I have an 13½ year old dog who is almost blind. She is still able to make her way outdoors to go potty but due to her age and poor eyesight, doesn't get very far before she squats down: essentially, off the porch, past the flowerbed, turn right. The upshot is that one spot in my yard gets "watered" a lot.
Since that spot is right by the porch, if I'm dining outside or just sitting enjoying the evening sun, I frequently get hit with a blast of stale dog urine. This is especially bad during the summer months because (a) I'm outside more, and (b) we get warm, dry summers here which means the urine doesn't get washed away quickly (even running the sprinkler in that area more than usual).
Is there anything I can do to reduce or eliminate the smell of her urine?
(My other dogs are grazers so any answers involving chemicals should take toxicity into account.)