Blue Diamond Almond Facts July-August 2021

IN YOUR ORCHARD

TIME TO CONSIDER

In a nutshell: • Kernels gain weight through July. Where possible, maintain full irrigation (100% ET) up to orchard dry down for harvest for best kernel weight and orchard yield at harvest. • Postharvest irrigation is key to future production. As soon as possible, get water back on harvested trees (but not on drying or windrowed nuts). • Proper harvest timing reduces worm and trunk damage. Shut down shakers ASAP if trees don’t shake clean. • Where needed, control navel orangeworm and mites. When spraying, drive slowly (2 MPH) and use sufficient water volume (gallons per acre) to get good coverage. • Make sure nuts are dry (kernels at or below 6% moisture, hulls at or under 12%) when picked up. Don’t stockpile wet nuts.

Stage 2C hull split: when all nuts are at least this stage, timely harvest can mommence. (UC IPM photo source)

Irrigation: Kernels gain weight until just before harvest. July water stress will reduce kernel weight. Measured with a pressure chamber, the stress level threshold is -15 bars, with stressed trees (-15 to -20 bars) resulting in lighter nuts through shrivel. This reduction in kernel weight can be up to 20% of what fully irrigated kernels weigh. So, as much as possible in a drought year, maintain full ET irrigation from the end of hull split (90% of nuts split to stage 2C hull split) until just ahead of shake. Too much irrigation will not benefit trees and may delay maturity and shake timing. A free, helpful publication on pressure chamber use in almonds (and walnuts and prunes) is found at: anrcatalog.ucanr.edu/pdf/8503.pdf.

• Take a hull sample for boron analysis.

• Take “report card” samples:

o July leaf samples for nutrition program check (include chloride & sodium) o 500 nut harvest sample/variety/block to check for pest damage

As soon as possible, get water back on the orchard after shaking. Limiting water stress at harvest reduces early leaf drop this fall and the risk of future yield loss. Maintaining nearly full to full ET following harvest is critical to orchard health this year and flower bud differentiation for next year. Target stem water potential is -10 to -14 bars in the postharvest period, a target that works for preharvest, too. Is there a time to save on water between now and leaf drop ? No. Adequate to good moisture levels in the orchard in July will deliver the heaviest kernels possible this year while good postharvest irrigation will help set up future crops.

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A L M O N D F A C T S

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