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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #79250
Title: PRELIMINARY RESULTS USING POLYACRYLAMIDE WITH SPRINKLER IRRIGATION

Author
item Bjorneberg, David - Dave
item Aase, J
item Sojka, Robert

Submitted to: Idaho Winter Commodity School Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Application rates often exceed soil infiltration rates on linear move irrigation systems and near the outside end of center pivot systems, which causes ponding and runoff. Preliminary laboratory results showed that adding a small amount of polyacrylamide (PAM) to the irrigation water can reduce runoff. Applying 2 pounds per acre of PAM with irrigation water reduced runoff and soil erosion by 75% compared to untreated irrigations. Reducing runoff potentially increases irrigation uniformity, which is especially important when chemicals and fertilizers are applied through an irrigation system. Applying PAM should also allow higher irrigation rates or depths without causing runoff, resulting in faster field coverage, which is particularly beneficial for linear move irrigation systems.

Technical Abstract: Small amounts of polyacrylamide (PAM) added to irrigation water have successfully reduced furrow erosion up to 99%. A laboratory study was initiated in Fall 1996 at the Northwest Irrigation and Soils Research Laboratory near Kimberly, Idaho to identify optimum PAM concentrations and rates for reducing runoff and soil erosion under moving irrigation systems. The goal was to develop guidelines for PAM application through center pivot and linear move irrigation systems. Six soil boxes, 1.22 m wide by 1.52 m long by 0.15 m deep, were filled with a silt loam soil and set at a 2.5% slope. A single oscillating nozzle applied 20 mm of solution to each soil box at 80 mm/hr for 15 minutes. PAM concentration in the irrigation water was 0, 5 or 10 ppm, resulting in 0, 1 or 2 kg/ha application rates, respectively.Average runoff was 4.5 mm and soil loss was 160 kg/ha for untreated soil boxes. Adding 10 ppm PAM to the irrigation water reduced runoff and soil loss from the soil boxes to 1.0 mm and 40 kg/ha, respectively. All boxes were irrigated with plain water two weeks after the first irrigation. Runoff and soil loss from the untreated soil was similar to the first irrigation (4.3 mm and 123 kg/ha). By contrast, the 5 and 10 ppm treated soil had approximately half the runoff and soil loss as the untreated soil during the second irrigation (5 ppm 2.5 mm and 50 kg/ha; 10 ppm 2 mm and 34 kg/ha). These preliminary results indicate that applying PAM through a sprinkler irrigation system should allow higher irrigation rates or depths without causing runoff, resulting in faster field coverage, which is particularly beneficial for linear move irrigation systems.