A field experiment, arranged in a four-replication split-plot design, was conducted in a Dark-Red Podzolic (Paleudult) to study infiltration rates, ponding time and initial runoff under conventional and no-tillage methods, plots cultivated with oats (Avena strigosa) and soybeans (Glycine max), using simulated rainfall with constant mean intensities of 63.0 and 87.0 mm/h. A small rainfall simulator with 80-100 and 80-150 Veejet nozzles was used, and the test sites had 0.81 m². Smith's model was adjusted to the observed data. Ponding times and initial runoff times decreased with increasing rain intensity, being always smaller for no-tillage. Accumulated and constant rate of infiltration were greater for no-tillage. Constant rate of infiltration decreased with increasing rain intensity for conventional tillage, with no differences detected for no-tillage. The exponent b of the infiltration model showed a small variation and constant infiltration rates were slightly superestimated.
water movement; infiltration rate; physical properties; soil management and conservation