PAM APPLICATION METHOD AND ELECTROLYTE SOURCE EFFECTS ON PLOTSCALE RUNOFF AND EROSION

Abstract

Previous research has indicated that polyacrylamide (PAM) soil amendments can be effective in reducing runoffand soil erosion by reducing soil sealing and stabilizing soil structure. Furthermore, the application of a multivalentelectrolyte (Ca++) in addition to PAM has been shown to further reduce runoff volume and sediment yield on some soils. Afield study was conducted using simulated rainfall to test the effectiveness of the method of PAM application (dry or insolution) and the effectiveness of two sources of Ca++ electrolytes. Treatments using an application of a liquid PAM solutionthat was allowed to dry on the soil surface were the most effective in reducing total runoff (62% to 76% reduction comparedto control) and total sediment yield (93% to 98% reduction compared to control). Spraying of PAM in solution wassignificantly more effective in controlling runoff and erosion than was the dry granular application for the rainfall eventssimulated in this study. The slope of regressing sediment yield rate on runoff rate was used as a measure of erodibility. SprayedPAM treatments dramatically reduced erodibility compared to the control. Dry PAM application also reduced soil erodibilitycompared to the control, but not as dramatically as the sprayed PAM. For intense rainstorms on initially dry soil, werecommend using a sprayed application of PAM for the best erosion control. More research is needed to determine whetherthis holds true for less intense storms under different field conditions.