| Popis: |
Ring infiltration methods are widely used for field soil hydraulic characterization. Establishing factors affecting these methods is necessary to interpret the collected data. The height from which water is poured on the soil surface is known to influence infiltration in a sandy-loam soil, since low (L, height of water pouring 0.03 m) runs yielded higher infiltration rates than high (H, 1.5 m) runs in previous investigations. The impact of water pouring height on infiltration rates seems to vary with the antecedent soil water content, θi. In this investigation, height effects on infiltration were tested for an initially very wet sandy-loam soil. Two-stage infiltration runs differing by the height of water pouring in the second stage of the run (L1L2 and L1H2 runs) were carried out. With the L1L2 runs, the final infiltration rate and the duration of the second stage were 2.2 times lower and longer, respectively, than the corresponding values of the first stage. With the L1H2 runs, the corresponding factors of difference were 5.5 and 4.5, respectively. Therefore, the perturbation due to a high height of water pouring was also detectable in initially wet soil conditions. Disturbance due to a high height of pouring was reduced in more compact soil conditions. In conclusion, the low-high infiltration run methodology seems usable in general to detect the effects of the water application procedure on infiltration. The dry soil bulk density appears useful to predict disturbance effects caused by the infiltration run. |
