POLYACRYLAMIDE EFFECT ON FURROW EROSION AND INFILTRATION

Erosion from furrow irrigated land is a serious problem in southern Idaho and elsewhere in the western United Stares. High molecular weight anionic Polyacrylamide (a water soluble polymer), increases soil aggregate stability and flocculates suspended sediments, thereby reducing sediment detachment and transport in irrigation furrows. Application of 0.7 kg/ha/irrigation of polyacrylamide in irrigation water has reduced furrow erosion by 85 to 99%. In the present work, sediment movement and infiltration were measured in a recirculating furrow infiltrometer with two polyacrylamide treatments. Mean erosion reduction was 70%. Polyacrylamide increased mean infiltration by 30%, probably the result of reduced sediment movement and furrow surface seal formation. Infiltration was inversely related to maximum sediment concentration in the flowing water for both heated and untreated furrows. Farmers who use polyacrylamide must adapt their irrigation management to the higher infiltration to maintain desired irrigation efficiencies.