There is a growing need for research that estimates the potential value to farmers of acquiring and using improved information about spatial variability within their fields. This paper considers the potential value of switching from single rate technologies (SRT) to variable rate technologies (VRT) for applying nitrogen fertilizer in 12 Iowa counties. Changes in yields, nitrogen use, and profits are estimated for individual field and entire counties. The economic and environmental impacts of moving from SRT to VRT depend heavily on the amount of inherent yield variability in field.