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The response of 4 temperate grass species (Lolium perenne cv. Victorian, Thinopyrum ponticum cv. Tyrell, Austrodanthonia richardsonii cv. Taranna, A. bipartita cv. Bunderra) to saline irrigated conditions was evaluated over 4 seasons at Tatura in northern Victoria. This experiment followed earlier research where the salt tolerance of ~20 species of grasses was evaluated in the greenhouse. Field plots were established under non-saline conditions and were irrigated with saline water at 1.6, 2.5, and 4.5�dS/m. Measurements made on these plots included dry-matter production, tissue ion (Na+, Cl?, K+, Mg2+, Ca2+) concentrations, in vitro dry-matter digestibility, root distribution, and soil chemistry. Soil salinity (EC1�:�5) and sodicity (SAR1�:�5) levels peaked at 0.30?0.60�m depth and reached 1.3�dS/m and 9.8, respectively, for the highest saline irrigation treatment. Cumulative plant dry-matter production was lower in T. ponticum compared with the Austrodanthonia species and L. perenne at all salinity levels, but in relative terms there was no difference in the salt tolerance among any of the 4 species (the reduction in dry weight at 4.5�dS/m was 10?15% for all species). Leaf tissue concentrations of Na+ and Cl? were significantly lower in A. richardsonii and A. bipartita compared with T. ponticum and L. perenne, and in vitro dry-matter digestibility tended to be greater in L. perenne under saline conditions than in the other 3 species. This research suggests that the 2 native Austrodanthonia species can be grown under moderately saline conditions?either under saline irrigation or in a dryland discharge area?in environments where perennial ryegrass may also be grown. |
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