Infiltration rate and hydraulic conductivity measured with rain simulator and disc permeameter on sloping arid land

The objective of the study was to examine relationships between steady infi ltration rates and hydraulic conductivity obtained with drip infiltrometer and disc permeameter on moderately to strongly sloping land. The disc perme ameter is generally used for measurements on horizontal or slightly sloping surfaces but is easier to handle in the field than the drip infiltrometer. At two sites on natural prairie in Central Chile, a portable drip infiltro meter was used to measure infiltration rate and simulate rain, including th e impact of falling drops, using two strategies: (1) DIH-starting with a hi gh application rate and decreasing it until a minimal application rate that generated steady runoff was obtained, and, (2) DIL-starting with a low rat e and increasing it until steady infiltration rate that did not increase wa s ensured. In parallel, a disc permeameter was used to determine infiltrati on rate (PI) and hydraulic conductivity (K) at different supply water press ure heads (psi). Infiltration rates obtained with the DIL strategy were on average only 46% of those of DIH. Application intensity, particularly at th e start of events, was crucial in the impact on structural changes in the s oil surface. The drip infiltrometer DIH was larger than or equal to the dis c permeameter PI and K at psi = -20 mm. The DIL corresponded with PI at psi = -40 mm and -60 mm and K at psi = -30 mm. Disc permeameter was shown to b e a useful tool as an alternative to drip infiltrometer to determine infilt ration rates even on moderately to strongly sloping land, if measurements w ith the former are carried out at some predefined psi as identified in this article.