Its 1/2 lb of AS per gallon. 1/2 lb of N would be about 2.5 lbs per gallon and that rate is hard to get into solution and extremely phytotoxic.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738