BASF Subsidiary Develops Better Crops Through RFID

Prior to deploying an RFID-based solution, the company had considered using a system involving bar codes, but quickly decided against it after initial experiments proved unsatisfactory. "It became clear that if you wanted it fully automated, you couldn't use bar codes," Leyns says. "The greenhouse is wet and dirty, and bar codes rapidly get very filthy. You have a too-high risk of losing a lot of IDs if you use bar codes." Seedlings are still delivered from the lab with a bar code attached, he notes, and the bar code remains with the plant as a backup in case a problem with the RFID tag arises.

Since at least 2002, CropDesign has tracked plants by means of low-frequency (LF) passive RFID transponders coated in epoxy resin, which was intended to protect the circuitry from the greenhouse's high moisture and humidity levels. Temperatures within the facility range from 82 degrees Fahrenheit (28 degrees Celsius) in the winter to more than 100 degrees (38 degrees Celsius) in the summer, and the relative humidity is between 70 and 100 percent—perfect for rice plants, Leyns says, but tough on electrical equipment.

An RFID tag is inserted into the pot of each genetically modified rice plant in CropDesign's greenhouse.

According to Leyns, the unusually harsh conditions have had some unexpected consequences. The transponders' read range has faded by 5 to 10 percent annually, he says, perhaps because hairline cracks in the epoxy may have allowed moisture to seep in. "When we first saw the phenomenon, people didn't believe it," he recalls. "Most likely, humidity is getting inside the transponder, which leads to oxidation." Moreover, he adds, the greenhouse is crowded with machinery that often interferes with the LF signals of the transponders and readers.

To improve performance, CropDesign worked with a technical school in nearby Kortrijk to design and install a high-frequency (HF) system complying with the ISO 15693 standard. The new 13.56 MHz passive transponders will be coated with a PET plastic that Leyns hopes will prove to be more durable than the epoxy. "I'm not naïve," he states, "but since the reading distance [of HF transponders] is much larger, I can afford some losses."

CropDesign is presently phasing in the HF RFID transponders and readers, Leyns says, and the system should be in place by the end of the summer. He says he hopes it will make an efficient system even better.