I have a large dog and when I let her into the yard to "do her business", How come there are brown spots here or there in the lawn after the dog eliminates in that spot....and how do I get rid of those spots to make the grass green again, (of course without using chemicals that can harm my dog)?

try letting your dog eat some fertilizer... lol just kidding. i love dogs!

You can't.....best thing is to train your dog to go in one certain spot or take it for a walk and let it go somewhere else.