The climatic conditions of Iran requires that in order to optimize the use of water and to increase the irrigation efficiency, sprinkle irrigation systems should be used. On the other hand, water scarcity encourages the use of this type of irrigation systems which conserve irrigation water. Unfortunately water scarcity is often accompanied by poor water quality, Under this conditions, sprinkle Irrigation has deterimental effects due to leaf burn and defoliation. In order to quantify yield reduction under this type of water, an experiment was set up on the Agricultural Research Station, Varamin, Tehran, in a completely Randomized Block design. Irrigation water was applied through sprinkler and furrow systems with four levels of salinity(0.36, 2.13, 3.97 and 7.8 dS/m) with four replictions to evaluate the extent of leaf injury, foliar absorption of Cl and Na ions and yield response. The evaluation of the chemical analysis of leaves on the sprinkled plots indicated that the rate of ion absorption was increased during the growing season but on the furrow- irrigated plots, the rate of absorption was not signficant for both the sprinkled, and furrow irrigated plots.The yield reduction of cotton on the treatment levels of 3.97 and 7.8 dS/m on the sprinkle-irrigated plots were about 25 and 36 percent, respectively, compared with treatment level of 0.63 dS!m but, statistically speaking, there were no significant differences between the treatment levels of 1 and 2.The yield reduction of cotton on the treatment level of 7.8 dS/m compared with treatment level of 0.63 dS/m on the furrow - irrigated plots was about 19 percent.
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