Depends on the type of soil. This site gives some general estimates:

Soil capacity is measured in pounds per square foot (psf). The load-bearing capacity of soils range from 4,000 psf for sedimentary rock to as little as 1,500 psf for clay and silt. Soils that are a predominantly sand or gravel typically fall in the middle, from 2,000-3,000 psf. In very few instances are actual soil tests done. Most inspectors will know the approximate soil-carrying capacity in the areas they cover.