Effects on infiltration of different wetting methods: an investigation through two-stage beerkan runs in a conventionally tilled and a no-tilled loam soil

Soil water infiltration implies wetting of the porous medium but the manner in which the soil is wetted can vary. The multi-height beerkan (MHB) infiltration experiment allows investigating in the field the soil hydrodynamic behavior by distinguishing between wetting and water mechanical impact effects on infiltration rate, ir. In this investigation, the MHB method with three heights of water pouring (low, L ≈ 0.03 m; intermediate, M = 1.0 m; high, H = 2.0 m) was applied to evaluate wetting alone (L) and wetting plus water impact (M and H) effects on ir. Two-stage MHB runs without interruption (LL, ML and HL) were performed and the effects on ir were evaluated for both a conventionally tilled (CT) and a no-tilled (NT) loam soil. Infiltration rates were consistently higher in the NT soil than the CT soil (on average, 533 mm/h against 230 mm/h), regardless of whether infiltration was established by wetting alone or by wetting combined with water mechanical impact, probably due to a higher presence of relatively large and water stable aggregates under undisturbed soil conditions. An initial wetting with some water mechanical disturbance at the soil surface made the subsequent classical beerkan infiltration run more stable, especially in CT soil, and slower than that established in a wetted soil without intentional disturbance. Infiltration rates appeared not to depend much on the manner in which water was applied for large values of the overall dissipated gravitational potential energy. In conclusion, for a given soil, the water impact effects on the soil surface vary with soil management and the MHB method appears suitable for capturing these effects under hydrologically relevant field conditions.