static design loads range from to 70-100 lb/ft3-ft of depth. The most mmon liquid fertilizers are 28-0-0 or UAN solution at 79 lbs/ft3 (10.6 lbs/gal) and 10-34-0 at 85 lbs/ft3 (11.4 lbs/gal). Check with the manufacturer for the density of specific fertilizers, or design for the highest density. 2.