I have been emailed a few questions in regards to calculating the amount of nitrogen in a gallon of Urea Ammonium Nitrate (UN-32 or UAN-32). Since UN-32 is widely used to fertilize/fertigate almonds, it is necessary to know how much is being applied per application.
1 gallon of UN-32 weighs 11.02 pounds. 32% of the weight is nitrogen – hence the “32.” This roughly equals 3.4 pounds of nitrogen per gallon, or 55 ounces.
So, following the guidelines suggested by Brent Holtz (UCCE San Joaquin),when fertigating 2nd leaf trees with UN-32, at 110 trees/acre, no more than 4 gallons should be used in a single application.
I hope this helps.