Effect of Scrubber Sludge and Fly Ash on Soil Properties and Crop Growth

155 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.Modern coal-fired power plants produce large quantities of scrubber sludge and fly ash that must be disposed of responsibly to avoid environmental degradation. Field and greenhouse studies were conducted to determine the effect of land application of these waste products on soil physical and chemical properties and on corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) growth, nutrient composition, and yield.Scrubber sludge, fly ash, and Poz-O-Tec$\sp\circler$ (a 2:1 mixture of scrubber sludge:fly ash) were each applied to a Wynoose sil (fine, montmorillonitic, mesic Typic Albaqualfs) at rates of 0, 1.12, 11.2, 56, and 112 Mg ha$\sp{-1}$. Scrubber sludge and fly ash treatments were applied in 1984 and Poz-O-Tec in 1985. Corn and soybeans were used as test crops in 1984-1986 and soybeans in 1987.There was a positive corn yield response associated with the low rate of scrubber sludge application in 1984. This result appeared to be an S response. High scrubber sludge rates caused reductions in corn height and grain yield in 1984 and 1986 and in soybean yield in 1987. High fly ash applications produced B toxicity symptoms in corn and soybeans each year, but significant yield reductions occurred only in 1984 for corn and in 1986 for soybeans. High Poz-O-Tec rates did not signficantly affect soybean yield but caused reductions in corn grain yield in 1985 and in corn height in 1986.Scrubber sludge and Poz-O-Tec additions decreased soil cone penetrometer resistance (cone index) at the 5 and 10 cm depths. Cone index was not affected by fly ash additions. Scrubber sludge reduced soil bulk density slightly in the upper 30 cm. Bulk density was unaffected by fly ash or Poz-O-Tec applications. Scrubber sludge and fly ash applications had little effect on soil pH, in part because they were not mixed adequately with the soil. Soil ph was increased by Poz-O-Tec: from 6.8 for control plots to 7.3 for plots receiving 112 Mg ha$\sp{-1}$ of Poz-O-Tec. Boron was slow to move down the profile of this poorly drained soil.In a greenhouse experiment, when mixed well with the soil, both scrubber sludge and fly ash raised soil pH significantly. Low rates of scrubber sludge and fly ash alleviated S deficiency in corn on a sandy soil. At high fly ash rates soil salinity and B reached levels detrimental to plant growth.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD