Effect of Scheduling Irrigation Based on Pan Evaporation to Wheat on Sodic Soils

Optimum schedule of irrigation for wheat and its response to irrigation based on ratio of irrigation water and cumulative pan evaporation (IW/CPE) was studied in a field experiment during 1986–87 and 1987–88 on a sodic soil (pH 9.2; ESP 38). An increase in IW/CPE ratio resulted in greater relative growth rate, yield attributes and yield of wheat. The seasonal ET of crop with 1.0 IW/CPE ratio was 332.4 and 338.5 mm, of which 75.7 and 69.0 mm was extracted from 0 - 0.90 m soil profile during 1986–87 and 1987–88, respectively. Most of the seasonal ET of crop took place from 0–0.15 m soil layer and increased from lower layers with an increase in IW/CPE ratio. However, the total amount of seasonal ET from all the layers was greater under higher IW/CPE rate. Maximum water use efficiency of 6.49 and 6.55 kg grain⁻¹ mm⁻¹ of ET was recorded when irrigation was given at 1.0 IW/CPE ratio than at the other treatments.