There are things in the dirt/mud that can be unhealthy for them. The main I can think of would be bacteria and worm eggs.
I have never personally experienced this with my dog, but did see it corrected it in a dog by putting them on Pet Tabs for 2 months or one 60 ct bottle. For this dog it was anemic and was looking for an iron boost. Depending on where you live the mineral levels in the ground are higher and of course "taste good" to them. But, it then upsets the stomach and they throw up.
She may be thirsty, be sure to take some water to the park.
Or she could be just having a good time.....In that case it is a behavior issue and I think Liz may can give you better advice on that one for correcting the issue.
I have never personally experienced this with my dog, but did see it corrected it in a dog by putting them on Pet Tabs for 2 months or one 60 ct bottle. For this dog it was anemic and was looking for an iron boost. Depending on where you live the mineral levels in the ground are higher and of course "taste good" to them. But, it then upsets the stomach and they throw up.
She may be thirsty, be sure to take some water to the park.
Or she could be just having a good time.....In that case it is a behavior issue and I think Liz may can give you better advice on that one for correcting the issue.