Effects of Reclaimed Water Irrigation On Growth and Quality of Turfgrass.

Reclaimed water (RW) is increasingly viewed as a resource for supplying irrigation water and nutrients for landscape plants growth in urban environments. The objective of this research was (1) to determine if the nutrients (specifically N) in RW are available for turf plant nutrition and (2) to compare the effects of reclaimed and potable water on turfgrass growth and quality. The factorial experiment was replicated four times and conducted in a greenhouse on the UF campus using St. Augustine (‘Floratam’) and Zoysia (‘Empire’) turfgrass irrigated with reclaimed water for one year. Treatments included irrigation with tap water (control), full irrigation with reclaimed water, irrigation with reclaimed water amended with and additional 2, 6, and10 mg/L N supplied from ammonium nitrate, and a fertilizer treatment based on the University standardized N recommendation. Major and minor nutrients other than N were standardized across all treatments. Turfgrass visual quality and color ratings were evaluated every 4 wk. Clipping yield, clipping tissue total Kjeldahl nitrogen (TKN), and N uptake were measured 6 times during the experimental period. The nutrient concentration of RW during summer season from the University of Florida wastewater treatment facility on campus varies from 1-3 mg/L for total N and from 0.5 -1.5 mg/L for total P. Turfgrass growth did not differ (P=0.05) between tap water and un-amended RW. Acceptable grass quality resulted when the RW contained N at concentrations greater than 4 mg/L. These results will help guide RW utilities in determining a potential fertilizer off-set for their RW destined for urban landscape irrigation.