IV. SOURCES AND QUALITY OF THE IRRIGATION WATER - THE EFFECT OF SALINE IRRIGATION WATER ON SOME VEGETABLES UNDER GLASS
During the last years a great number of crops were investigated. The results for lettuce, tomatoes, cucumbers and spinach are discussed. If the electrical conductivity of the irrigation water was increased with 1 mmho/cm (25° C) the yields of lettuce, tomatoes and cucumbers decreased 4, 7 and 14 per cent, respectively. The spinach yields did not show any difference. Sometimes crop quality was affected adversely. In case of lettuce, for instance, addition of sodium chloride to the irrigation water greatly increased the occurence of tipburn.
In the investigation attention was also paid to soil and leaf analysis. It was found that the uptake of several nutrients was influenced by the salt content of the irrigation water