Wetting front advance patterns and water losses by deep percolation under the root zone as influenced by pulsed drip irrigation

The increased use of trickle irrigation is seen as a way to improve the sustainability of irrigation systems around the world. However, soil hydraulic properties, trickle discharge rate and irrigation frequency are often not adequately incorporated in the design and management of trickle irrigation systems. The influence of the before-mentioned factors on the wetting front advance and on the water losses by deep percolation under the root zone was studied for surface trickle irrigation. For this purpose a cylindrical flow model incorporating evaporation from the soil surface and water extraction by roots was used. The results show that, for both types of soils used in this study and for the two discharge rates, the vertical component of the wetting front was greater for the pulse than for the continuous irrigation for a time equal to irrigation duration. However, this difference was practically eliminated for a longer time.