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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #88104

Title: SPRINKLER IRRIGATION RUNOFF AND EROSION CONTROL WITH POLYACRYLAMIDE -- LABORATORY TESTS

Author
item AASE, J
item Bjorneberg, David - Dave
item SOJKA, ROBERT

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Many productive semiarid and arid soils are prone to sprinkler irrigation-induced erosion and surface sealing. About 1 lb/acre of Polyacrylamide a long-chain organic polymer (PAM) in furrow irrigation advance water greatly reduces erosion. Polyacrylamide applied through sprinkler irrigation systems is less studied. We hypothesized that PAM will produce erosion control, water infiltration, and provide soil aggregate stability benefits when applied via sprinkler irrigation. We used a silt loam soil placed in 5 foot x 1.2 foot x 0.5 foot steel boxes with 2.4% slope. The boxes were located in the hydraulics laboratory. We pumped water and PAM-treated water to an oscillating irrigation nozzle that was 10 feet above the soil. An equivalent of about 2 lbs/acre PAM in the first irrigation reduced runoff 70% and soil loss 75%. Effects of PAM diminished in subsequent water-only irrigations. Polyacrylamide stabilized the soil surface. Infiltration was greater on PAM treated soils than on non-treated soils. Laboratory sprinkler irrigation tests are ongoing to determine how PAM affects runoff and erosion control using different soil types, slopes and water quality. Field application of laboratory results is being tested on commercial farms using large-scale commercial sprinkler systems.

Technical Abstract: Many productive semiarid and arid soils are prone to sprinkler irrigation-induced erosion and surface sealing. About 1 kg/ha Polyacrylamide (PAM) in furrow irrigation advance water greatly reduces erosion. Less studied is PAM applied in sprinkler irrigation. We hypothesized that PAM will produce erosion control, water infiltration, and provide aggregate stability benefits when applied via sprinkler irrigation. Screened (6.4 mm) Rad silt loam (coarse silty, mixed, mesic Durixerollic Camborthids) was placed in 1.5 m x 1.2 m x 0.2 m steel boxes with 2.4% slope. An oscillating irrigation nozzle, 3 m above the soil, produced a median drop size of 1.2 mm (about 25 J/kg). A 20 mm water depth was applied in each of three irrigations with PAM at 0, 1, 2, 4, and 6 kg/ha in the first irrigation. In a second test we applied 0, 2, and 4 kg/ha PAM in 8 mm water in the first irrigation, followed by two 20 mm irrigations. Two kg/ha PAM in the first 20 mm irrigation reduced runoff 70% and soil loss 75%. Polyacrylamide in 8 mm water controlled runoff and erosion less effectively than PAM in 20 mm water. Polyacrylamide in 20 mm irrigation did not affect tension infiltration; PAM in 8 mm irrigation resulted in a doubling of infiltration following the third irrigation. Wet aggregate stability following the first irrigation was greater on PAM treatments than on check. With 2 kg/ha PAM in 20 mm irrigation aggregate stability was 55%, in 8 mm, 77%. Tests are ongoing to refine application strategies and to test PAM on different soils. Sprinkler-applied PAM is also being tested at field-scale on commercial farms.