PLANT AND SOIL COMPOSITION AS AFFECTED BY AN ALTERNATIVE LIME SOURCE CONTAINING SULFATE

The reduced crude oil conversion system uses a fluidized bed combustion system for in situ SO, removal. The reduced crude conversion spent lime (RCCSL) that results contains mostly CaO, CaSO4, and MgO. This material was evaluated as an alternative lime source in greenhouse studies with tobacco (Nicotiana tabacum L.) and corn (Zea mays L.). Equivalent amounts (CaCO3 basis) of RCCSL, reagent grade Ca(OH)2, and agricultural-grade (ag) dolomitic limestone were applied at rates of 0, 0.33, 0.67, 1.0, and 1.33 times the 50 mmol CaCO3 kg-1 soil lime requirement (LR) to an acid Maury sill loam (fine, mixed, mesic Typic Paleudalf). The RCCSL and Ca(OH), were equivalent in raising the soil pH and reducing active Al3+, H+, and Mn2+. Ag lime was less effective. Soil solution electrical conductance increased with increasing rate for Ca(OH)2 and RCCSL, but not for ag lime. After 5 wk, plant dry matter was highest at 0.33 and 0.67 LR. Dry matter was reduced for both crops by the highest application rate of all lime sources. Leaf tissue N, K, S, B, and Zn generally declined with increasing lime rates. Chloride accumulation increased with rate and was higher with RCCSL. No deleterious or unusually high amounts of Cd, Pb, Ni, or V were detected. The overliming response could not be ascribed to impaired P, Mg, or Zn nutrition in either species and was speculatively attributed to Al toxicity at near-neutral pH. The results indicate that field evaluations of the RCCSL material are warranted.