These maps allow variable rate application of seeds and chemicals with equipment such as a University of Idaho-built variable variety grain drill with three bins. A 1997 test by Northwest Precision Agriculture in Blackfoot showed positive results. According to Richard Johnson, the 230-acre pivot field was divided into seven equal sections. It was fertilized by a truck that dispensed up to nine products at the same time at varying rates. The test field produced 18 percent more, and profit was up 28 percent.
Some uncertainty exists about how to use the technology correctly.
The benefit UI can provide is to keep testing to determine the best ways to use it to optimize farm profitability. Chuck Peterson, UI professor of biological and agricultural engineering, agreed. It is more difficult to demonstrate benefits on small grains than on potatoes, and it's hard to demonstrate off-site benefits. Peterson has long been concerned with precise applications of farm chemicals. Before global positioning system satellites became available to civilians, he was investigating minimum-input farming and yield mapping, research driven by a concern with water quality.