Irrigation Water Chemistry: Impact on Microbial Community Composition and Biogeochemical Leaching under Perennial Ryegrass (Lolium perenne [L])

Greywater recycling and rain water harvesting for irrigating urbanand suburban landscapes may reduce the use of potable water inarid and subtropical climates but affect soil microbial communitycomposition and biogeochemical cycling. Municipal tap water,greywater, and harvested rain water were used to irrigate( Lolium perenne L.) planted in a constructed soilover a 20 week period. Irrigation with grey water significantlyincreased the relative abundance of gram-positive biomarkersANTEISO 15 : 0, ISO 17 : 1G,gram-negative biomarkers 19 : 0 CYCLO c11-12 and bacterialbiomarker 18 : 0 () relative to irrigation withharvested rain water. Significant decreases were observed in therelative abundance of gram-positive biomarker16 : 0, gram-negative biomarker16 : 1 ω 7c, both fungi biomarkers(18 : 2 ω 6c and 18 : 1 ω 9c) in soils irrigated with greywater (). Dissolved organic carbon losses from soil were a significanttwo-to-four times greater from soils irrigated with municipal tapwater and greywater relative to soils irrigated with harvestedrain water(). This study highlights the effect thatmunicipal tap water and grey water may have on microbial communitycomposition and soil nutrient dynamics under irrigated turf grass.