The odour of dog urine can be unpleasant for dogs and their owners. When the urine is in an outdoor setting, it can create further problems; other dogs may be compelled to mark their territory when they smell urine, and the high nitrogen content of dog urine can burn your lawn. For dog urine on gravel, there are several things you can do to neutralise the odour and prevent it from causing more problems.
Locate the area where the dog urine is concentrated. Gravel may be stained or wet where a dog has urinated most frequently. Use a black light to find the source of the odour if necessary.
Use a hose to wash the gravel where the dog urine is most concentrated. Thoroughly hose down the gravel to remove and dilute as much of the urine as possible.
Apply a mixture of equal parts water, dish detergent, vinegar and baking soda to the area where the urine is located. Let the mixture sit until it has dried and wash the area with the hose again.
Use an enzymatic cleaner for particularly bad urine odours on gravel. Enzyme cleaners can be sprayed directly onto the gravel or mixed with water before being applied. Enzymatic cleaners will eat away at the urine present and effectively remove the smell of the urine.