City/Rural Relationship

  • High concentration of humans and low concentration of agriculture that are largely fed by areas outside the city that are very low in human population but are very high in agriculture.

  • Lots of humans together means that there are a lot of commonalities between them and so they can share the energy burden (public transport, shared climate in apartments, etc.)

  • Lack of space typically will mean a lack of gardens/storage so that a lot of things will have to be transported from somewhere else to be used/consumed by the population.

  • Nearly all Plants and Animals, with the exception of small animals and some trees, are completely removed from the population's living area and instead live within areas of agriculture.

Suburban/Rural Relationship

  • The population needs a significantly larger area per person area than the City/Rural Relationship and only slightly less rural area for food production.

  • Humans are still living densely enough to use some of the energy sharing techniques enjoyed by the City/Rural Relationship (public transportation, close proximity to day-to-day activities, etc.)

  • Because of the increased living space in suburbia there is often space for people to have gardens and other larger operations that can decrease the need for rural farm land and food transportation.

  • More diverse plants and animals can live in the suburbs with the human population.

Rural/Rural Relationship

  • Medium concentration of humans mixed in with a medium concentration of agriculture. More space is needed for living than in the Suburban/Rural Relationship but not as much space is needed for Agriculture.

  • Humans are no longer living densely enough to take advantage of the energy sharing benefits of the City/Rural Relationship and will often have to travel relatively long distances for their day-to-day activities.

  • Large gardens/animal farming operations can take place on an individual scale significantly reducing the need for external food, however, the need will still remain.

  • Nearly all animals and plants, with the exception of very large animals, can live within the human population.

  • What is it that you are asking here? It seems that you are trying to answer the title question in your question text. It's fine if you want to answer your own question, but please do so in an answer, not in the question itself. – THelper Aug 8 '14 at 6:50
  • Some detail about what you mean by "sustainable" would help, as the exact criteria will determine the answer (as is so often the case). I've been mulling this one for a day or so and still don't have an angle that would let me come up with an answer. The brutal one, of course, is that current evidence suggests that agriculture per se is not shown to be sustainable. Viz, any form old enough to be able to be seen as sustainable has been shown not to be. But again, define "sustainable"... does it mean "can operate unchanged for 500 years" or just "for a human generation"? – Móż Aug 8 '14 at 11:42