Yield, quality and K/(Ca+Mg) ratio of tall fescue breeding lines on amended and nonamended minesoil

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Abstract
Tall fescue (Festuca arundinancea Schreb) cultivars and breeding lines have been evaluated for yield, nutrient composition and quality on undisturbed lands, but not for these qualities and for adaptability to revegetate drastically disturbed lands. Six breeding lines and 2 cultivars of tall fescue were evaluated for yield, nutrient composition, crude protein and IVDMD [in vitro dry matter digestibility] on limed and unlimed mine soils in west-central Missouri [USA]. The experimental design was a randomized split-block with lime treatment; the split-block, 3-replications, with individual plots 1.21 .times. 3.05 m. Agriculture lime with an ENM index of 291 at a rate of 19 mt/ha was incorporated, fescue seeded and the experimental area mulched during Aug.-Sept., 1978. The 1979 harvest samples were composited for crude protein, nutrient and IVDMD analyses and the 1980 harvest samples were analyzed for individual plots. The 1979 yield was not significantly different between genetic materials, but mean yield from limed mine soil was significantly higher than from unlimed mine soil. Yield data evaluation suggest Kenhy, WG3B, HMR to yield highest on unlimed mine soil and WG2B, LMR and HMR highest on limed mine soil, with Mo-96 lowest in yield, limed or unlimed. The calculated K/(Ca+Mg) ratio of HMR and Kenhy was interpreted to be borderline for potential occurrence of grass tetany under limed environment. Differential divalent cation accumulation capacities of the breeding lines LMR and HMR was expressed on both the limed and unlimed mine soil. K was not judged to reach a sufficiently high or Mg a sufficiently low level to suggest a potential problem of hypomagnesaema. Lime increased IVDMD, but not crude protein. Crude protein varied by year, but IVDMD remained nearly constant. The genetic materials MO-96 and H-I accumulated higher quantities of Mg upon liming, but had lower IVDMD. Differences in yield were not significantly related to cation accumulation or forage quality on this mine soil, limed or unlimed.