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Differential Tolerance of Weeping Lovegrass Genotypes to Acid Coal Mine Spoils

Foy, C. D., Voigt, P. W., Schwartz, J. W.
Agronomy journal 1980 v.72 no.6 pp. 859-862
Eragrostis curvula, chlorosis, calcareous soils, acid soils, genotype
Plant genotypes having greater tolerance to mineral stress are needed for use on problem soils. Two examples of such stress are mineral element toxicity (excess Al, Mn, etc.) in strongly acid soils and mine spoils, and Fe-related chlorosis in certain calcareous soils. Previous studies showed that genotypes of weeping lovegrass (Eragrostis curvula (Schrad.) (Nees) and Lehmann lovegrass (Eragrostis Lehmanniana Nees) different widely in their susceptibilities to an Fe-related chlorosis on calcareous soils. Preliminary observations suggested that certain genotypea also differed in tolerance to acid mine spoils. To test this hypothesis more precisely, 16 genotypes of weeping lovegrass were grown in greenhouse pots of a Pound, Va., coal mine spoil adjusted to pH 3.5 and 4.7 with CaCO₃, and in a Beckley, W.Va., spoil having a natural pH of 4.3. Weeping lovegrass genotypes differed significantly in tolerance to the strongly acid mine spoils. For example, in one experiment the relative top yields (pH 3.5/pH 4.7%) varied from 20.8 to 0%. In certain genotypes, tolerance to acid mine spoil coincided with susceptibility to chlorosis on calcareous soils. For example, Morpa, Beltsville Native, NPMC Hill Culture, and common genotypes were among the most tolerant to the acid mine spoil at pH 3.5, but these were among the most susceptible to chlorosis on calcareous soil at pH 7.8. Conversely, the genotypes FQ 22, FQ 150, FQ 7, and FQ 14 died on the spoil at pH 3.5, but were among the most resistant to chlorosis on calcareous soil. No genotype tested was well adapted to both acid mine spoil at pH 3.5 and calcareous soil at pH 7.8. However, most genotypes studied made reasonable growth on mine spoils of pH 4.3 and 4.7. Results indicated that two commercially available cultivars, Morpa and common, were among the most tolerant tested on mine spoil at pH 3.5; hence, additional genetic diversity will be required to improve acid soil tolerance. Plant toxicities produced in the acid mine spoils studied were tentatively attributed to interference by Al and Fe in the uptake and use of Ca and P.