Influence of fly ash and soilless substrates on chemical properties of their compound medium and tall fescue growth

Fly ash is a by-product from coal combustion in electrical power plant. Beneficial use of this by-product is of great economic and environmental impact. The purpose of this study was to explore the influence of fly ash and other three soilless substrates on chemical properties of their compound medium and to develop soilless substrates for sod production. Fly ash, peat, sawdust, and rice husk was mixed in different proportions to form 10 mixtures in a simplex-lattice design, and a native soil was used as control. Tall fescue (Festuca arundinacea Schreb.) was grown to evaluate the growth media. The results showed that fly ash increased EC, pH and concentration of extractable phosphorus in the mixtures. Peat mixtures had higher contents of Fe, Mg, and Na. Rice husk increased extractable potassium in the mixtures. Peat and fly ash in 40/60 (v/v) had the best tall fescue coverage. Judged by chlorophyll content and quantum yield, no negative influence was found on the tall fescue by the soil amendments till fly ash was more than 60% (v/v). A regression model was developed to predict the dates to full coverage as affected by different components.