jul-aug-2020

IN YOUR ORCHARD TIME TO CONSIDER Harvesting and hulling a record crop is a challenge. Equipment and crews need to be prepared for the long haul from Nonpareil through the late pollinizer harvests to deliver a quality crop while protecting orchard health and setting up the trees for next year. Then there is the COVID virus wild card. Irrigation Now, as much as any time during the season, careful irrigation is critical to nut yield per acre and grower income. Almond kernels continue to gain weight through the summer until just before trees are ready to shake. Flower bud differentiation for next year’s crop begins in August. Except for harvest dry down, sustained moderate to high water stress in July and August means smaller (less dry weight) kernels at harvest. Maintain stem water potentials, measured with the pressure chamber, above -15 bars. Research has shown that water stressed trees (-15 to -20 bars) produce nuts that are up to 20 percent lighter (due to shrivel) than trees averaging above -15 bars. Bottom line is that between the end of Strategic Deficit Irrigation (SDI) for hull rot management and harvest irrigation cut off, trees should receive full ET or as close as possible. Excessive irrigation will not help tree performance and may delay crop maturity and shake. Free, helpful publication on pressure chamber use in almonds (and walnuts and prunes) is found at: anrcatalog.ucanr.edu/pdf/8503.pdf. As soon as possible, get water back on the orchard. Innovative growers are moving nuts into adjacent rows or into row middles soon after shaking to complete drying while water is returned to a portion of the orchard without getting water on the drying nuts. Maintaining 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. The key is to avoid extended periods of moderate to high water stress that will cause partial defoliation. Harvest Timing In a record crop year with significant NOW pressure, shake timing is critical to a successful harvest and also long-term health and productivity of the orchard. Timely harvest will significantly reduce the exposure of nuts to NOW egg laying and subsequent infection. Shaking does not remove or harm eggs or larvae already on the nuts. The crop is ready for harvest when 100 percent of the nuts are at least at Stage 2C (see photo below). However, the trees may not be ready to shake at the same time that the crop is ready. To see if the orchard is ready to go, test shake representative trees across the orchard, especially focusing on wetter areas (low spots, etc.) where the trees maybe more vigorous and nut maturity delayed. Be ready to wait on harvest if trees don’t shake clean without an excessively long, hard shake. An orchard can be almost ruined (see photo) in a few hours if the trees are not ready to shake and an operator is not supervised carefully. If the trees shake clean without extended, hard shake, a safe harvest can start. 3 4 A L M O N D F A C T S