It's easy to get excited about precision farming. But Mike Daniels, University of Arkansas environmental management specialist, offers a few words of caution.

"Farmers need to know that the GIS-GPS technology may not make them any money and takes time," says Daniels. "It is still a new tool."

GIS and GPS are, of course, Global Information Systems software and Global Positioning Systems hardware - two main components of precision farming technology.

Daniels pointed out potential precision farming pitfalls at a recent Arkansas Soybean Association seminar.

"It won't make you money if there is no variability in yield," he says. "And if yields do vary within fields, you must determine what factors are causing it and if those factors can be effectively manipulated with variable-rate technology."

For example, variable-rate fertilizer applications won't be the right solution to yield variability if soil fertility isn't what's causing it.

Still, most fields do vary in yield, so the technology usually can be beneficial if set up and used correctly.

Precision farming can involve as little an investment as a yield monitor on the combine and a map-making device. Or it could be the whole nine yards, including a soil sampler and variable-rate equipment. Of course, that's when a powerful computer system is necessary.

Daniels estimates that costs range from about $7,000 to any amount you have to spend.

Systems can be bought piecemeal. But if you choose that route, you'll need to buy components that work together and will be compatible with future additions.

"There is no standard architecture for GIS data, so make sure up front that the software you select can be used with the other precision-agriculture equipment you have," Daniels advises.

Also, the equipment must be carefully set up and calibrated to ensure accurate information. Data collected with yield monitors can be influenced by grain type, moisture and variety, requiring frequent recalibration.

"This is not a time-saving practice or a quick fix. It is a way to collect more precise data, but the data still has to be analyzed and understood to make good management decisions." GIS information is not necessarily easy to interpret.

"The data produces maps - all kinds of maps - but determining what they mean takes some education and time to learn."

Keeping good records for easy retrieval is also essential to get the most from a GIS-GPS investment. That includes keeping detailed records of factors that can influence yield, such as drainage, plant populations, hybrids or varieties planted, weed and insect problems, etc., says Daniels.