Harvest is demanding for both orchards and growers. The trees are under immense physiological stress, and what happens in the next several weeks can set the tone for next season’s performance.
Several tools are available to help growers make the most of this critical time by minimizing damage, maintaining tree health, and supporting stronger yields next year.
Tissue sampling and tree reserves
Tissue samples taken now won’t do much to change the outcome of the current crop, but they can offer valuable insight into how the trees are positioned going into dormancy and how they’ll come out of it.
“If you haven’t already, I would definitely recommend grabbing tissue samples now before the end of the season and trying to make some adjustments if growers are seeing some drastic differences, so they the can set themselves up for bloom next year,” said Zach Harcksen, pest control advisor (PCA) with Mid Valley Agricultural Services based in Linden, CA.
Once the trees go dormant, they’ll be working off reserves all the way through bloom until there’s a new canopy.
“If you’re really lacking in certain nutrients during bloom, it’s definitely going to have a yield effect,” Harcksen said.
Late-season sampling allows for a better understanding of any drastic nutrient deficiencies. It also gives growers time to make postharvest adjustments before the trees shut down for the winter.
Phosphite applications after shaking
Shaker damage is one of the biggest risks to tree health during harvest. Whether to the bark or root system, physical injury increases vulnerability to pathogens and weakens the tree going into dormancy. One recommendation for mitigating this stress is a post-harvest phosphite application.
“It’s going to give the tree a little bit of an immune system jump, and it will stay present in the tree all the way until up until spring next year,” said Harcksen.
Trials have confirmed the presence of phosphite in spring root exudates following fall applications. This kind of sustained activity can be especially helpful in helping orchards recover from visible shaker damage.
Strategic postharvest irrigation
There’s a balance between drying down the orchard before shaking and the need to keep the trees hydrated enough to remain healthy.
Depending on the irrigation system, cutting water anywhere from 4-10 days before harvest gets the moisture out of the tree, helping the bark cling more tightly to the tree to protect it from shaker damage. Moist bark has too much movement and can be stripped from the tree.
“So, figure about 10 days without water before growers shake, then the nuts sit on the ground for 3-4 days, then they come in and sweep and let the nuts sit for another 2-3 days, and then come in and harvest,” said Harcksen. “We’re talking about a tree that’s been used to getting watered once a week all the way throughout the season, and then boom, we’re talking the water away for almost 15 days.”
Dual line drip systems offer the most flexibility because a small pulse of water can be applied directly after shaking—not enough to rehydrate the tree and give it a full irrigation, but enough to spoon feed the tree, help it along, and get some moisture back into the ground.
“Maybe three hours, five hours max,” said Harcksen, just to get the orchard back to it’s normal functioning as soon as possible.
This approach requires a well-functioning system. Holes in the lines or poor distribution could result in wet nuts, which would only slow down drying.
Micro-sprinklers and full-coverage systems are less suited to this kind of short, targeted irrigation. Sweeping sooner and conditioning may be a better way to accelerate drying and resume irrigation as quickly as possible.
“It’s not a blanket approach,” Harcksen said. “You’ve got to have the right setup, and you’ve got to be careful, but when it’s done correctly, it can really help an orchard.”
Cleaner crops and conditioner benefits
Some huller-shellers are charging by incoming weight rather than processed weight in order to reduce foreign material delivered with the crop. Newer equipment, like conditioners, are becoming highly recommended in order to serve a two-fold benefit. When nuts are swept and left to dry, a conditioner will not only remove the leaves, sticks, and other foreign material, it will also neatly lay down the crop where it gets the most exposure to sunlight, thus speeding up drying time.
“You’re delivering a cleaner crop and probably paying a little less, because you’re not sending in all that foreign material,” Harcksen said. “It also makes your huller a lot happier.”
This also means a quicker return to regular orchard operations, which can make a noticeable difference in how trees finish out the season.
No one-size-fits-all solution
There’s no blanket approach, but these are the types of conversations growers should be having with their PCAs during this time of year.
“It’s important to ask, ‘How are we going to keep my orchard healthy during this high-stress time,’” said Harcksen.
Every operation has its own system, challenges, and timing, but smart decisions during this critical window can set up orchards for a stronger recovery and a stronger bloom.
Main image: A shaker during almond harvest. Photos: Crystal Nay, Modern Ag Media
