FREQUENCY OF IRRIGATION FOR SUBSURFACE DRIP-IRRIGATED CORN

Four time-based treatments and four soil water depletion-based treatments were used to evaluate the effect of irrigation frequency on the production of subsurface drip-irrigated corn. Cumulative soil water depletion was calculated and replenished every 1, 3, 5, and 7 days for the time-based treatments. Cumulative soil water depletion was applied to soil water depletion-based treatments when depletion reached 12.7, 25.4, 38.1, and 50.8 mm. No significant differences were found among yields or soil water contents. Significant differences did occur in the irrigation water use efficiency and drainage. The treatments with longer intervals between irrigations had higher irrigation water use efficiencies because rainfall was used more effectively.