Sustentabilidade

“This miniaturization of agriculture is not new. Small-scale sustainable agriculture has supported such widely dispersed civilizations as the Chinese 4,000 years ago, and the Mayans, South Americans, and Greeks 2,000 years ago.
Ecology Action has dedicated almost a quarter-century to rediscovering the scientific principles that underlie these traditional systems. The people in Biosphere II in Arizona have been using techniques based on those outlined by Ecology Action: they raised 80 percent of their food for two years within a “closed system.” Their experience demonstrates that a complete year’s diet for one person can be raised on the equivalent of 3,403 square feet!”

“This is an improvement over traditional Chinese practices, which required 5,000 to 7,200 square feet. In contrast, it takes commercial agriculture 22,000 to 42,000 square feet to grow all the food for one person for one year, while bringing in large inputs from other areas. At the same time, commercial agricultural practices are causing the loss of approximately six pounds of soil for each pound of food produced.
Biointensive mini-farming techniques make it possible to grow food using 99 percent less energy in all forms - human and mechanical, 66 percent to 88 percent less water, and 50 percent to 100 percent less fertilizer, compared to commercial agriculture. They also produce two to six times more food and build the soil.”

This is, 32 meters x 32 meters for a property to cleverly produce all our necessary food (1 person for a year!) or around 1000m2 (a quarter of an acre, a tenth of hectare).
In chinese practices 42 x42 meters is necessary for producing food for feeding a person over one year (around 1800m2 or half an acre). Conventional agriculture needs around one hectare, 10000m2 or 100m x 100m).

The Biointensive Method

“The basics of this whole-system approach can be summarized as follows:
Most life in nature occurs at the interface of soil, water, air and sun. Biointensive soil preparation practices create growing beds with more surface area to maximize the effect of nature’s life processes. Double-dug beds, with soil loosened to a depth of 24 inches, aerate the soil, facilitate root growth, and improve water retention. The health and vigor of the soil are maintained through the use of compost. Close seeding spacing is used to protect the soil microorganisms, reduce water loss, and maximize yields. Companion planting facilitates the optimal use of nutrients, light and water, encourages beneficial insects and creates a vibrant mini-ecosystem within the garden. The use of open-pollinated seeds helps to preserve genetic diversity and enables gardeners to develop their own acclimatized cultivars.

A focus on the production of calories for the gardener and carbon for the soil ensures that both the gardener and the soil will be adequately fed and that the farm will be sustainable.
How can the soil’s nutrient fertility be preserved with agriculture continuously removing nutrients as one crop is harvested after another? One answer is surprising. Each person’s urine and manure contain approximately enough nutrients to produce enough food to feed that person. However, those nutrients are not enough when they are spread thinly over the one-half to one acre that it takes mechanized commercial agriculture to produce that person’s food.
Biointensive mini-farms require much less area to produce the same yield of crops, so the nutrients contained in one person’s wastes can be applied in a more concentrated way. This enables the nutrients to be fully effective, and high yields can result.

Because of this higher productivity, Biointensive practices could allow one-half to three-quarters of the world to be left in wild for the preservation of plant and animal diversity.
It has been said that Biointensive practices might make it possible to grow food for all the people in the US in just the area now used for lawns. This possibility could mean thriving agriculturally self-reliant cities with ‘green belts’ to produce all their food.”

The same results are obtained in calculations from other people, by practical experience:
http://thesietch.org/mysietch/greenspree/2007/07/17/self-sufficiency/ 0.1-0.4 acre per person or 4-people family

That would be roughly 30-40 meters per 30-4o meters square land in a property.
We could grow about 10 main cultures in ten 10×10m squares, which would give our 30×30m big square

This is a one-acre square of land for most food self-sufficiency.