Professional Development Program






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Unit 1: Basic Ecological Concepts and Principles Related to Agricultural Systems

Applying these definitions to agriculture, a farm or ranch is actually a type of ecosystem managed with the intent to produce some harvested product (output) that is removed from the system for sale or consumption. Whether we are aware of it or not, farming is essentially the business of managing the flow of energy or the complementary relations (see Odum and Gliessman definitions on previous page) for our own benefit. Although natural ecosystems and agroecosystems can occupy similar spaces, receiving the same natural inputs from the sun and atmosphere, agroecosystems receive additional inputs (some intentional, others not) as part of production and harvest.
What are some added inputs? And what are some outputs in addition to the harvested product? Click on the arrows below to learn more about inputs and outputs in agroecosystems.


Natural inputs: carbon, oxygen, moisture from rainfall, energy and heat from the sun. Purchased (non-natural, manufactured) inputs: chemicals, pesticides, fuel, seed, equipment, fertilizers and electricity. Other inputs: human labor, animal labor.


Desirable outputs are food, feed, fuel and fiber. Undesirable outputs may be soil from erosion, chemical contaminants, or greenhouse gases. What are the agricultural outputs in the agroecosystems you work in?

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