mar-apr-2020

Irrigation Water Quality Evaluation Measurements, Units & Relative Risk to Orchard/Irrigation Deliver DEGRE E OF R I SK/PROBL EMS Measurement/Concern Unit None Increasing Severe Salinity (Chemical Water Stress) dS/m <1.1 1.1 – 3.2 3.2< Boron (Toxic Element) mg/l; ppm <0.5 0.5 – 3.0 3.0< Chloride (Toxic Element) meq/l <4.0 4.0 – 10.0 10.0< Sodium (Toxic Element) meq/l <4.0 4.0 – 7.0 7.0< S odium A dsorption R atio (Infiltration) none <3.0 3.0 – 9.0 9.0< Drip Emitter Plugging, Calcium Loss In Soil. (Bicarbonate) meq/l <1.5 1.5 – 8.5 8.5< Practices that have not shown significant water savings: • Removing cropload to reduce water use generally results in increased vegetative growth, which uses more water. • Spraying trees with white mineral products (clay, chalk, etc.) can reduce water stress by a small, but relatively minor amount. • Using anti-transpirants to reduce water loss from leaves has not shown to be effective in past UC research. Untested materials are just that and should be evaluated carefully with some similar rows left untreated for comparison. In order to maximize benefit from available water, develop a water plan for each orchard with an experienced CCA. The stakes are high; one year of severe water stress will mean two years of losses as far fewer flowers for next year’s crop differentiate and develop in water stressed trees this year. Nutrition The key to successful almond nutrition in mature blocks is feeding the crop as it develops. Springtime almond orchard nutrition is focused on getting enough nitrogen and potassium to the trees to maintain adequate leaf levels of those nutrients. Nitrogen Almonds use 68 pounds of nitrogen (N) to produce 1,000 pounds of kernel crop. There are 68 pounds N in the hulls, shells, and kernels removed from the orchard for every 1,000 pounds of kernels in your grade sheets. Annual N budget for each orchard should be calculated from average yield per acre and 68 pounds of N per 1,000 kernels. If you will be short of water this year, this should lower your production by that percentage and reduce N and potassium (K) demand per acre by that percentage. Other sources of N (irrigation water, etc.) besides fertilizer should be subtracted from the total N budget when calculating the fertilizer N budget. Current N input 3 5 M A R C H – A P R I L 2 0 2 0