Submitted to: Furrow Irrigation Induced Soil Erosion Polyacrylamide Seminar
Publication Type: Other
Publication Acceptance Date: June 6, 1996
Publication Date: N/A
Technical Abstract: Furrow-irrigation-induced soil erosion is a serious threat to sustainable agriculture globally. Field studies have demonstrated that small concentrations of Polyacrylamide (PAM) in irrigation water greatly reduces soil loss from irrigated furrows and increases intake. The PAM used for this application is described, and safety concerns discussed. When used at recommended rates PAM is non-toxic, and it has previous EPA and FDA approval for use in food and water additive applications. PAM effects on furrow irrigation processes are summarized. Optimal PAM treatments reduce furrow soil loss by 94%, increase net infiltration 15%, increase lateral wetting extent 25%, reduce total phosphate losses from fields by 75%, and reduce field losses of some pesticides. PAM's erosion control efficacy decreases as sodium adsorption ratio of the irrigation water increases, but generally it efficacy increases with increasing divalent cation concentration. Studies that examined the fate of PAM added to furrow streams is summarized. During PAM application, runoff from solution-treated furrows contained 6-10 mg/L PAM, while runoff from dry-PAM treated furrows contained 1-6 mg/L. While PAM was being injected into streams, its concentration decreased with distance downstream from the application point. The PAM concentration in solution-treated furrows decreased to the minimum detection limit less than 30 minutes after PAM injection was curtailed. In another study, off-standard PAM treatments were shown to be equally effective as standard approaches, for controlling furrow erosion.