Almonds should be harvested as soon as possible after they have matured to avoid quality loss and to minimize exposure to navel orangeworm and the subsequent potential for aflatoxin contamination.
After the crop is mechanically shaken to the ground, the nuts are raked into windrows and allowed to dry naturally, ideally to a hull moisture content that does not exceed 12%, or a kernel moisture content that does not exceed 6%, which can take anywhere from a few days up to two weeks.
A harvest sample taken after shaking and before the crop is windrowed will provide a progress report of that season’s IPM program, and will indicate what pests are in the orchard, which will, in turn, help determine the management activities for the next year.
Pickup machines sweep the windrows into carts or trailers for transportation to a huller/sheller facility. With the large crops of recent years, it has become more and more common for almonds to be stockpiled, either in the orchard or at the huller/shellers. To avoid insect damage, stockpiles should be monitored and fumigated if necessary.
Reducing Dust at Harvest
Improving air quality in California, especially in the San Joaquin Valley, is a major issue for all residents. Sweepers and pickup machines can create a significant amount of airborne particles (PM10). Almond Board of California–funded research has developed numerous methods growers can use to reduce dust at harvest, such as changing sweeper head height, reducing the number of blower passes, using metal tines, and reducing pickup machine speed. In addition, equipment manufacturers have made changes to the sweepers and pickup machines to reduce the amount of visible and PM10 dust emitted.
Everyone involved in the growing and harvesting of California Almonds should be aware that dust affects all who are present at harvest, including workers, neighbors and the community.
Below are four quick steps growers and operators can take to reduce harvest dust.
Maintain clean orchard floors.
Blow into the orchard when working near field edges and use the trees and their canopies to naturally filter dust.
Set sweeper head height to optimum level and use fewer blower passes when possible
Reduce harvester ground speed to allow more time for gravity separation.
For a full listing of dust reduction strategies, download the Almond Board’s Managing Dust at Harvest Quick Guide, available in English and Spanish.
Maintaining California Almonds that are stockpiled requires careful management to avoid contamination and damage that can reduce kernel quality and lead to food safety concerns. The key issues in stockpile management are moisture and temperature.
The following documents provide guidelines for managing moisture in the stockpile and minimizing concealed damage that can result from harvest rains and excess moisture.