WCN Almond Dust Control 903

(originally published July 2017)

Good, thorough dust control has many benefits from reducing  topsoil erosion, to mite control, to safety. 

Dust control is not just at harvest.  It goes through the entire season, according to David Doll, University of California Cooperative Extension (UCCE) farm advisor for Merced County.

“I think many people focus at harvest because of how much dust you throw out just through the harvesting process,” Doll said, but if good practices are employed earlier, it will also reduce dust at harvest, which is better for the trees.

Franz Niederholzer, UCCE farm advisor for Colusa, Yuba, and Sutter Counties, said, dust control is an environmental, safety and even a pest control issue.



Dust is kind of like spray drift when it’s close to

roadways, Niederholzer said. 

“Nobody wants to be throwing dust out in the road and risking collisions out on the county roads and highways,” Niederholzer said, adding dusty orchard roads can also be a hazard to workers and impact visibility.

     Doll agreed safety is another factor, and a good reason for dust control.

Gabriele Ludwig, director of sustainability and environmental affairs for the Almond Board of California, said, as acreage has grown, the visibility is really something to think about. 

Growers should be thinking about who and what are around when they’re harvesting, Ludwig said.  Also, be mindful of nearby roadways, neighbors, other crops with crews working, and consider what you as a grower can do to try and minimize dust, particularly in those situations, she added.

If harvesting near a busy road, consider placing traffic signs to warn motorists of harvest activities.

Maintaining Orchard Roads

Maintaining orchard roads with water, oil and different salt solutions will help reduce dust, Doll said.

Scott Hunter, part of Hunter Farms in Livingston,

California, does dust control on his orchard roads and there are several dust reducing agents available, he said.

     “We use a product called Dust-Off, which is actually food grade.  It’s a good product,” Hunter said.

     Some growers are using magnesium chloride for dust control on orchard roads, Niederholzer said.

      “Some materials are latchkey where there’s an applicator that comes and applies the product,” Niederholzer said, and others just use water.

“Dust control on roads is also part of a mite management program, and everybody wants to keep mites under control.  So, keeping dust under control is double duty.  Dusty trees tend to be where mites show up first,” Niederholzer said.


“The dust that we create in an orchard is just going to consolidate, it’s going to settle on the trees and eventually continue to build.  And when a tree becomes dusty, it becomes stressed, and the stress brings in mites,” Doll said.

Mite damage has what Doll calls a hangover effect. 

“It doesn’t necessarily impact this year’s crop as much as it can impact next year’s crop because you’re defoliating the trees and then the tree will release, and when it releases, it reduces the number of buds that will develop into fruit buds for the next year,” Doll said, adding dust control is one method for controlling mites.


Orchard Floor Management

Good dust control practices also help prevent problems with erosion, Doll said.

“I’ve been in more and more orchards where you’re seeing the berm that people plant the trees on has been eroded over time.  And that erosion is usually due to the harvesting practices—the multiple times they’re sweeping, the multiple times they’re picking up in these orchards,” Doll said. 

Reducing compaction is an important way to reduce dust.  Doll advises growers to avoid driving through the orchard when soils are wet to prevent ruts from forming.  Ruts have to be graded prior to harvest, and grading creates more dust, he said.

     Cover crops can reduce compaction and dust.  While cover cropping is not necessarily convenient with other practices, it does help reduce compaction and dust in the field, Doll said.

     Driving on a bare orchard floor will kick up more dust than an orchard with a cover crop.  But at harvest, cover crops can be a struggle and a challenge to manage, Doll said.

Equipment Calibration

Equipment calibration is a critical component to dust control, Doll said. 

Don’t set the heads any lower than necessary.  Wire tines can be set as high as 0.5 inches off the ground and still do a good job sweeping.  If they are set too low, the sweeping head will move an excess amount of dirt into the windrow and substantially increase dust from the pickup machine.  Using wire tines on sweeper heads without rubber flaps will also help reduce dust.

“You don’t want to go too deep in harvesting,” Hunter said, adding when you’re sweeping, you don’t want to go too slow either. 

 Good orchard practices and having a good orchard floor is probably going to be the biggest thing that you can do to reduce the dust because it allows you to go through the field faster, Hunter said.

     “It’s like you’re in a car.  If you’re getting from point A to point B without traffic, you’re probably going to have less emissions than if you were sitting in traffic for an extra hour,” Hunter said.

     “If you can go through the field at a good pace, and get a large percentage of the almonds without having to go back and slow down, and have to really sit there and turn the blower up all the way, and blow around the berms, you’re able to go much faster, which would equate to much less dust,” Hunter said.

Hunter does about 50 percent of his harvesting at night.  Harvesting at night means there’s generally less wind to move the dirt, and it settles back down, he said. 

“It helps us, too, to schedule people.  There’s a lot of benefits to doing it at night,” Hunter said.

Ludwig also suggested using the trees to capture some of the dust by blowing into the orchard instead of out.

Plan passes and travel direction so that dust is directed away from roads, homes and sensitive locations like schools, hospitals and day-care centers, Ludwig said.   

New Equipment 

There is new equipment available that is more effective for managing dust at harvest, Doll said.

     Ludwig agreed investing in new equipment that’s been engineered to reduce dust is another way to reduce dust. 

There are two ways to do this, Ludwig continued.  One is actually go out and buy reduced dust equipment, or two, use the EQUIP program through United States Department of Agriculture (USDA)/National Resources Conservation Service (NRCS). 

Eligible equipment is limited to specific harvesters from demonstration trials at Texas A&M that were found to reduce particulate matter by at least 30 percent.

This isn’t a cost share program for directly buying equipment, Ludwig said.  Instead, qualified growers will receive $10.52 per acre for up to three years for use of qualified harvesters.

“Part of the reason they did that is there is quite a bit of custom harvesting going on.  So, this allows a grower who’s not doing his or her own harvesting to choose to work with a custom harvester who has low dust equipment, and then get some funding from NRCS,” Ludwig said, adding it also encourages custom harvesters to invest in the reduced dust equipment.

Applications are accepted year-round through your local NRCS office.  Growers considering this for the current year’s harvest should contact their local office as soon as possible.

For more information on dust control, go to www.almonds.com click on grower, then harvest.


By: Kathy Coatney