Difference between Substance Farming and Subsistence Farming
Subsistence farming is a farm that barely makes a living – usually by raising a few of everything like chickens, a garden, etc. and trying to get along.
Substance farm is raising a particular crop which is turned into a substance. One you may think of is hemp which is turned into cloth, rope, etc. Flax is raised for the seed which can be eaten but it can also produce linseed oil and the straw processed for linen.
Substance farming will become more common in the future as crops are developed which produce specific chemicals or drugs (for medical purposes).
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