Modeling of evaporation reduction in drip irrigation system

Surface drip irrigation is an efficient system for delivering water to crop s; however, conditions at the soil surface affect evaporation rate and effi ciency. A method is proposed, sand tube irrigation (STI), to increase the e fficiency of drip irrigation systems. This method is specific to permanent tree crops where soil is not tilled or turned. The Sn method consists of re moving a soil core beneath the emitter and filling the void with coarse san d. The SWMS-2D model, implemented in a 3D axisymmetric form, was used to si mulate infiltration, water redistribution, evaporation from the soil surfac e, and rise of water inside the sand tube. Model simulations were compared with laboratory measurements determined from a weighing lysimeter. The simu lated values of water height inside the sand tube and temporal position of the wetting front in both lateral and upward directions closely matched the experimental measurements. The advancement of the wetting front in the dow nward direction and evaporation estimates was predicted with less accuracy. Experiments showed that relative to surface drip irrigation, the STI metho d reduced evaporation by approximately 26% over a 4-day period.