Is the Partial Root Drying Irrigation Method Suitable for Sandy Soils? Field Experiment and Modelling Using the Saltmed Model

Abstract

AbstractThis study investigated the impact of regulated deficit irrigation (RDI) and partial root drying (PRD) on soil moisture, dry matter, and yield and water productivity of maize grown in sandy soil in Egypt. The experiment was conducted in 2013 and included eight treatments of RDI and PRD. Four RDI treatments [100% full irrigation requirement, FI (control), 80% FI, 60% FI and 40% FI] and four PRD treatments [100% PRD, 80% PRD, 60% PRD and 40% PRD] were conducted. The experimental and simulated results using the SALTMED model showed that maize yields obtained under RDI were higher than those obtained under PRD; this may be due to the fact that the soil is sandy and the PRD treatment received relatively less irrigation water. The latter perhaps have led to a smaller and narrower wetted soil volume within the root zone, and possibly some of the water was partly lost below the root zone due to the high infiltration rate commonly associated with sandy soils. The correlation between the observed and simulated grain yield showed that the SALTMED model was able to simulate grain yield and water productivity for all treatments with high accuracy, producing an average R2 of 0.98 and 0.95, respectively. © 2018 John Wiley & Sons, Ltd.