California Ag Network

Tag: Nut Production

  • September Orchard Tasks – Pistachios

    Pistachio harvest ended earlier than usual this year, but growers should not stop irrigating their orchards just yet. The early finish creates a longer post-harvest period before trees enter dormancy, making proper irrigation especially important.

    Research by Daniele Zaccaria, Mae Culumber and Anderson Safre of the University of California Cooperative Extension indicates that pistachio trees continue using water after the nuts have been removed. Although harvest is complete, evapotranspiration—the loss of water from the soil and through the trees’ leaves—continues until the trees become dormant.

    Because the post-harvest season will be longer this year, growers should continue monitoring their orchards’ water needs. Stopping irrigation too soon could place unnecessary stress on trees as they prepare for next season.

    However, the researchers suggest growers may be able to conserve water through carefully timed deficit irrigation. This practice involves applying less water than the orchard would normally use during selected periods. When managed properly, deficit irrigation may reduce water use by about 20% with little to no effect on the following year’s harvest.

    The key is timing. Growers should consider orchard conditions, soil moisture and the trees’ water needs before reducing irrigation. An early harvest does not mean water use has ended, and post-harvest management can play an important role in supporting the next crop.

    Read more about the research in the September issue of Pacific Nut Producer Magazine.

  • September Orchard Tasks – Almonds

    Although almond harvest may be wrapping up, the work needed to prepare orchards for next season has already begun. Post-harvest priorities include monitoring for disease, irrigating trees, pruning and managing pests.

    Brent Holtz with the University of California Cooperative Extension advises growers to watch for red leaf blotch and rust. Bright orange spots on leaves may indicate red leaf blotch, while orange and black spores can be signs of rust. This year’s warm March appears to have increased the severity of rust, making it important to avoid irrigation practices that keep orchards humid for extended periods.

    However, growers should not stop irrigating altogether. Water should be applied as soon as the harvested nuts are removed from the orchard floor. Dr. David Goldhamer, emeritus irrigation specialist with UC Davis, says almond trees can use up to 11 acre-inches of water after harvest if their leaves remain active. Proper post-harvest irrigation can also help move salt below the trees’ root zone.

    Growers can also begin pruning mature orchards immediately after harvest instead of waiting until dormancy. Pruning early gives wounds time to heal before rainfall, reducing the risk of fungal diseases. While studies indicate pruning does not significantly improve almond yields, it remains necessary to provide enough space for orchard equipment to pass between trees.

    Fall is also a good time to manage gophers, ground squirrels and mice. Baiting or fumigation can help control ground squirrels before they enter hibernation. Growers should also look for pieces of almond shells left in tree crotches, which may indicate mouse activity.

    For more information about post-harvest almond orchard management, read the full article in the September issue of Pacific Nut Producer Magazine.