mar-apr-2020

TIME TO CONSIDER This time of year, a wide range of tasks, all requiring careful attention, including irrigation, fertilization, and disease, insect and weed management, need to be done to deliver a high-quality crop. In 2020, spring looks to be especially challenging as crop potential seems good, but surface water availability is limited in many areas and a warm winter may accelerate insect and mite pressure. Irrigation Nothing is more important than adequate, effective irrigation to produce the best crop possible. However, as of early March, surface water allocations are 15 to 50 percent of contract in many almond growing areas in the Central Valley Project. To help growers and CCAs do the best irrigation job possible with limited water, a recent UC ANR publication on managing almond irrigation under low water availability is available for download at anrcatalog.ucanr.edu/pdf/8515.pdf. While it’s too early to know what the final surface water allocation(s) will bring, it’s not too early to review options. Many readers may already have run through the following, but here are a few practices/lessons learned for maximizing water to the crop. • Maintain your irrigation system(s) to make sure you are evenly applying what you think you are applying. See detailed information at micromaintain.ucanr.edu . • Run irrigation systems when evaporation risk is low, especially for sprinkler irrigated orchards. Evaporation loss from wet soil surfaces on hot, dry days is as much as 25 percent of applied water, water you paid to pump and is not plant available. This loss percentage should be less in spring but establishing the practice of night irrigation early in the season should set you up for more savings in summer. Finally, irrigation sets should be longer than six hours to reduce percentage of total water lost but not so long as to produce runoff. • Take irrigation water samples (well and surface water) through the season to check water quality. Salinity, toxic elements and/or carbonates in irrigation water can potentially harm irrigation delivery/orchard health. These levels can change with time and water source. Don’t assume that surface water is clean, as well water and runoff can end up in canals in dry years. The information in the irrigation water quality table in this article shows the general degree of risk/problems associated with different water quality measurements. • If water availability is very tight, consider reducing irrigation on older blocks planned for removal and shift water savings to younger blocks. Loss potential in young orchards is the greatest of all plantings as vegetative growth and future yield potential are delayed with water stress. It takes two years of full irrigation to return an orchard to pre-stress production. If the plan is to remove a block within two to three years, consider removing it this year and using the saved water to keep younger blocks as healthy as possible. Almond orchard in March. Photo Credit: Franz Niederholzer. IN YOUR ORCHARD 3 4 A L M O N D F A C T S