Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2003
Publication Date: 11/30/2003
Citation: Flanagan, D.C., Norton, L.D., Peterson, J.R., Chaudhari, K. Using polyacrylamide to control erosion on agricultural and disturbed soils in rainfed areas. Journal of Soil and Water Conservation. 2003. 58(5):301-311. Interpretive Summary: This paper is a summary of research that has been carried out at the National Soil Erosion Research Laboratory since the early 1990's on use of a chemical soil amendment to control soil erosion. The chemical used is called PAM (short for anionic polyacrylamide). PAM worked very well at controlling soil erosion on an agricultural field, from very steep slopes such as highway embankments and landfill caps, and in earthen channels like those found in crop fields or around ponds or dams. We also found that a spraying a liquid solution of PAM was better than just using the dry granular material. Recent and continuing laboratory research is focused on developing equations that represent the impact that the PAM has on reducing erodibility. The research reported here impacts agency personnel, farmers, soil conservationists, etc. looking for new approaches and techniques to control soil erosion by water. In particular, the use of PAM may be a good choice for temporary erosion control during establishment of permanent vegetative cover.
Technical Abstract: Use of anionic polyacrylamide (PAM) as an erosion control soil amendment has been studied at the USDA-ARS National Soil Erosion Research Lab since the early 1990's. An initial field experiment in Indiana using simulated rainfall on a sloping silt loam soil found that 20 kg ha-1 of PAM could reduce sediment loss by over 60% from the first storm event from an agricultural silt loam soil, as well as provide control from rill detachment for inflows of water up to 60 L min-1. More recent studies have examined use of PAM on areas prone to excessive erosion (highway embankments, landfill caps, etc.) to provide control while vegetation is being established. A simulated rainfall study found that 80 kg ha-1 PAM application on a 3:1 silt loam soil constructed fill slope reduced runoff by 86% and soil loss by 99% in a severe storm event (69 mm h-1 for 1 hour) on initially dry soil. The PAM continued to be effective at controlling runoff and soil loss through a series of simulated rainfall applications, reducing runoff by an average of 40% and soil loss by an average of 83% over the entire experiment. Two associated natural rainfall studies found similar erosion control benefits as well as improved vegetation establishment. PAM at 80 kg ha-1 was also found to be effective at preventing earthen channel erosion and degradation on a pre-formed trapezoidal channel at a 1% slope at inflows of water up to 760 L min-1. Application of PAM as a liquid spray that is allowed to dry on the soil surface is more effective than an application of dry PAM granules for immediate erosion control. Recent laboratory experiments have been targeted towards determining the optimal rates of PAM to control rill erosion and minimize cost.