EnviroHorse 3027 St. James Rd. Abstract Ammonia and nitrogen in horse urine rapidly volatilizes into the atmosphere or adsorbs to soil when deposited on the ground. Horses have unique behavior involving urination.
Most horses urinate in their paddocks or pastures.
Simple management practices can avoid urine deposition in water bodies by trail horses. Unless there is direct deposition in water, the risk of horse urine excreted on trails providing nutrient enrichment to weeds on trails or contaminating streams will be extremely small. This is a companion piece to Horse Manure Aging and Nutrient Content and Implications for Trails by EnviroHorse, and many of the same references apply. Background Some have speculated that horse urine on trails can provide nutrient enrichment for weed seeds. The presence of ammonia in water bodies, even in very small amounts, has been shown to be harmful to some aquatic life, particularly salmonids.