6533b831fe1ef96bd1299a03

RESEARCH PRODUCT

Testing steady-state analysis of single-ring and square pressure infiltrometer data

Massimo IovinoJian-bin LaiVincenzo Bagarello

subject

Single-ring pressure infiltrometer0208 environmental biotechnologySquare infiltrometerSoil ScienceSoil scienceNumerical simulation04 agricultural and veterinary sciences02 engineering and technologyInfiltration (HVAC)020801 environmental engineeringSaturated soil hydraulic conductivityHydraulic conductivityLoamSoil water040103 agronomy & agriculture0401 agriculture forestry and fisheriesInfiltrometerSpatial variabilitySaturation (chemistry)PondingMathematics

description

Testing reliability of the saturated soil hydraulic conductivity, Ks, estimated by applying the steady-state single-ring (SR) model to the quasi steady-state infiltration rates obtained with a single-ring pressure infiltrometer (PI) increases confidence in the estimated Ks values. Determining a means to estimate Ks from infiltration data collected with a square infiltrometer allows the use of sources of different shapes. Using numerically simulated infiltration rates for six homogeneous soils ranging in texture from sand to silty clay loam, this investigation suggested an overall good performance of the SR model, with estimated Ks values differing by not more than 25% from the true values for the 90% of the 96 considered runs. Larger errors were generally obtained for the silty clay loam soil. Even in this case, however, a small ring radius (0.038. m), a relatively high initial soil water content (initial effective saturation. =. 0.4) and a relatively high depth of ponding (0.10. m) allowed the obtainment of accurate predictions of Ks (error. =. 13%) with a run of practically sustainable duration (4. h). The SR model was also usable to analyze quasi steady-state infiltration data collected with a square infiltrometer when infiltration was assumed to occur through a circular source having the same area of the square infiltrometer. With this assumption, the estimates of Ks differed from the true values by not more than a practically negligible 16%. The results of this investigation should help better interpret Ks values obtained with the PI and also improve the experimental methodology, depending on the soil. Moreover, a wider applicability of the infiltrometer techniques, i.e. not limited to a circular source, can be expected. Soil heterogeneity should be taken into account in the future since heterogeneity is common in the field.

https://doi.org/10.1016/j.geoderma.2015.07.002