Effect of Dried Anaerobically Digested Sewage Sludge on Yield and Element Accumulation in Tall Fescue and Alfalfa1
- Donald J. Stucky and
- Tommie S. Newman2
Two rates of dried anaerobically digested sewage sludge were used in a greenhouse pot study to determine the effect on yield, areal coverage, and element accumulation in ‘Ky-31’ tall fescue (Festuca arundinacea Schreb.) and alfalfa (Medicago sativa L.) grown during a 2-year growth period, on an agricultural soil and on acid strip-mine spoil. The initial pH of strip-mine spoil was approximately 3.5, and sludge additions of 314 and 627 metric tons/ha raised the pH to 5.5 and 6.0, respectively.
Sludge applications of 314 and 627 metric tons/ha significantly increased yields of plants grown on agricultural soil. On strip-mine spoil, yields of tall fescue and alfalfa were significantly increased at the application rate of 627 metric tons/ha. In all treatments the yields of alfalfa were greater than that of tall fescue, although the areal coverage of fescuexceeded that of alfalfa.
Increasing rates of sewage sludge decreased the amount of Mn, Zn, Ni, and Cd accumulated in tall fescue and alfalfa in strip-mine spoils. Copper accumulation was not affected by application rates. In tall fescue, per day accumulations of Mn, Zn, Cu, Ni, and Cd followed similar patterns, peaking between the 180- and 200-day growth period. This trend was observed in alfalfa for Mn and Cd; however, Zn, Cu, and Ni accumulations decreased with time. The percent areal stem coverage after 2 years was estimated at 95 and 65% for tall fescue and alfalfa, respectively. No plant toxicity symptoms were observeduring the 2-year growth period.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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