process known as respiration.
