Determination of soil hydraulic properties in non-level landscapes

Non-Peer ReviewedMajority of the landscapes in Saskatchewan are non-level. However, specifically designed instruments are not available for the estimation of hydraulic properties of surface soils in non-level landscapes. The purpose of this study was to evaluate the suitability of available tools (tension infiltrometer and double ring infiltrometer) for the estimation of surface soil hydraulic properties in non-level lands. A field experiment was conducted in a loamy soil in Laura, Saskatchewan. Soil surface was prepared to represent 0, 7, 15 and 20% slopes. Infiltration rates were measured using a tension infiltrometer and a double ring infiltrometer. Hydraulic properties were estimated. Steady infiltration rates measured using double ring infiltrometer were not significantly different among slopes (p < 0.05). Saturated hydraulic conductivity and inverse macroscopic capillary length scale predicted from tension infiltrometer were not statistically different (p < 0.05) among the slopes tested indicating that these instruments are suitable for characterization of surface hydraulic properties in hummocky landscapes in Saskatchewan. A computer simulation is planned for further confirmation of these results

Effects of different land use on soil hydraulic properties

Non-Peer ReviewedAn understanding of hydraulic properties of surface soils is needed for sound soil management because it determines the partition of rainfall and snow melt into runoff or soil water storage. The purpose of this study was to evaluate the effects of three land uses (native grassland, brome grassland and cultivated land) on soil physical properties. For each land use, water infiltration rates were measured with a tension infiltrometer at 3, 7, 15, and 22 cm water tensions. Total porosity and macro porosity were determined and hydraulic properties were estimated. The highest total porosity and macro porosity were observed in native grassland while cultivation had significantly reduced macro porosity. At 15 and 22 cm tensions native grassland had significantly lower infiltration rates than cultivated fields while brome grassland had intermediate infiltration rates. Surface soil hydraulic properties differ markedly among land uses, with grasslands having higher saturated hydraulic conductivity. The observations indicate that cultivated soils have lower macroporosity than grassland soils and, therefore, lower infiltration of rain and increased potential for runoff. In contrast, cultivated soils are able to absorb more rainfall and snow melt under unsaturated conditions. Land use changes may alter the water balance of the area by changing the amount of surface runoff and therefore, any changes in existing land use must be done cautiously