I found a wonderful UGA site that tells how to convert the results of a soil test to the amount of organic fertilizer to apply. It even has tables for common recommendations like 10-10-10 or 5-10-15. The equations are for 1000 square feet or for a 100 foot linear row. It would be easy to calculate smaller and larger areas once you have the 1000 square foot calculations.

An interesting tidbit for those who use compost to fertilize - it takes 33 pounds of compost to equal enough 10-10-10 to cover 1000 square feet. Yeeesh!

Here is a link that might be useful: Fertilizer Conversion