Response Water Productivity and Sorghum Yield to Deficit Irrigation Under Surface Drip Irrigation System

Abstract

A field experiment was conducted during the spring season of 2022 in a clay loam soil at the experimental station of the College of Agricultural Engineering Sciences, University of Baghdad - Al-Jadriya, in order to study the effect of deficit irrigation on the growth and productivity of Sorghum, using the surface drip irrigation system, the experiment included irrigation treatments with six levels of full irrigation treatment FI100 When 50% of the available water is depleted, it is compensated by the American evaporation basin class A, from which the deficit irrigation treatments 80, 70, 60, 50, and 40% of the complete irrigation were applied, using the RCBD with three replications. The treatments were applied during the included plant growth stages (vegetative growth, flowering and maturity). Crop growth indicators were measured at the end of the season. Sorghum seeds were sown on 3-13-2022 and harvested on 7-15-2022. The results showed that the seasonal water consumption of corn reached its highest value when the full irrigation treatment was 487.24 mm when 50% of the available water was depleted, then it decreased to 413.59, 376.94, 340.29, 303.63, and 266.98 mm for the deficit irrigation treatments (80, 70, 60, 50, and 40%) calculated from the control treatment (FI%100). Irrigation treatment (FI 100%) gave the highest values for average plant height, leaf area, chlorophyll content, total root dry weight and yield. Water consumption amounted to 413.59 and 376.94 mm compared to the full irrigation treatment, while the treatments (60, 50 and 40) % of the full irrigation were superior in that they saved an amount of water at the expense of low crop productivity. The highest water productivity was recorded at two irrigation treatments minus 80 and 70% for the Sorghum bicolorcrop. It amounted to 13.71 and 15.13 kg m3, as the lack of 20 and 30% of the irrigation water did not affect the productivity. It is recommended to irrigate at a rate of 80 and 70% of the total ETa, which indicates the possibility of providing 20 and 30% of the full irrigation needs without affecting the grain yield.