Rev. Bras. Ciênc. Solo.2021;45:e0210027.
Estimating lateral flow in double ring infiltrometer measurements
Daniel Boeno 
, Paulo Ivonir Gubiani , Quirijn de Jong Van Lier , Rodrigo Pivoto Mulazzani
29/jul/2021
DOI: 10.36783/18069657rbcs20210027
Resumo Gráfico
Destaques
Lateral flow may occur in double ring infiltrometer measurements (DRI)
Steady infiltration rate was measured with DRI in different soil layers
90% of the flow in DRI in the surface layer referred to lateral flow
Richards equation-based simulation of vertical flow supported this finding
ABSTRACT
The steady infiltration rate of soil profiles is commonly determined for irrigation and soil conservation planning, but the divergence of methods reduces the reliability of measurements. In this study, the steady infiltration rate measured with a double ring infiltrometer (isr-dri) in different layers of a soil profile was compared between layers and with the steady vertical saturated flow rate estimated by the Richards equation (isr-hy). The measurements of isr-dri at the top of the A, E, and Bt horizons were compared to each other and also compared with the isr-hy to detect the occurrence of lateral flow in double ring infiltrometer measurements. The isr-dri in the A horizon (236 mm h-1) was around 10 times higher than in the Bt horizon (20 mm h-1), which implies in a lateral flow of almost 90 % in the surface horizon. The occurrence of lateral flow in double ring infiltrometer measurements was also shown by comparing isr-dri with the vertical saturated flow rate estimated with the Richards equation, isr-hy. The main conclusion is that isr-dri measured at the soil surface overestimates the steady infiltration rate of soil profiles when underlying horizons are less permeable and more restrictive to water flow. In these cases, the use of an effective saturated hydraulic conductivity of the soil profile would imply inaccurate planning of drainage, irrigation, and soil conservation designs.
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