Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 1, 1999
Publication Date: N/A
Interpretive Summary: Furrow irrigation can erode and remove topsoil ten times faster than natural processes can create it. Adding polyacrylamide polymer (PAM) to the irrigation water that flows across furrow-irrigated fields can eliminate over 90% of soil erosion. This study tells irrigators how much PAM to add to irrigation water when using initial, episodic, or continuous PAM application procedures in order to best control furrow erosion or manage water infiltration into furrows. This information helps farmers reduce their production costs, while simultaneously minimizing furrow-irrigation induced sediment and nutrient losses from their fields. The different PAM application strategies evaluated proved to be economical and effective for controlling furrow-irrigation induced erosion over a broad range of field conditions.
Technical Abstract: Adding dilute quantities of moderate-charge-density anionic polyacrylamide (PAM) to furrow irrigation water greatly reduces runoff soil losses and, in some cases, increases net infiltration. We evaluated different strategies for adding PAM to irrigation water to determine which was most effective. PAM was applied to irrigation water in gated irrigation pipe as dry granules, or to furrow inflows as a stock solution. Treatment efficacy varied primarily with irrigation inflow-rate, PAM concentration in irrigation water, duration of furrow exposure, and total PAM applied. The most effective erosion-control treatments either 1) applied an initial dose of PAM at 10 mg/L in irrigation inflows only during the furrow advance period; 2) applied an initial 5 mg/L dose, then reapplied PAM for 5-15 min episodically at similar concentrations; or 3) continually applied 1 to 2 mg/L to irrigation inflows. The full-advance treatment reduced sediment loss by 93%, compared to 60% for the continuous 0.25 mg/L PAM application when slopes were 1-2%. Dry and solution applications controlled erosion about equally.