The Floras, who have spent years custom harvesting almonds in California’s Central Valley, know all too well what a dusty job and at times—a public relations challenge—it can be.


That’s why several years ago they began designing and manufacturing machinery to help clean up the harvest.


Operating as the Exact Corp. of Modesto, Calif., the Floras have marketed their low-dust nut sweeper for the past seven years.


Recently, the firm showcased its new low-dust almond harvester in an orchard managed by the Bavaros near Farmington, Calif., to great reviews.


The harvester has been six years in the works, says Doug Flora of Exact.


The company had prototypes two years ago that didn’t produce the dust plume, but the earlier versions didn’t have the ground speed growers would want, he says.


The latest version can move down tree rows at the same speed as conventional harvesters—4 mph—and still produce much less dust.


“We’re impressed, just like everything these guys do,” says Joe Bavaro, who farms with his father, Nick, in Stanislaus and San Joaquin counties. “We’ve heard a lot of good things and we wanted to see it run, and there’s no place better than under your own conditions.”


“I love the harvester,” Nick Bavaro added after he saw the machine in action.


Almond harvesting 101


Almonds are harvested in three steps.


A shaker grabs the tree trunk and shakes the tree, causing the nuts to fall on the ground.


A sweeper moves the nuts into a windrow in the middle of the tree row, where the nuts typically dry for seven to 10 days.


A harvester then picks up the nuts as well as dirt and other material on the ground.


Once in the harvester, the debris is separated from the nuts by a 15,000 cubic-feet-per-minute air stream. The nuts, being heavier, drop to a conveyor for eventual transport to a nut buggy.


Dust and other lighter material are carried by the air and discharged out the side, creating a plume of dust frequently visible for six to seven tree rows over.


And it’s this dust plume that has drawn public outcry.


Locking up dust


The Exact E4000 Harvester doesn’t use those large volumes of air to remove foreign material, Flora says.


Instead, the plant debris and dirt that are picked up are conveyed into an air-lock chamber, where much of the heavy material drops onto another conveyor. It is then spit out the side.


A small amount of water from an attached 185-gallon tank is misted onto the fine dust en route to the scrubbers. The scrubbers resemble the patented brushes used on Exact’s low-dust sweeper.


The moist dust forms little mud balls that coat the brushes and are periodically flicked onto the ground.


Visibly missing are the plumes of dust.


Flora estimates that by combining their low-dust sweeper with their low-dust harvester, growers can conservatively reduce visible dust by at least 50 percent.


Putting low-dust harvesters to the test


Brock Faulkner, a research assistant professor with Texas A&M University’s Department of Biological and Agricultural Engineering in College Station, wants to verify those observations.


He has a conservation innovation grant from the Natural Resources Conservation Service and funding from the San Joaquin Valley Air Pollution Control District to study low-dust almond harvesters.


The research will compare production of PM10 and PM2.5 dust particles from conventional and low-dust machines.


PM10 particles are 10 microns or less in diameter. By comparison, a human hair ranges in diameter from 40 to 600 microns. PM2.5 particles are four times smaller than PM10 particles.


According to the U.S. Environmental Protection Agency, exposure to high concentrations of PM10 and PM2.5 particles can cause respiratory problems and aggravate existing cardiovascular and respiratory diseases.


Until 2008, the Environmental Protection Agency categorized the San Joaquin Valley as a non-attainment area for PM10s.


The area has since come under attainment by following rigorous dust-reduction procedures. But the San Joaquin Valley Air Pollution Control Board always is looking for ways to further reduce dust production.


In early October, Faulkner pitted the Exact E4000 harvester against a conventional one in a Kern County almond orchard.


Flory Industries of Salida, Calif., has said it would participate in a similar trial in 2011, Faulkner says. Weiss McNair of Chico, Calif., another harvester manufacturer, also may be involved next season, although he says he has yet to hear from the firm.


Data from the Exact trial won’t be available until early 2011, Faulkner says. Results from the 2011 trials won’t be available until early 2012.


The value of dust reduction


The Exact E4000 is priced about $30,000 more than a conventional almond harvester, Flora says.


“Now the questions is, what is the value of that [dust reduction]? For some people, it’s very, very high if they’re farming near a roadside or residential area,” he says.


“Not blasting dirt on pollinator trees, better food safety. I think there are lots of things we can list as benefits. Ascribing a value to that is different with everybody,” Joe Bavaro says.


Contact Vicky Boyd at vlboyd@att.net or (209) 571-0414.