Soil Water Flow Patterns due to Distance of Two Emitters of Surface Drip Irrigation for Horticultural Crops

Surface drip irrigation is one of the most efficient systems for irrigating vegetables. The patterns of soil water distribution formed under the emitter are important for designing an optimal drip irrigation system. This study aims to evaluate the soil water patterns between two emitters using field experiments and numerical simulations. Field experiments were conducted using two emitters with different lateral spacings (20, 40, and 60 cm). Frequency domain reflectometry (FDR) sensors were used to measure the soil water content. HYDRUS-2D software was used to simulate water infiltration in the field experiments. At a short lateral spacing (20 cm), the water content started to increase at 30 min and saturated at 200 min. These values became significantly larger as the lateral spacing increased-300 min and saturated at 700 min at 40 cm and 900 min and longer than 22 hours at 60 cm, respectively. The simulated water contents were in satisfactory agreement with the experimental values (R-2 = 0.97, RMSE = 0.009 cm(3) cm(3), E (coefficient of efficiency) = 0.959). These results provide valuable information that can be used to design an efficient surface drip irrigation system for vegetables, thereby improving crop productivity and quality.