Valsdad-
"It's usually about 20% humidity here, so the poo dries up quicker than it can burn the lawn I think. Lotta times it's so dry it just crumbles if it gets stepped on.
Dry enough I'll spread it around landscaping plants...................screw those Job's tree spikes! free nitrogen from the pooches."
I believe you are correct on the humidity /dog poop thing. It's pretty wet and humid up here. And it snows, which means if I miss a few winter turds, they produce dead spots in the lawn come spring.
To expand on my earlier post ( my wife was rushing me to go hiking) . I have had male Lab or mixes for over 40 years. Bare spots everywhere they pooped. So much for the "female urine" thing. 16 months ago I had a nice evenly green lawn, having been dog-less for over 2 years, and 6 of those years we (Tripper Lab and I) were here only once a month or so for a weekend..
In June 2018 I acquired Honey Half-lab, now 45 lbs, a spayed female rescue dog, who will be 3 sometime this month. I was doing poop-pickup about once a week or so at first, and was soon seeing dead spots started. I started daily poop patrols and the problem largely went away - especially if I got it within an hour or two (she poops 3 or 4 times a day- hence her Indian name, Poops-a-Lot. My wife calls her Honey Bucket)
And yes- she pees out there at least 6 times a day, and......not a dead spot at this time anywhere! Well except the ones my wife made, but that's another story.
The dead spots from 2018 are all grown in again, a very dark green, as well as others from this year where the poop sat for several hours before being bagged in humid conditions/rainy weather.
At one point late summer 2018, the dog had the runs for a couple days. Even tho I picked it up immediately, it still did a kill job, tho pretty mild. , obviously soaking the grass killing chemical into the ground on contact.
Chako is our nearly 7 month old male Dachsund. I have not noticed his turdlets making kill spots- probably a volume thing, tho it could also be at least partly sex related hormones, I suppose. And boy does he have them- humps everything! Typical Weasel-dog.
From my empirical observations, I consider that female dog urine killing grass theory to be entirely wrong.
I will stipulate that I spread my pee-off-the-deck spots around, having made a dead spot once by not doing so...... too much of a good thing!