Precision farming offers future savings.

Precision farming, also known as prescription or site-specific farming, will be the most economical method in the 21st century, Purdue University experts predict. Right now, though, the technology isn't profitable, indicates James Lowenberg-DeBoer, associate professor of agricultural economics. "You'd have to work very hard to make money with today's precision technology. However, [it] will become economically attractive as the cost comes down."

The wait may not be a long one. "It is mind-boggling how fast the technology changes. Within two to three years, we should be at something that is close to being economical."

Lowenberg-DeBoer says this time line may be shortened even more because he expects either the 1995 farm bill or water-quality legislation to offer financial or regulatory incentives for farmers to use precision farming because of its environmental benefits.

Precision farming means that, instead of applying fertilizer or pesticides to an entire field at a single rate of application, farmers test the soil and crop yields for sections ranging from one to 15 acres and apply just the amount of chemicals that part of the field needs.

Agricultural experts expect the size of the areas receiving individual treatment to drop to as small as a few square feet several years from now once the technology embraces computerized field mapping, global positioning...