Site-specific agriculture has the potential to improve management of crop production inputs and efficiency of use. Improved technologies should be applied when a need is identified and implementation is feasible. Currently, technology costs and our capacity to reliably delineate or map properties affecting crop production does not always allow maximum benefit to be derived from site-specific services. This will likely improve as the costs for certain technologies decrease and there is a better understanding about variability management. Today a whole range of "new technologies" are often thrown together as the site-specific approach. These include GPS, GIS, yield monitoring, grid soil sampling, variable rate application, remote sensing, and more. One must understand each of these, and determine if, when, and where there is a fit for each. In other words, there should be a clear understanding of the benefit for each possible segment of the site-specific approach, and the relationship each has to potential improvement in the crop production system. All may not be useful. Not all areas of crop production may benefit from a site-specific approach. This must be considered as site-specific services are delivered to the farmer. Soil sampling and yield monitoring, combined with variable lime and fertilizer application, are today the most prominent components of site specific services. Our discussion of site-specific agriculture will focus on these topics (much of the following information was taken from Sawyer, 1994a).