Does the Soil Have a Tillage Compaction Pan ?
Where the moldboard plow has been a standard, primary tillage tool, compacted “plow pans” can severely reduce downward movement of water through the soil profile. Other tillage implements can also create compacted layers at shallower depth. Soil traffic compaction from increasingly larger, heavier equipment can be a problem as well. After 52 years of a tillage-residue management study initiated in 1931 near Pendleton, a thin, compacted plow pan at about 8 inches depth was found to be the most restrictive layer determining soil water movement. Pikul and other researchers measured a saturated hydraulic conductivity of less than 1.5 inches per day through the plow pan compared to 6 inches per day below the plow pan. Effect of Deep Chiseling Chiseling to a depth of 10 inches to break up a plow pan can effectively increase the rate of water movement. In a field study on a Walla Walla silt loam soil near Pendleton, Zuzel showed that chiseling increased saturated hydraulic conductivity throug
