Steel Industry Slags Compared with Calcium Carbonate in Neutralizing Acid Mine Soil (1)‪.‬

ABSTRACT. Ohio has substantial lands impacted by surface mining for coal and an active steel industry. Steel industry slags have been used as liming compounds for agriculture and acid mine soil reclamation. This 3-year study evaluates slags from Ohio steel mills in greenhouse trials where these materials are compared to reagent grade CaC[O.sub.3] in their ability to improve plant growth on acid mine soil. The objectives of this study were to evaluate the effectiveness of these materials at two rates of application in raising acid mine soil pH and to address concerns about metals in such slags. Three slags and reagent grade CaC[O.sub.3] were applied at rates equivalent to 12.5 and 25 g CaC[O.sub.3] [kg.sup.-1] soil on acid mine soil (pH = 3.5). Five consecutive crops of oats (Avena sativa L.), wheat (Triticum aestivum L.), corn (Zea mays L.), wheat and soybean (Glycine max (L.) Merr.) were grown and harvested at the seedling stage. The slags and CaC[O.sub.3] increased yields (P 0.01 level) compared to unlimed control pots. Soil and plant Ca were increased and plant Al and Mn decreased by application of all four materials. The slags increased soil and plant Mg. Particle size of the slags was somewhat coarse which decreased their effectiveness, but overall these slags proved to be satisfactory liming materials. The fineness efficiency developed for carbonate forms of lime may not adequately characterize slag effectiveness. Micronutrient metals including iron were not found to be in excess in plant tissue treated with slags despite the steel slags' high Fe content. INTRODUCTION