Is My Landlord Harassing Me?

I have received several e-mails from my landlord regarding my dog urinating and defacating on the lawn in my backyard. I agreed to pick up the droppings and to pour water on his urine immed. Which I am complying with. He continues to deny that I am doing what we agreed upon in our attachment to the rental agreement. He will not accept that I am already very conscientious about doing this.He states that he had dog feces on the tires of the push mower as evidence. The yard is not fenced/ other dogs use it.