Citrus is considered to be specifically sensitive to chloride and sodium, yet little data exist to show the effect of these ions on yield. An experiment was started in 1978 to study the effect of sodic irrigation water on yield. The treatments were SAR of the irrigation water of 2.8-(L), 5.5-(M), and 10.3-(H) (mol/m~) 1/2 (SAR = N a + / [ / C a ++ + Mg++/2). The experiment follows a study on the same plots using irrigation water of variable chloride concentration and a uniform SAR of 4.2 (mol/m~) 1/2.
The high SAR, high C1 water resulted in a yield reduction of 9% from the control treatment. This reduction was similar to the reduction observed when only C1 was a variable. Total water uptake was reduced as salt concentration in the soil increased. The average water uptake for the four irrigation seasons 1978 to 1981 was 1025 mm, 953 m m and 823 m m for the L, M and H treatments, respectively.
Soil ESP was increased as a result of sodium accumulation in the soil profile in the M and H treatments, while C1 and EC remained relatively Constant with time during the experiment. After four years of irrigation the infiltration capacity values were 0.26, 0.17 and 0.16 c m / h for the L, M and H treatments, respectively. Fruit quality was not affected by the treatments.
No specific toxicity symptoms were observed when the Na concentration in the soil saturation extract was 16 m o l / m 5 and the ESP was 8.0. The results lead to the conclusion that within the range used in this experiment the high ESP d i d not specifically effect yield and that yield response was due to the total salt concentration in the soil.