When it comes to determining precision ag adoption, two surveys shed light on what's popular with fertilizer and pesticide dealers and farmers.
Purdue University and CropLife magazine surveyed fertilizer and pesticide dealers nationwide. Ohio State University (OSU) surveyed farmers within the state with gross sales of $50,000 or more.
The Purdue survey included 343 useable responses. Of the dealers that offer custom application, 76% said they were applying at least some fertilizer or chemicals using a GPS-based lightbar guidance system with manual steering. Among that same group of custom applicators, 20% said they used a GPS guidance system with automated steering, which is an increase from 6% in 2005.
Among the Ohio farmers, 31.6% were using lightbar guidance or auto-steering, up from only 5.2% in 2003. Lightbar or auto-steering systems were the second-most popular precision ag technologies, trailing yield monitors by a mere 0.1%.
"There is growing interest in automated [guidance] systems because dealers and farmers see the benefits very quickly, in terms of fewer skips and overlaps," says Jess Lowenberg-DeBoer, a Purdue ag economist. "There also are benefits from reduced stress and fatigue, which may translate into the ability to work longer hours."
Variable-rate technology (VRT) application of fertilizer, chemicals and seed is a logical use for GPS technology. In the Ohio survey, a majority of respondents thought VRT technology would pay on their farms. But its adoption rate is only two-thirds that of auto-guidance.
Among Ohio farmers, 22.2% were spreading lime with VRT, 19.6% phosphorus (P) and 19.5% potassium (K). In 2003, the adoption rates stood at 14% for lime, 14.1% for P and 13.4% for K.
Among dealers, the Purdue study showed 51% were offering controller-driven VRT application of fertilizer, lime or chemicals. VRT application was two to three times more common in the Midwest than in other regions. Fertilizer and lime were applied with VRT more than twice as frequently as chemicals.
Unlike with guidance systems, most farmers can't easily see a payoff with VRT, Lowenberg-DeBoer says. "For variable-rate application to pay, the need has to be dramatically different in some areas of the field," he says. "You need a soil sampling strategy that picks up those differences. To do that, our studies show you need to test on areas of less than an acre, but 2½-acre grids are still the most commonly used. To make VRT generally profitable, corn, soybean and fertilizer prices all need to be much higher than they are now."
In the Ohio survey, reports of VRT application of nitrogen (10.7%), seed (8.1%) and herbicides (7.1%) were lower than P, K and lime applications with VRT.
In most cases, corn and soybean growers don't have dependable ways to identify the areas within fields that need special treatment, Lowenberg-DeBoer explains. Available site-specific pesticide maps are hard to develop because insects and plant diseases quickly develop and move within fields.