A Preliminary Study on the Potential for Cycling Solids from Geotube Treatment of Dairy Lagoon Wastewater

Abstract: Geotube® residual solids (GRS) are a potential bioresource that could be used to improve soilphysical and chemical properties on agricultural land. Yet, chemical pro perties of GRS could affect plant growthand repeated land application of GRS could elevate soil nutrient content and contribute transport and loss ofnutrients in drainage water. The first objective was to evaluate the effects of increasing rates of GRS n ophysical, chemical and biological properties of contrasting soil types during turfgrass establishment.The second objective was to evaluate leaching losses of nutrients from contrasting soil types with and withoutincorporation of GRS during turfgrass establishment. Incorporation of GRS enhanced turfgrass growth andphysical and chemical properties of contrasting soil types. However, following application of GRS, soilconcentration of NO 3-N exceeded turfgrass uptake and excessive leaching loss of NO 3-N occurred. At high soil pH, residual Alum and associated hydrolysis products in GRS did not increase extractable soil Al, but didminimize leachate concentrations of dissolved reactive P forms. Composition, timing and application rate ofGRS should be managed to optimize turfgrass establishment and prevent leaching loss of dissolved nutrients.