RESPONSE OF WHEAT TO SALINE IRRIGATION AND DRAINAGE

The response of wheat (Triticum aestivum L.) to varying depths of irri gation, quantity of water applied and to the drainage conditions was s tudied in 2 m x 2 m x 2 m size lysimeters filled in with a sandy loam soil. Saline water with an electrical conductivity of 8.6 dS m(-1) was used for irrigation. The treatments included four irrigations of 5 cm depth. four irrigations of 7 cm, and three irrigations of 9 cm, sched uled on the basis of cumulative pan evaporation, while the drainage co nditions were represented by the drained and undrained lysimeters. Ano ther treatment, using good quality water for irrigation, represented t he potential yield of the crop. The growth parameters, as well as the yield, showed an improvement with larger irrigation depth increments i n the drained lysimeters. But, in contrast, in the undrained lysimeter s, the yield was reduced with larger irrigation depth increments, main ly due to a sharp rise in water table depth during the irrigation cycl es. The rise and fall in water table showed a high sensitivity and wer e also highly disproportionate to the irrigation and evapotranspiratio n events. The yield tended to be higher with a smaller depth of water applied more frequently in the undrained lysimeters. But, in view of t he limitations of conventional surface irrigation to apply water in sm aller depth increments, an improved drainage is imperative for croppin g in shallow saline water table conditions. (C) 1997 Elsevier Science B.V.