A high-quality California almond crop is a year-round process which can increase grower returns, enhance food safety, and strengthen the industry’s environmental footprint.

University of California (UC) almond specialists Joe Connell and Bruce Lampinen, UC agricultural engineer Ken Giles, have a roadmap with directions to produce and harvest a safer and cleaner almond crop. The trio shared their findings during the Almond Industry Conference in Modesto, Calif., in December.

The year-long process starts in the winter months, says Connell, UC Cooperative Extension almond farm advisor in Butte County.

“Good orchard management is an ongoing process to ensure the orchard floors are in good shape at harvest,” said Connell who has 30 years of almond experience. “The first step toward a clean harvest is a good job of winter sanitation.”

Connell’s prescription for winter sanitation includes clean orchard strips through contact or pre-emergence weed control. Non-tillage strip weed control provides improved orchard access all year; a firm orchard floor with less dust and a weed-free surface for harvest; reduced tree trunk damage, crown rot, and compaction; improved water penetration in most soils; and higher leaf potassium levels.

“A pre-harvest herbicide application to the row middle helps keep the orchard floor clean and promotes rapid nut drying,” Connell explained. “A clean surface enhances food safety and nut quality.”

Organic weed control is more of a challenge. Propane flamers used down the strips work well with small weed seedlings only. The flame heat should kill the weed, not burn anything.

Another key to orchard sanitation is blowing mummies to the row middle and chopping up to reduce Navel orangeworm problems and avoid potential aflatoxin issues at harvest. Avoid making ruts in wet soil during the winter so harvest equipment can efficiently and effectively move across the orchard floor, Connell says.

Timely and proper brush removal is also important. Brush burning is not allowed in many areas of the San Joaquin Valley due to air quality issues. Chipping and shredding brush are effective.

Keeping vertebrae animals out of orchards also protects the crop. Growers should minimize animal entry into the field, Connell says. Controlling squirrels and other rodents removes reasons for the entry of animal predators including coyotes. Contamination by wildlife closer to harvest increases food safety risks. Consider the field proximity to livestock operations.”

Composted manure as a fertilizer in orchards is a sensitive issue. Connell advises against manure use in almond production. If manure is used, apply the manure in the fall after harvest with soil incorporation followed by watering with rainfall or irrigation. Make sure the manure is well composted. If non-tillage weed management is used, Connell says avoid manure use in the orchard.

Another clean and safe practice is to sanitize harvest equipment and the huller before harvest. Unused equipment draws varmints which can leave droppings and contamination behind. Also, know the source of surface irrigation water. Know where the water came from upstream. If there is any potential for contamination, a water test is a good idea that can help guide treatment if necessary.