Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2002
Publication Date: 12/31/2002
Citation: Peterson, J.R., Flanagan, D.C., Tishmack, J.K. PAM application method and electrolyte source effects on plot-scale runoff and erosion. Transactions of the American Society of Agricultural Engineers. 2002. v. 45. p. 1859-1867. Interpretive Summary: Ways to control soil erosion are very important, as they can help reduce the loss of fertile topsoil and minimize sediment pollution of streams and lakes. This experiment used a chemical called polyacrylamide (also called PAM) to try to control soil erosion on a steep slope under a heavy rainfall. A main objective was to see if the way that the PAM was applied to the soil would make a difference. We found that a liquid solution of PAM sprayed on the soil and allowed to dry was much better at reducing soil loss than an application of dry PAM. For those using PAM, in order to best control erosion due to large rainstorms on a disturbed soil, it is preferable to apply the chemical as a liquid solution. Application method will greatly impact the amount of runoff and soil loss that will occur.
Technical Abstract: Previous research has indicated that polyacrylamide (PAM) soil amendments can be effective in reducing runoff and soil erosion by reducing soil sealing and stabilizing soil structure. Furthermore, the application of a multivalent electrolyte (Ca++) in addition to PAM has been shown to further reduce runoff volume and sediment yield on some soils. A field study was conducted using simulated rainfall to test the effectiveness of method of PAM application (dry or in solution) and the effectiveness of two sources of Ca++ electrolytes (SoilerLime and Nutra-Ash). Results indicated that the SoilerLime applied at 4.3 Mg·ha-1 was as effective as Nutra-Ash applied at 8.0 Mg·ha-1 as an electrolyte source. Treatments using an application of a liquid PAM solution that was allowed to dry on the soil surface were the most effective in reducing total runoff (62% to 76% reduction compared to control) and total sediment yield (93% to 98% reduction compared to control). Spraying of PAM in solution was significantly more effective in controlling runoff and erosion than was the dry granular application for the rainfall events simulated in this study. The slope of regressing sediment yield rate on runoff rate was used as a measure of erodibility. Sprayed PAM treatments dramatically reduced erodibility compared to the control. Dry PAM application did reduce soil erodibility compared to the control but not as dramatically as the sprayed PAM. For intense rainstorms on initially dry soil, we recommend using a sprayed application of PAM for the best erosion control. More research is needed to determine whether this holds true for less intense storms under different field conditions.