Abstract
Sugar-cane cultivars N.Co.310 and H50-7209 were grown for eight months in the glasshouse with five months of saline water irrigation. A low humic latosol which is structurally resistant to salinity and sodium hazards was chosen as the growth medium. Solutions of NaCl, Na2S04 and sea-water were used for irrigation at concentrations equivalent to electrical conductances of 2 (low), 4 (medium), 6 (medium high), and 8 (high) mmho/cm. Controls were irrigated with tap-water. Salt accumulation from applied waters was minimized by allowing appropriate water excesses to leach through the soil at each irrigation. Increasing salinity in irrigation water caused decreases in fresh and dry matter yields. At low salinity the loss in dry yield was ten per cent. The loss increased to 35 per cent at high salinity. Effects of salinity appeared to be greater on N.Co.310 than on H50- 7209, especially at the lower salinity levels. Salinity effects on stalk elongation agreed with published data on effects of moisture stress, suggesting that the osmotic component of salinity is more dominant in reducing cane yield than are specific ion effects.
