IN YOUR ORCHARD
TIME TO CONSIDER
Fall management practices are key to a good start to the 2022 crop. In a drought year with no irrigation and salt management are priorities coming out of harvest. Now is also a good time to gather information and block out time to plan for next year.
In a Nut Shell: • Keep at least adequate moisture in the root zone through the fall (and the winter). • Take soils samples to assess salinity and toxic element (chloride, boron, sodium) risks.
• Manage root zone salt this fall/winter, where needed, if good to decent quality water is available. • Plan to maximize rain-water infiltration with cover crops or volunteer vegetation along with soil amendments. • Consider a fall micro-nutrient spray (boron and/or zinc) if tissue samples show a need. • Take spur or shoot sample(s) beginning in November to look for dormant pests (scale, scab, etc.) • Prep to plan for tough calls in 2022 if rain/snow fall is light this winter.
Planning for the 2022 crop should take tough choices head on. Depending on the water situation for individual operations, it maybe necessary to select which orchard(s) should be farmed or not farmed under different water availability scenarios. The final decisions may not have to be made until the new season starts, but doing the homework ahead of time will make for less stress when crunch time comes. The actual planning is probably a winter activity but information can start to be gathered now. On September 9, 2021, The National Weather Service released a forecast of 70–80% chance of a La Niña winter (2021–22) in the Northern Hemisphere. See forecast at: www.cpc.ncep. noaa.gov/products/analysis_monitoring/enso_advisory/ ensodisc.shtml. Irrigation is critically important through leaf drop to produce a healthy bloom and nut set next year. Moderate to high water stress after harvest, especially in September and October, can significantly reduce flower numbers and nut set next year. Adequately irrigated orchards this fall (and winter) should have the best net return potential next year. How much water do almond orchards need after harvest ? Applying more than 100% ETc will not make more flowers
than the tree would naturally produce (but adding extra water based on a leaching requirement will help with salt management). However, moderate to high water stress will cause trees to fall short of the potential crop for next year. The target postharvest moisture level is -10 to -14 bars stem water potential (SWP) in a pressure chamber readout; that’s low to mild stress based on UC research. Extended periods of moderate to high water stress (SWP of -14 to -30 bars) reduces photosynthesis and sugar/starch production for next year. Some leaf drop will occur when SWP = -20 to -30 bars. Looking ahead to the late fall and the next column, if it’s a dry winter and water is available, winter irrigation can benefit production next year. Buds are never really dormant (the trees look dormant but microscopic changes are occurring in buds through the winter) and high water stress anytime in the late fall/winter can delay bloom, possibly interfering with pollinizer bloom timing. Surprisingly little water (roughly 1”) was needed to return dry almond trees to close to fully irrigated status in recent winter irrigation research by Dr. Ken Shackel (UC Davis). Orchard water use is very low when leaves are off the trees so a small amount of water, compared to in-season use, is needed to keep bud development and timing on track during winter.
4 4
A L M O N D F A C T S
Made with FlippingBook - Online Brochure Maker