Precision farming consists of 1) gathering information to identify areas of a field where the crop needs different amounts of an input, 2) determining amounts of the input needed by the crop in those areas, and 3) applying the needed amounts of the input in each area. This study shows that gathering site-specific information about a field can help a farmer make more economically sound decisions and that variable rate nitrogen application potentially can increase yield, decrease nitrogen use, and increase net return. These benefits are shown for a cotton farmer who wants to maximize profits from a cotton field where yield response to nitrogen is poor on 50% of the field and good on the other 50% of the field.