Surface Sealing Effects on Infiltration with Surface Irrigation

Abstract

A numerical model was used to simulate one-dimensional infiltration of overland flow into surface sealed soils. Three soil textures were studied. The hydraulic conductance of the surface seals as a function of time and the hydraulic properties of subseal materials were obtained from laboratory data. Infiltration was not always significantly influenced by surface sealing. Sealing had the most control on infiltration when the seal was already present at the beginning of the irrigation. With a silty clay loam soil, reductions in cumulative infiltration were as high as 20 and 49% when the media below the seal was layered and uniform, respectively. The relative effect of sealing on infiltration was sensitive to the mathematical form and hydraulic parameters of the hydraulic conductivity function of the material beneath the seal. Subsidence of the tilled zone between water applications, to a pre-tillage density and hydraulic conductivity, significantly affected infiltration.