jan-feb-2021

IN YOUR ORCHARD TIME TO CONSIDER This will be an interesting year with the uncertainty of surface water availability and nut pricing. However, much of these concerns are beyond grower control. Careful focus on on-farm activities should set growers up for the best possible yield and quality for the coming year. Activities to consider this winter include completing orchard sanitation for navel orangeworm (NOW) management, quality bee rental/care, frost protection, and selection/timing/delivery of bloom fungicides. Irrigation The most important growing issue facing many almond growers this year will be water: availability and quality. So far, rainfall in the Sacramento Valley where I work is about 30 percent of normal and Shasta Lake levels are about 70 percent of average. All irrigation decisions should be made on a site specific basis with as much information as possible available to help with decisions. What are the salt levels different root zone depths ahead of bloom ? What is the quality of available irrigation water ? Generally, it is a good idea for orchards to have a full profile coming out of winter, even if moderate quality groundwater is used to fill the profile. Any rain between now and spur leaf fill (when the trees start to use water) will push salts deeper in the root zone and away from the most active roots near the soil surface. The following table presents irrigation water quality guidelines taken from Dr. Phoebe Gordon’s 201 9 UC Almond Short Course talk. *If the lab reports in ppm Cl, divide that number by 35.4 to get meq/l. Water Quality Measurement (reported units) No Growth Restriction Increasing Risk of Growth Restriction Severe Risk of Growth Restriction Salinity, ECw (dSm) <1.1 1.1 - 3.2 >3.2 Chloride,Cl- (meq/l)* <4.0 4.0-10 >15 Sodium Adsorption Ratio, SAR (no units) <5.0 3.0 - 9.0 >9 Boron, B (ppm) <0.5 ppm 0.5 - 3.0 >3.0 4 4 A L M O N D F A C T S