Next up ROBOTS

Mar 1, 2007 12:00 PM, By Jodie Wehrspann

Robotics, he says, are highly developed forms of embodied knowledge in which a device or group of devices performs autonomous tasks under the control of a programmed computer. These tasks could include crop scouting, weeding, irrigation, microspraying or harvesting.

He says that, by reducing labor, robotics may facilitate certain crop management practices that farmers in the U.S. have shied away from simply because of high labor costs. “Organic production is a classic example,” he says. “One of the great barriers toward organic production in the United States is that it requires more labor. With robotics, we may be able to deal with that. Another example may be intensive soil sampling. It's a very repetitive task. Sounds like something a robot could do.”

With robots doing much of the labor, VRT could become more profitable. “Present adoption of VRT depends on making precision agriculture embodied-knowledge technology that the user can simply buy as an input,” Lowenberg-DeBoer says. “I think GPS vehicle guidance will stimulate crop management creativity and improvise the next steps.”

Robotic weed control

THE ILLINOIS Council on Food and Agricultural Research has awarded the University of Illinois $300,000 to develop a special robot for weed control. Agricultural engineers at the U of I already have developed several ag robots that can guide themselves down corn rows using lasers or sensors to gauge the distance to corn plants (see “Robot farmers — cheap,” July/August 2004). U of I ag engineer Tony Grift says the new robot in development will be equipped to detect weeds and apply herbicides while navigating itself up and down the rows.

“The plan is to develop a robot that is smart enough to distinguish weeds that are glyphosate [Roundup] resistant from the nonresistant ones and then use mechanical weed control for the resistant weeds and use chemicals in minute amounts [microspray method] for the rest,” Grift says. “The main weed is waterhemp, which has been shown to be resistant in Illinois through three mechanisms, and more will follow.”

The proposal to develop the “high-efficiency, flexible, intelligent farming tools,” calls for two ag engineers, a geneticist, a systems integrator and a weed scientist. Estimated date of completion is the summer of 2009.

“This robot would be in the $5,000 price range,” Grift says. “We will contact potential manufacturers to produce this type of robot. And hopefully there will be a market, especially once more weeds become resistant in light of the cost of developing a new Roundup, which is astronomical.”

Economics of VRT

VARIABLE-RATE TECHNOLOGY (VRT) using GPS, first developed in the 1990s, allows you to vary the rates of seed, pesticide and fertilizer according to the needs of each area of a field. Those needs are determined by analyzing geo-referenced data that have been collected on your fields. By tailoring the rates, as opposed to using one uniform rate, across a field, you can apply inputs more efficiently and theoretically cut input costs and increase yields.

However, according to a review of more than 200 articles on the topic, conducted by Purdue University, VRT does not always result in an economic benefit. “Most studies to date have shown only modest returns to site-specific variable-rate applications of crop nutrients,” says Jess Lowenberg-DeBoer, agricultural economist at Purdue. He says the reason is because the gains are usually offset by the labor, sampling and equipment costs associated with site-specific management.

But what about the recent rise in fuel and fertilizer prices? To find out whether higher input prices balance out the associated costs of VRT, Lowenberg-DeBoer and colleague Bruce Erickson used earlier studies on VRT profitability and plugged in 2006 prices.

One study in particular, conducted in 1999 in Indiana, measured the net profit of applying phosphorus (P) and potassium (K) at one uniform rate and at varying rates based on 2.5-acre grids and on soil type. “In the 1999 study, varying P and K rates by soil type resulted in a net benefit of $4 to $5/acre over a single uniform rate application,” Lowenberg-DeBoer says. “Varying the rate by 2.5-acre grids showed the least benefit.

“When we plugged in 2006 prices, all three methods were less profitable, which was not surprising because costs today are higher,” he says. “But the ranking was still the same. In other words, varying rates by soil type was slightly more profitable than uniform rate technology, and the three-acre grid was still the least profitable.

“The higher energy and fertilizer prices do make variable application slightly more attractive than in the past,” he continues. “But prices are not high enough…to tip the scale conclusively to the variable-rate technology side. Whether [higher prices] will dramatically change the situation for VRT is still unknown. The associated costs of doing it will have to come down.”