Different Concentration Levels Of Graywater Applied To Landscape Plants Does Alter Soil Nutrient Levels and Plant Growth.

Different concentration levels of graywater applied to landscape plants does alter soil nutrient levels and plant growth

The supply of potable water is becoming a rare resource.  Graywater is an alternative water reuse source collected from sink basins, clothes washing machines, and showers could be used on household landscape plants to decrease the overall potable water use.  The objectives were to determine 1) the impact of synthetic graywater on both bare soil as well as flowers found in a residential landscape, 2) the changes in soil chemical properties of landscape soils receiving graywater, and 3) relative growth and fitness of geranium maverick quicksilver (Pelagonium x hortorum ‘Maverick Quicksilver’), irrigated with graywater. This study used synthetic graywater to irrigate flowers and bare soil in 46 cm tall columns that were 15 cm in diameter, at the Fabian Garcia Research Center greenhouses in Las Cruces, New Mexico. The flowers and bare soil columns were organized separately in a completely randomized design with three replicates. Biweekly relative growth rates of the flowers were taken as well as regular testing of the pH and electrical conductivity of the column leachate.  Soil tests were conducted at four different depths to determine nutrient load as well as the accumulation of salinity upon completion of this short-term experiment. The initial findings for leachate showed no significant increase in salinity and no significant change in pH.  Results showed that plant growth was negatively impacted at the higher concentration levels of synthetic graywater throughout the study.  Lower concentration levels of graywater showed no detrimental effects on plant health. Graywater appears to be a viable conservation strategy to decrease the potable water use while allowing homeowners to maintain aesthetically pleasing landscapes.