Success StoryPhosphorus in Fido's Feces



Phosphorus in Fido's Feces

Author: Brad Lee

Planning Unit: Plant and Soil Sciences

Major Program: Urban Environments (water issues)

Outcome: Initial Outcome

As dogs become more popular and human populations concentrate in urbanized areas, management of canine excrement will become more important. Nutrient contribution quantity to stormwater attributable to canine sources are not known to the regulated Municipal Separate Storm Sewer System communities (MS4s).  Quantification of nutrients from canines is particularly important to states like Kentucky, which ranks 3rd in the nation in canines per household.  Individually packaged excrement samples were collected from 1005 canines in Kentucky urbanized areas and characterized for nutrients. Mean mass per feces sample collected was 83.13 g (s.d. 57.93 g, range: 4.17 g - 438.29 g, n = 746). Moisture content averaged 69.2% (s.d. = 5.5%, range: 31.3% - 91.1%, n = 746), nitrogen (N) averaged 3.9% (s.d. = 0.8%, range: 0.9% - 6.5%, n = 1005) and phosphorus (P) content averaged 3.14% (s.d. = 1.0%, range: 0.4% - 8.0%, n = 1005). The Environmental Protection Agency estimates that the average dog produces 125 kg of feces annually. Using this value, the canine population of Kentucky adds 2245 Mg N and 1729 Mg P to the environment each year. At the household lawn scale, the average canine adds 1.2 kg of P and 1.5 kg of N. Using the University of Kentucky recommended annual application rate of 0.9 kg N per 93 m2 lawn, one average dog would apply enough N to cover a 155 m2 lawn and 2-fold the amount of P applied at the N-equivalent rate of a 10-10-10 (N-P-K (potassium)) fertilizer. These results suggest that dog excrement is a significant source of nutrients in the urban environment and should be taken into consideration when developing MS4 nutrient management strategies.