Oct. 2005 Vol. 2, Issue 4

Test device measures dust from almond harvesting

By Dan Bryant

Western Farm Press

Reprinted with permission of Western Farm Press

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  While the California almond industry pursues various ways to reduce the dust associated with the crop, a group of engineers at the University of California, Davis is testing equipment designed to monitor the amount of particulate matter released during harvesting.

One of them, Ken Giles, a professor in the biological and agricultural engineering unit, recently described the experimental device during a regional almond day program at Coalinga. Basically a sensor originally designed to measure power plant smokestack emissions and attached to an almond harvester, the unit uses a pulsing light beam directed across air-flow tubes as the nuts are picked up.

It indicates the amount of dust interrupting the light, and the data is saved in a computer. Termed an "in-line sensor," it serves the same purpose as equipment used to measure emissions from motor vehicles.

"There is information that says harvesting is one of the most dust-intensive operations," Giles said. "One of the problems in monitoring air quality is it is very, very time consuming with setting up and weighing filters placed around a field. It can take years to collect data.

"Our purpose is to provide something more practical and efficient for growers and to help machinery manufacturers develop new machinery. Growers know there’s dust out there, but we are beginning to get some numbers to apply to it."

A harvester is driven through an almond orchard as part of research being conducted by UC Davis scientists to monitor the amount of particulate matter released during harvest. (Photo courtesy of Ken Giles, UC Davis)

He went on to say they looked for something "off the shelf," a commercially available sensor, without having to "re-invent the wheel" from scratch. Collaborating with Flory Industries, the UCD team attached the sensor to a Flory 850 PTO nut pick up machine and tractor and fitted a computer to collect data. Part of the challenge, Giles said, was adapting a device designed for stationary use to a mobile application.

Variables affect dust

In limited trials last year, the equipment showed that several variables in harvesting operations, including ground speed, machine adjustment, soil type, and yield intensity, affect the amount of dust generated. This coming season they plan to continue collecting data with a separate, trailer-mounted device operated near the pick up machine.

"It may be that in some parts of an orchard, reducing speed might have a big effect on reducing the amount of dust generation," he noted, adding that, on the other hand, reducing speed and prolonging the operating time may cancel out that benefit. "We are looking for some balance between them."

He said this year they plan to investigate windrow preparation, the amount of spider mites and leaves present, and perhaps nighttime operations, while they collaborate with other scientists observing irrigation practices and use of polyacrylamide compounds to reduce dust.

Support for the project has come from the Almond Board of California and USDA.

Air hoses pull in samples of air from harvester to measure dust levels as part of research being conducted by UC Davis. (Photo by Ken Giles, UC davis)