Off-leash dog parks are very popular locations that allow pets to freely exercise and eliminate wastes in a controlled environment. Although dog park rules require that solid waste be removed by the pet’s owner, urine-borne constituents in dog-park soils have received little attention. This study focused on the soils within two small-dog, off-leash dog parks in Fargo, North Dakota (USA) with the objective to better understand the concentration and distribution of extractable NH4-N, NO3-N, PO4, soluble salts, and pH values in surface soils (0–10 cm) within these two dog parks. Concentrations of soil variables varied widely within each park and were distributed as both gradient and ‘hot-spots.’ The geospatial model types for each soil parameter were more dependent on park than on the constituents themselves. Flow accumulation was correlated with both nitrate-N and P but due to the lack of topography at these parks the flow accumulation was not helpful in describing most of the soil constituents. The results from this project indicate that location of parks, daily/annual use of parks, flow accumulation, and location of park entries may all influence the concentration and distribution of urine-borne constituents.I added my own emphasis there at the end to highlight the studies conclusions. I'd also like to share one more dramatic fact from the article:
In the United States, dogs produce over 53 million L of urine daily (Beaver 1999). Correlating this value to the population of dogs in the US, each dog produces about 736 mL of urine per day. The concentration of nutrients excreted with dog urine is diet dependent, and in Beagles the total N ranges from 5,000–40,000 mg/L (Castrillo et al. 2001) and an approximate P content of 2,210 mg/L (Wood et al. 2004).America's dogs, why are you peeing so much?