CHISEL TILLAGE, FURROW DIKING, AND SURFACE CRUST EFFECTS ON INFILTRATION

Chisel tillage and furrow dikes (small earthen dams constructed in the furrow) am commonly used to increase infiltration and soil water storage in semiarid regions. Data quantifying the combined influences of these practices are limited. Our objective was to determine the effects of chisel tillage, furrow dikes (with and without ponding), and drop impact or surface crusts on infiltration. Infiltration rate (IR) and cumulative infiltration (CI) into an Olton day loam (fine, mixed, thermic Aridic Paleustoll) were measured by applying water at 65 and 80 mm h-1 for 1 h using a rotating-disk-type rainfall simulator. Furrow dikes increased infiltration under both ponded and nonponded conditions. Cumulative infiltration was higher when raindrop impact energy was dissipated and, to some extent, when crusts were removed. Infiltration rate at the end of water application was lower with raindrop impact than when raindrop impact was eliminated; however, there were no differences in the final IR between the initially crusted and uncrusted soils. There were no differences in infiltration between chisel-disk and disk tillage measured during the mid growing season. Furrow dikes not only detain water on the surface to provide more time for infiltration, but also increase infiltration through increased hydraulic head and additional tillage performed during dike installation or by moving loose soil from the furrow into the dikes. Our data do not support using the same hydraulic-conductivity value for both diked and undiked field conditions, which may cause underestimation of water conservation in furrow-diked fields.