Irrigation of Turfgrass with Secondary Municipal Sewage Effluent: Soil and Turf Aspects

Abstract

This field experiment evaluated the use of secondary municipal sewage effluent for irrigation of two turfgrass species. In April 1987 common bermudagrass (Cynodon dactylon L. Pers.) was seeded to a gravelly sandy loans soil and maintained under fairway conditions. Perennial ryegrass (Loliman perenne L.) was overseeded in the fall to maintain an actively growing turf. Plots were irrigated identically with either effluent or potable water. Soil and irrigation water samples were collected periodically and analyzed for pH, electrical conductivity (EC), sodium (Na), calcium + magnesium (Ca +Mg), bicarbonates (HCO₃), nitrogen (N), phosphorus (P) and potassium (K). Effluent water was found to contain a higher sodium absorption ratio (SAR), EC and greater concentrations of all the above elements with the exception of pH. Effluent irrigation lead to significantly lower seed germination and resulted in higher EC, Na, nitrate- nitrogen (NO₃-N), P and K concentrations in soils. Turf quality was assessed by visual evaluation under four N fertilization rates in each irrigation regime. Established effluent irrigated turf did not show signs of osmotic stress with a 15-20% leaching fraction and responded to the nutrient content of this water during periods of higher irrigation rates. However, no single fertilization rate or irrigation regime consistently produced a superior turf quality. Secondary municipal sewage effluent was used successfully for turf irrigation but the greater EC, Na and nutrient content of the water need to be considered by the turf professional making management decisions.