A four-year monitoring of beerkan infiltration rates in a sandy-loam soil

Long-term investigations on temporal variability of infiltration rates are important for characterizing the porous medium but they are challenging and infrequent. Infiltration rates were measured in a sandy-loam soil by performing 16 beerkan infiltration runs on 14 sampling dates during a nearly four-year period. The means of the initial infiltration rates (i0) varying by approximately four times, were less variable than the means of both the final (if) and the mean (imed) infiltration rates, varying by 13 and nine times, respectively. The means of all considered parameters decreased as the antecedent soil water content (θi) increased but the θi effect was stronger for i0 (coefficient of determination, R2 = 0.84) than both if and imed (R2 = 0.55-0.68). With reference to these last two parameters, θi effects were significant for the lowest measured values (R2 = 0.63-0.76) but not for the highest ones (R2 = 0.12-0.13). Particularly small if and imed values were obtained in initially very wet soil conditions. The antecedent soil water content can be expected to strongly control infiltration rates in a sandy-loam soil. Sampling the widest possible range of θi values is recommended to obtain the most complete information about temporal variability of infiltration rates.