Comparison of Single- and Double-Ring Infiltrometer Methods on Stony Soils

Infiltration measurements to determine the field saturated hydraulic conductivity (K-fs) in arid lands are often plagued by large variations that can be attributed to soil heterogeneity, the measurement method, the number of replications, and the K-fs calculation method used. This study addressed the question of how comparable are two different measurement methods, the single-ring infiltrometer (SR) and double-ring infiltrometer (DR), when applied at three locations in a semiarid part of Chile that show moderate (15%) to high (55%) stoniness. Additionally, K-fs variations due to different calculation methods for the same measurement method were thoroughly investigated, considering nine methods for the SR and 10 methods for the DR. Results showed that different calculation techniques gave some times significantly different estimates of K-fs when using the same data set, and those relative differences were conserved between measurement locations. When comparing the same calculation technique for both SR and DR, both methods gave equivalent K-fs estimates for each location. The SR infiltration measurements were modeled better using a transient approach, while infiltration models considering steady state performed better with the DR.