How much land should I leave fallow as part of a long-term soil fertility program in an organic production system?

Answer: The fact that you are farming your site in an organic production system means that you will be improving your soils even as you are farming them. So the longer you farm a piece of ground organically, the less necessary it becomes to worry about fallowing land. Of course, cropping with tomatoes or other vegetables will take some of the nutrients out of the soil, but not nearly as much as if you were farming conventionally. You will continually be adding compost, organic fertilizers, minerals, green manures, etc. to your soils so they will be getting replenished after every harvest. In that case, the answer to your question may be more influenced by other factors.Your location will greatly determine the answer. For example, in South Texas, one farmer is through with harvesting by mid-July at the latest and typically does not plant fall crops until Sept 1. That gives him at least six weeks to rest a piece of land and to condition it for fall planting. He may also farm a piece of land for three harvests and then let it rest for one season while planting a cover crop of rye or clover. That could be considered leaving the ground fallow for a season. This farmer also rotated crops in addition to leaving fallow. For example, he never planted tomatoes on the same ground more than two seasons in a row. He might grow spring tomatoes, then fall tomatoes, then broccoli, and then fallow for a given piece of land. And then he could start over with tomatoes again.It is always a good idea to do an annual soil test on your crop land, both to understand how to aid the soil and because it is important for your organic certification. It may also be a good idea to pick your best acres for your first plantings, and fallow the rest until you generate enough working capital to plant all of your acreage.