Ok I’ll bite:

30 horses in the park, 6h per horse per day, uniform pooping

Call it 14 kg of feces per day per horse

Humans shit ~100g/day

115k park visitors a day

For humans to match that horse output, nearly 1% of all daily visitors would have to be pooping on the ground…

Granted, the horses have waste catchers, but even under a 90% efficiency regime it’s still 10kg of horseshit spread over the lower loop