Phosphorus run-off from urban lawn care is a significant water quality concern in many US suburban communities. Many state and municipal governments in the USA adopt urban fertilizer laws or ordinances that prohibit the use of phosphorus-containing lawn fertilizers. This study assesses the long-term water-quality impacts of two phosphorus-reduction scenarios in a suburban watershed in Central New Jersey. While Scenario I reduces the phosphorus fertilizer application rates by 25%, Scenario II completely eliminates phosphorus fertilizer for urban lawns as required by such laws, rules or ordinances. The long-term water-quality impacts were estimated using the Soil and Water Assessment Tool and then compared to the total maximum daily load (TMDL) water-quality standards using the load duration curve approach. Scenario I will decrease total phosphorus (TP) load to streams by 15.34%. Scenario II achieves greater reduction in TP load to streams than Scenario I, but results in excessive nitrogen run-off and violation of the TMDL standard for total nitrogen. While many regulatory measures focus on reducing phosphorus run-off by prohibiting the use of phosphorus in urban lawn fertilizer, they should be carefully implemented to balance the nutrient needs to maintain healthy lawns and avoid such unintended consequences.
Assessing long-term water quality impacts of reducing phosphorus fertilizer in a US suburban watershed
Zeyuan Qiu, Tony Prato, Hongmei Wang; Assessing long-term water quality impacts of reducing phosphorus fertilizer in a US suburban watershed. Water Policy 1 October 2014; 16 (5): 917–929. doi: https://doi.org/10.2166/wp.2014.163
Download citation file: