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After a Hard-Working Harvest, Trees Need Water to Remain Healthy

One of the key factors to maximizing potential yield next crop year is making sure your trees receive a good post-harvest irrigation shortly after harvest.

9/24/2020

Tree health photo.jpg

Growers have a lot to think about leading up to and during harvest – prepping the orchard floor, timing the first shake in relation to hull split and achieving optimum moisture content during drying are just a few of the many important factors growers will consider from July to October.

Even as this season’s bounty is being harvested, the foundation for next year’s crop is already being developed through fruiting-bud differentiation. The period from July to October, in normal years, is when floral buds develop and the next year’s crop yield potential is set. The principle is simple: more buds = likely more flowers = likely more almonds. 

Many factors can affect crop yield, such as pollination, weather, and nutrient management decisions. But this year, especially, with a record projected crop on the way, one key practice growers should implement to maximize yield potential is optimized post-harvest irrigation. Because growers typically stop irrigating in the weeks leading up to harvest, their trees can be rather dried out come late September and early October.

“The sooner you can get water back on your trees, the more you’ll be able to support tree health,” said Sebastian Saa, Ph.D., associate director for Agricultural Research at the Almond Board of California (ABC). “We know next year’s buds already are on the tree – water reduces the stress on the tree and therefore allows those buds to further develop.”

One way for growers to think of post-harvest and late-season irrigation is that they are “paying it forward” for next year’s crop. During this critical time, trees’ water needs are significant and severe water stress can drastically affect bloom, fruit set and yield.

Saa said growers who have self-compatible varieties may have more flexibility when it comes to post-harvest irrigation. Because there will only be one harvest per block in self-compatible orchard configurations, growers will not necessarily need to wait for the harvest of the pollinizer to irrigate again. Similarly, Saa also said that off-ground harvest (catching the nuts and drying them outside of the orchard) or semi-off ground harvest (catching them and re-allocating them to the middle of the row) also may provide flexibility when it comes to post-harvest irrigation.

One key resource available to help growers better understand irrigation management – both post-harvest and year-round – is ABC’s 
Almond Irrigation Improvement Continuum. This resource, developed by the Almond Board in partnership with many trusted and respected technical experts, provides a wide-ranging look at a grower’s site-specific irrigation system with the goal of improved efficiency and effectiveness. In the Continuum, growers and irrigation experts will find a step-by-step explanation of irrigation management and scheduling practices related to the following concepts:

  • measuring irrigation system performance and efficiency,
  • estimating orchard water requirements based on evapotranspiration,
  • determining applied water,
  • evaluating soil moisture, and
  • evaluating plant water status.

Tom Devol, ABC’s senior manager of Field Outreach and Education, is available to help almond growers reach their goals of increased water efficiency. Devol and his team can meet growers in-person for in-orchard consultations to discuss irrigation systems, address challenges, and share ABC’s print and online irrigation tools. To schedule your own irrigation consultation, email Devol at tdevol@almondboard.com or call (530) 570-5558.

More post-harvest irrigation information
More information about the impacts of water stress on fruit bud development in relation to growing regions and varieties is available in the University of California Agricultural and Natural Resources publication 8515, “Drought Tips: Drought Management for California Almonds,” found at Almonds.com.