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 ( i 0 ) varying by approximately four times, were less variable than the means of both the final ( i f ) and the mean ( i med ) infiltration rates, varying by 13 and nine times, respectively. The means of all considered parameters decreased as the antecedent soil water content ( θ i ) increased but the θ i effect was stronger for i 0 (coefficient of determination, R 2 = 0.84) than both i f and i med ( R 2 = 0.55-0.68). With reference to these last two parameters, θ i effects were significant for the lowest measured values ( R 2 = 0.63-0.76) but not for the highest ones ( R 2 = 0.12-0.13). Particularly small i f and i med 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 θ i values is recommended to obtain the most complete information about temporal variability of infiltration rates.