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The effect of salinity on the growth and survival of different local and imported strains of Rhizobium meliloti in liquid media for 72 h was studied in the laboratory. The rhi‐zobial strains were tested for their symbiotic efficiencies with lucerne grown in salinized sand culture and in natural Saudi Arabian soils of different salinities in the greenhouse. Results have shown that growth of all rhizobial strains investigated in liquid media was adversely affected by high salinity with relatively slight salt tolerance in the local rhizobial strains. Salinization of sand culture to high concentration (100–250 mM NaCl) greatly affected nodulation and symbiotic N2‐fixation of lucerne plants grown in it. Growing lucerne in sand of high salt concentration (250 mMNaCl) completely prevented the formation of nodules. Inoculation of lucerne plants grown in sand culture with local isolates of R. meliloti has shown slight salt tolerance up to 100 mM NaCl. These local isolates gave relatively higher symbiotic N2 ‐fixat...

On an initially non-saline calcareous soil, the advanced wheat line RI 3748 (Triticum aestivum L.) was irrigated by sea water dilutions having ECi-2, 12, 18 and 24 mS cm−1 at 20°C in quantities equal to 1.1, 1.3, and 1.5 times evapotranspiration. Leaching of the soil (L) significantly affected concentrations of N, Ca, P, Na, Cl, and Mg in topgrowth at specific ages. These effects were attributed to the non-steady state salinity of the rootzone and were found to be of minor importance with respect to plant performance. Concentrations of Ca and N did not respond to ECi. Nitrogen and P levels were very low under all ECi levels and decreased rapidly until maturity. Sodium and Cl attained fairly high concentrations in plant tops, in response to ECi and plant age. However, it was found that up to ECi=12 increased absorption of Cl controlled its concentration whereas above this level, growth inhibition was the cause of higher Cl concentrations.

Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S1=3.5, S2=6, S3=8.5, and S4=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W1), 40% (W2) and 20% (W3) of the available water.

Sea water dilutions having ECi=2, 12, 18 and 24 mmhos/cm, at 20°C were used for weekly irrigations of the wheat line RI 3748 (Triticum aestivum L.) on an initially non-saline calcareous loamy sand soil. The added quantities were 1.1, 1.3 and 1.5 times the weekly evapotranspiration. The vegetative growth (G), grain yield (Y), g/1000 grains and ECe were significantly affected by ECi and not by L. ECiXL affected g/1000 grains and the early G only.