Depends on which grade. I see lots of unpolymerized urea in that label. My requirement is for at least 70% polymerized, in the mix it is not intended as the "green um up". That is what the ammonium and nitrate nitrogen is for. The CRN is just so the lawn holds if I am not exactly on schedule.
Were you applying 1 lb of N per acre in 20 gallons or was that 43 lb of N in 20 gallons? With what I use, the latter would be almost undiluted 28-0-0. Well irrigated grass can take pretty high concentrations of just 28-0-0. It gets different when P, K, and micronutrients are in the solution because that affects the salt index.
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