Updated: Jun 30, 2020
Hull split is around the corner and that means growers are weighing in on how to apply strategic deficit irrigation, mainly to avoid hull rot. Let's deep dive and see how real-time plant-based data together with our irrigation recommendations help growers walk this tightrope by constantly adjusting their irrigation frequency and quantities in order to maintain mild to moderate stress.
AlmondBeat report #8. Here we go.
Creating mild to moderate stress conditions by strategic deficit irrigation during June-July is a common practice which has proven effective in preventing hull-rot. Another benefit is that drier fields are more easily accessible by large harvesting machinery. Significant evidence shows that an effective deficit program can improve split uniformity, help with crop removal and allow for a slightly earlier harvest. The longer those open nuts hang on the trees - the longer they're susceptible to damage. The Risks On the other hand there lies the danger of crop loss due to too much yield-affecting stress. This can also harm trees' health and consequently - next year's yields. And even if you're all-in on applying strategic deficit irrigation, it's easier said than done. Reducing water delivery might not be enough, as the soil may hold excess moisture. In this case, growers would need to wait until the tree dries out its own reservoir in order for it to become stressed through a strategic deficit irrigation.
To Deficit or Not to Deficit? So, how can growers walk the fine line between those two needs? On what basis can they fine tune their irrigation and maintain a perfect balance between yield optimization, production efficiency and trees health?
Knowing Your Trees
Similar to how we approach all of our irrigation decisions during the season, the answer for this dilemma lies in what the trees are telling us. By getting accurate plant stress feedback, as well as tree growth rate and MDS, our growers have a solid foundation on which they can devise an effective deficit strategy, while not compromising kernel fill or future production potential. By looking at the past summary of each block (growth pattern, total stress days, actual irrigation) and how trees' reacted to applied water, growers are able to understand how to induce stress, assess the implication of that stress and are better able to manage the trees' recovery.
In addition, Phytech's irrigation recommendation for each block acts like a northern star, guiding growers every step of the way and giving them the confidence to modify their water delivery (frequency/quantities).
It's like the difference between crossing a mud puddle you didn't measure with a vehicle you don't know, or doing it with your longtime 4X4 truck on a road you've already gone through. There's still some risk, but also a better chance to succeed.
The Science of Balance
With all key data points at their fingers, our customers are not operating in the unknown. Still, deficit irrigation needs constant attention for it to work. 3-4 consecutive stress days might push the trees to the edge. Applying too much stress may cause yellow leafs and even strong defoliation.
Remember that post-harvest growth determines next season's yields. When deficit irrigation works well and almond trees are in good health, you'll start seeing strong vegetation and trunk growth 1-2 days post-harvest until dormancy. Trees that had too much stress may not recover and will stop the yearly growth.
Below is an almond block as seen on Phytech's web interface before, during and after the hull-split period.
It's a good example of how growers are switching to a high frequency/lower quantities plan, while getting constant, direct feedback from the trees (growth rate and water-demand) to support their deficit irrigation strategy.
That's it for now. Keep on learning and stay tuned for our next AlmondBeat report.