The University of Arizona (UA) Yuma County Cooperative Extension is employing technology to create possibly the first geo-referenced, field-level precision traceback system in the leafy greens industry.

GPS-RFID TECHNOLOGY will revolutionize how produce is tracked in the field, says Kurt Nolte, University of Arizona Cooperative Extension, Yuma County.

The project utilizes a global positioning system (GPS) and a radio frequency identification (RFID) chip/tag to construct a powerful, real-time, Web-based computer database of information during harvest.

The information is transmitted by radio to an RFID tag on the just-packed produce carton in the field.

Growers, shippers, food buyers, grocery stores, and consumers, with authorization, could access specific information in seconds on the Internet.

Recorded tags can include a plethora of information — grower names, pest control advisers, irrigators, and harvest workers involved in crop production; fertilizer rate information, harvest conditions, field names, and yield data.

The concept was developed by Kurt Nolte, director and Extension agent with the UA Cooperative Extension Service, Yuma County, Ariz. The grower-based Arizona Iceberg Lettuce Research Council funded the project.

Nolte teamed with Internet entrepreneur Joel Spencer, LittleMunk Media, Inc., Yuma, to design the prototype system for this year’s winter iceberg lettuce harvest.

The hardware is valued at about $5,000 and includes a laptop (likely to be replaced with a field computer), Trimble Pathfinder Pro GPS, Sirit RFID reader, and antenna. The operating system runs on Microsoft Windows Mobile software, while the database software is from TrackerPoint.

Nolte paid 15 cents for each RFID tag. The actual chip, the size of a pencil lead tip, is located in the center of the tag; the antenna covers the remaining area. Each harvester would require a separate GPS-RFID system.

The first system was field tested in March on an iceberg lettuce harvester at Top Flavor Farms at Bard, Calif. As cartons of lettuce were packed and sealed, proprietary information was transmitted to the tags by radio waves.

The first field test included georeferencing 2,000 cartons of lettuce in which each tag was encoded with geocoordinates, the field name, variety, and pack. Since the system does not require line-of-sight technology, the harvest crew was not even aware the system was operating.

“It worked like a charm,” Nolte says. “It took a few minutes to find a GPS signal, but once the system was booted, it worked flawlessly. I wish all field tests worked as well as this one did. I see this as a fool-proof system that could impact production for years to come. The system could revolutionize how produce is tracked in the field.”

Radio frequency waves are an integral part of the system, which does not require a harvest rig worker to scan individual cartons. The carton simply passes underneath the RFID encoder (antenna). GPS or any other pertinent crop information is wirelessly encoded on the tag.

The GPS-RFID system could allow for the traceback of every lettuce head, if necessary, to within 5 feet of where it was cut and packed in the field. In the event of a food-borne illness outbreak, Nolte says, suspect food could be tracked back to the field within 24 hours.

“This is an enormous leap forward for improved food safety traceback,” he says.

The salmonella outbreak last year took more than two months to trace to jalapeno peppers grown on a Mexican farm. Tomatoes were first suspected, costing the U.S. tomato industry millions of dollars when worried consumers reduced fresh tomato consumption.

Yield information collected at harvest can alert growers to lower-producing areas of the field and signal the need to reexamine fertilization and other efforts prior to the next planting.

“Currently, there is no yield monitor for iceberg lettuce in the world,” Nolte says. “We can track lettuce at the trailer load level in a particular field, but we can’t conduct geo-reference monitoring of lettuce for a yield map.”

The GPS-RFID prototype could be applied to every farm product packed in the field in the world, from carrots to broccoli and cauliflower, he says.

About 80 percent of the U.S. supply of winter-grown vegetables for salads is grown annually in the greater Yuma area.

Field packing into cardboard cartons is the current method for handling and transporting leafy green vegetables. The products are selected in the field for maturity and quality, and then cut, trimmed, and packed in cartons or crates, transported to a cooling facility, cooled, and kept in temporary cold storage until transported to market.

While the concept of precision trace-back is sound, the capability of developing a system for the fresh produce industry has been hampered by limitations in sensing and data processing technologies.

Low-cost RFID tags offer the rapid detection and analysis of accurate field-level yield, harvest, and tracking data, Nolte says.

The RFID tag is applied to a carton for the purpose of identification using radio waves. Most RFID tags contain at least two parts: an integrated circuit for storing and processing information, modulating, and demodulating a RF signal; and an antenna for receiving and transmitting the signal.

“To work in field conditions, the system needs to be seamless and be an asset during harvest,” says Steve Alameda, owner of Alameda Farms where the test was conducted. “With the exception of placing tags on the cartons, we didn’t even know the system was on and working.”

The incorporation of RFID into agriculture at the field level means all aspects of growing a crop could be wirelessly beamed onto the paper-thin RFID chip, providing a digital record of its management and culture in a matter of seconds, Nolte says.

“If a RFID chip with GPS longitude and latitude coordinates is placed in a field, practices used to grow the crop are impregnated in the microprocessor chip.

“Anyone involved in the food chain would simply drive by, pick up the information from the chip, and either read the current crop, download it to a laptop, or in seconds transmit the data worldwide to those who need it.”

Technology exists to actually place the RFID tag in the plastic wrapped around the lettuce head and bypass the carton itself. Spencer says current technology could even impregnate the data inside the lettuce head.

That option, if pursued, could draw lengthy, divided public and private discussion.

Consumers could also reap direct benefits from the GPS-RFID technology.

In the future, cell phones may include an RFID reader that would allow a consumer to scan a head of lettuce to determine where it was grown, the harvest date, and even download a recipe — all pre-programmed information.

The next challenge is improving the ruggedness of the system to withstand the impact of harvester movement in the field, Spencer says.

Knowing within minutes how a field harvest is progressing is very efficient, Nolte says. Such a service can be a valuable tool in the event someone on the farm or in New York needs immediate product information.

“This technology is just the tip of the iceberg,” Nolte says.

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