THE GROWTH OF AGROPYRON ELONGATUM IN AN ARTIFICIAL SOIL MIX FROM COALFLY-ASH AND SEWAGE-SLUDGE

A greenhouse experiment was performed to evaluate the feasibility of u sing an artificial soil medium produced from alkaline coal fly ash and sewage sludge for the growth of Agropyron elongatum (tall wheat grass ). Sludge was amended with ash at an application rate of 0, 5, 10, 35 and 50% (w/w). Each mixture was then mixed with a loamy soil at either 1:1 or 1:5 (v/v) and incubated under greenhouse conditions for 3 week s prior to plant growth experiment. Addition of the ash-sludge mixture significantly improved the seedling emergence and dry weight yields o f Agropyron. Pots with 10% ash-sludge mixture at 1:5 v/v soil mixing r atio had the highest yield, while those with 10 and 35% ash-sludge ame ndment at 1:1 v/v soil mixing ratio had lower dry weight yields but we re still higher than that of the control with fertilizer treatment. No deficiency in N and P was noted for the ash-sludge-amended pots at bo th 1:1 and 1:5. Shoot tissue Ca, Mg and B concentrations increased whi le K, Fe, Mn and Zn decreased with an increase in ash amendment rate. The root tissue Fe, Mn, Cu and Zn contents were significantly higher t han those of the shoot tissue. Hence, no excessive accumulation of hea vy metals was noted owing to the ash-sludge amendment. The increased y ield even at a high amendment rate of 35% ash-sludge mixture at 1:1 v/ v soil mixing ratio indicates the potential use of the ash-sludge mixt ure as an artificial soil mix for agricultural use. (C) 1997 Elsevier Science Ltd.