Mineral acquisition by maize grown in acidic soil amended with coal combustion products

Abstract

Large amounts of coal combustion products (CCPs) are produced when coal is burned for generation of electricity. Some of these CCPs could potentially be used as soil amendments, and information about their effects on plant mineral nutrition is needed. Glasshouse experiments were conducted to test the effects of different levels of 15 CCPs and chemical grade CaCO3, CaSO4, and CaSO3 added to acidic soil (Umbric Dystrochrept) on shoot calcium (Ca), sulfur (S), phosphorus (P), potassium (K), magnesium (Mg), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), and aluminum (Al) concentrations of maize (Zea mays L.). The CCPs consisted of two fly ashes (FAs), one CaO material, three fluidized bed combustion products (FBCs), three “non-stabilized” flue gas desulfurization products (FGDs), three “stabilized” FGDs, and three “oxidized” (FGD gypsum) FGDs. Level of CCP added to soil ranged from beneficial to detrimental effects on plants. Differences in shoot mineral element concentrations were related to kind and amount of CCP added and soil pH. Plants grown in unamended (pH 4) soil had symptoms of P and Mg deficiencies and Al toxicity. High concentrations of Ca, S, Mg, and Mn accumulated when plants were grown with some CCPs, but most mineral nutrients were at concentrations considered normal for maize. Shoot concentrations of P, K, Zn, Mn, Fe, and Al decreased when soil pH became high (>7). Even though detrimental mineral element acquisition effects were imposed on plants at high levels of CCP application, shoot element concentrations were usually normal when applied at levels near those commonly used as soil amendments.