Incinerated sewage sludge use as a soil amendment for sweet corn (Zea mays L.)

Graduation date: 1980Field and greenhouse experiments were conducted to determine the suitability of using incinerated sewage sludge ash as a soil amendment for sweet corn production on Willamette silt loam. In 1977, field plots were treated with 0, 11, 22, and 43 mt/ha of ash containing lime, in factorial combination with a P fertilizer variable (0 or 90 kg/ha P). In 1978, additional ash containing alum was applied to P fertilized plots only, resulting in cumulative ash rates of 27, 53, and 106 mt/ha. Sweet corn was grown both years and NH₄NO₃ and NH₄ SO₄ fertilizer was applied to provide N. Ash samples contained between 9 and 18% P₂0₅ and from 2 to 34% CaCO₃ equivalence. Elements assayed for in the waste and found in excess of 1% included Ca, P, Fe, and Al. Metals found in concentrations ranging from 0.1 to 1% were Mg, K, Na, Zn, Pb, Mn, Cu, and Cr; while Ni, B, Cd, and Mo concentrations were less than 300 µg/g. Soil pH increased from 5.3 to 6.0 with the highest ash application. Exchangeable Ca and available P; total P, Zn, Cd, Cu, Ni, Pb, and Cr; and DTPA-extractable Zn, Cd, Cu, and Pb content of the surface soil (0-15 cm) increased with ash applications. DTPA-extractable Mn decreased with waste addition while extractable Ni and Cr, and exchangeable Mg, K, and Na were not measurably affected. Water extracted a small portion (