A winter hardy, aluminum tolerant, perennial pasture grass for reclamation of acid mine spoils

Abstract Limpograss, Hermarthria altissima, (Poir) Stapf & C. E. Hubb (PI 364344) was tested for Al tolerance in acid, Al‐toxic Tatum subsoil (pH 4.1), in an acid mine spoil (pH 4.0) and in nutrient solutions containing 0 to 24 ppm Al added at initial pH 4.5 or 4.0. The grass was exceptionally tolerant to Al in all three media and can therefore be considered a “calcifuge”;, or perhaps more accurately, an “alumicole”;. In both Tatum soil and mine spoil, liming to pH values above 4.5 decreased growth, but the reasons for this were not determined. In our nutrient culture experiment (initial pH 4.0), the yields of plant tops were not significantly reduced by added Al concentrations up to 6 ppm but roots were injured by 4 ppm Al added. At initial pH 4.5 Al concentrations up to 4 ppm added appeared beneficial to root growth. Both tops and roots produced 50% of maximal yield with a final solution pH of 4.1 and with 17 ppm Al in the solution filtrate. Maximal growth was associated with plant‐induced pH increases ...