The surrounding terrain in your photo's is nothing but foxtail weed. While its green like that its not so bad (still dangerous though) but is deadly when it begins to dry. It dries out and becomes a one way needle with barbs that will penetrate under the the skin and move around in their bodies. I understand you're not going back soon but I strongly urge you not to take him back there this year until that stuff is plowed under and gotten rid of and even then its not completely not safe.( it will be back next year if they do not address this issue.) It takes many years to rid a field of it and you have to use herbicides and till the soil to get rid of it. Personally I think its extremely irresponsible for the owners of the club to let dogs run in that stuff. I put a lot of effort into my training field every year to make sure that we have no foxtail in the areas we train in.