Improving water infiltration and ameliorating soil crusting with polyacrylamide

Some soils have a tendency to form strong surface crusts. These crusts hinder seedling emergence and water infiltration and promote run-off and erosion. Crusting is often worsened by irrigation with tow-quality water such as high-sodium wastewater. Polyacrylamide (PAM) soil treatment may be useful for improving the effectiveness of irrigation with low-quality water. A series of lab and field studies was performed. In a lab study, columns of soil treated with various levels of PAM were exposed to a high-sodium wastewater and simulated rainwater. PAM dramatically improved hydraulic conductivity in the columns, but effects diminished over 8 weeks. In a field study, soil was furrow-irrigated with wastewater. PAM injected into the wastewater during irrigation resulted in significantly greater infiltration as tested several weeks after the last irrigation. In another field study PAM sprayed over the soil surface significantly and consistently reduced the strength of soil crusts on a non-irrigated field. PAM appears to have practical potential for ameliorating soil crusting and improving infiltration.