Effect of Soil Surface Conditions on Infiltration for Shallow Water Table Soils

Abstract

ABSTRACT EXPERIMENTS were conducted to determine the effects of surface cover and changes in surface conditions on infiltration into soils with shallow water tables. The effects of initial water table depth and time of year were also considered. Experiments were conducted on columns of fine sand with bare or fallow surfaces as well as surfaces planted to fescue grass and soybeans. Highest infiltration was observed for profiles planted to grass. Most of the increase was attributed to higher hydraulic conductivity values in top 20 cm of the grass profiles. Infiltration generally decreased with time of year for all the profiles; this was mostly due to decreased hydraulic conductivity in the surface layer. Exceptions were increased infiltration due to cultivation and to drier initial conditions for some cases. Rainfall in September compacted the bare surfaces and results in lower infiltration rates in subsequent tests although it had no significant effect on planted (grass and soybean) profiles. Deep initial water tables resulted in drier profiles and decreased the effect of compressed air on infiltration. This tended to increase infiltration when compared to shallow water table conditions.