Rings of deep green grass may surround the spots. The surrounding grass no longer mats down, and may be either dark green, contain other strawlike patches or have no spots at all. Dogs have been in the area and urinated. The nitrogen in the urine may either immediately, or some time later encourage rapid growth of affected grass which results in the dark green ring. Depending on the concentration of urine salts, grass may discolor and die off.
Lawns suffer the most damage from dog urine in hot, dry weather where it sits without washing away.
The simplest remedy is to keep dogs off the lawn. When this is not possible, water affected areas thoroughly to help wash aware urine. This will not eradicate the damage, but will help with the initial discoloration and may stave off lawn death. If the urine is washed away, the surrounding grass will quickly fill in the damaged areas with new, undamaged growth. Could be urine damage.