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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #110050
Title: SPRINKLER IRRIGATION RUNOFF AND EROSION CONTROL WITH POLYACRYLAMIDE

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

Submitted to: Decennial National Irrigation Symposium
Publication Type: Proceedings
Publication Acceptance Date: 4/17/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Center pivot irrigation systems are used on about one-third of the irrigated land in the United States. However, runoff can be a problem when water application rate exceeds the infiltration rate of the soil, which often occurs under the outer spans of center pivots. We found that applying polyacrylamide (PAM) at 2 to 4 lb/a with irrigation water reduced runoff and soil loss during laboratory simulations. Applying PAM with multiple irrigations maintained runoff and erosion control longer than applying PAM with a single irrigation, even though both treatments received the same total amount of PAM. Seventy percent residue cover more effectively controlled runoff and erosion than PAM, while 30% cover was about as effective as PAM. A single PAM application may be adequate for a critical irrigation (i.e. seedling emergence), but multiple PAM applications are necessary for season-long benefits. Tillage and residue management practices should be considered before PAM is applied to control runoff under sprinkler irrigation. These results, however, could vary with irrigation water quality and soil chemistry.

Technical Abstract: Applying polyacrylamide (PAM) with furrow irrigation water dramatically reduces soil erosion and frequently increases infiltration. We conducted three studies to determine if PAM controlled runoff and soil erosion under sprinkler irrigation. Our tests were conducted in the laboratory on 1.5 m long, 1.2 m wide and 0.15 m deep soil boxes. Water was applied at 80 mm/h with an oscillating nozzle irrigation simulator. Applying 2 to 4 kg/PAM ha significantly reduced runoff and soil erosion during the irrigation when PAM was applied. These beneficial effects decreased with each subsequent irrigation. Multiple PAM applications maintained runoff and erosion control longer than a single application, even though both treatments received the same total amount of PAM. Seventy percent residue cover more effectively controlled runoff and erosion than PAM, while 30% cover was about as effective as PAM. A single PAM application of 2 to 4 kg/ha may be adequate for a critical irrigation (i.e. seedling emergence), but multiple PAM applications are necessary for season-long benefits. Tillage and residue management practices should be considered before PAM is applied to control runoff under sprinkler irrigation. These results, however, could vary with irrigation water quality and soil chemistry.