Comparing a Double-Ring Infiltrometer with the DualHead Infiltrometer
Decagon recently compared the DualHead Infiltrometer (15.24 cm inner ring diameter) with a double-ring infiltrometer (15.24 cm inner ring, 30.48 cm outer ring diameter) We conducted the test at 7 locations distributed across a turf field (Fig. 1).
Figure 1. Locations of DHI and double-ring Infiltrometer measurements for comparison.
Measurements were collected at the same time within the same 1 m2 area. The DualHead and double-ring infiltrometer measurements compared well, except in cases where the flow was dominated by large macropores (Fig. 2).
Figure 2. 1:1 plot of Kfs measurements from double-ring infiltrometer (y-axis) and DualHead Infiltrometer (x-axis).
Large macropores primarily dominated measurements at locations SF3 and SF4. At these locations, we hypothesise that the amount of force required to install the double-ring infiltrometer disturbed the structure of the soil and crushed the macropores. Because of this disturbance, the field saturated hydraulic conductivity (Kfs) from the double-ring infiltrometer was 2 orders of magnitude lower than the DHI measurements (Table 1).
Table 1. Field saturated hydraulic conductivity values from double-ring infiltrometer and DHI.
Overall, the two methods provided similar estimates of saturated hydraulic conductivity, except in cases where there are large structural macropores that can be destroyed when subjected to the amount of force required to install the double-ring infiltrometer