Andres Duany breaks down the classifications of incorporating Agriculture into the Rural-to-Urban Transect in a Pecha Kucha format in this video from CNU 19 in Madison, WI.  Video provided by Steve Mouzon of the New Urban Guild.
Agricultural RetentionAgricultural Retention is the process and use of policy to keep the agriculture where it currently exists.
Urban Agriculture: Urban Agriculture incorporates agriculture into the existing cities in two scenarios. 1. If the city loses population, similar to what has occurred in Detroit, Michigan.  2. Through retrofitting suburbia in abandoned shopping centers, deserted or never occupied subdivisions, etc.
Agricultural Urbanism: Agricultural Urbanism locates the farm so that it is adjacent to the community.  The community contracts out to a second party to provide the food. With Agricultural Urbanism, the society does not have to grow the food, but they do purchase and consume it.
Agrarian Urbanism: Agrarian Urbanism occurs when the society grows the food for consumption within the society.