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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #110051
Title: POLYACRYLAMIDE FOR SURFACE IRRIGATION TO INCREASE NUTRIENT USE EFFICIENCY AND PROTECT WATER QUALITY

Author
item Lentz, Rodrick
item Sojka, Robert
item ROBBINS, CHARLES - USDA-ARS (RETIRED)
item Kincaid, Dennis
item Westermann, Dale

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Polyacrylamide (PAM) polymer is an economical and effective material that nearly eliminates erosion and sediment loss produced during furrow irrigation, where water is supplied to crops in small streams that flow across the field. PAM inhibits erosion and permits larger furrow streams, which advance across fields more quickly and result in a more uniform water application. This work demonstrates that PAM-treatment also helps hold plant nutrients on the field and in the soil. Costly fertilizers and soil amendments applied to fields are used more efficiently by crops under PAM-treated irrigation because the nutrients stay in the plant rooting zone. Though PAM can increases the amounts of water that infiltrate into furrows, this study shows that the extra infiltrated water is made available to the crop and does not increase removal of nutrients in subsurface drainage water. PAM effectively prevents soil nutrient losses, increases nutrient-use efficiency, and decreases excess nutrient loads in irrigation return flows and receiving surface waters.

Technical Abstract: Furrow irrigation systems produce greater runoff, erosion, and deep percolation losses than sprinklers. Nutrient losses are associated with sediment in runoff and can be minimized by eliminating erosion. Anionic polyacrylamide (PAM) is applied to advancing furrow streams at a concentration of 10 mg/L. We hypothesized that this treatment would reduce runoff losses of sediment, molybdate-reactive-P (MRP), total P, Nitrate-N, and chemical oxygen demand (COD). PAM often increases furrow infiltration, however, we hypothesized that because it permits higher initial inflows, PAM would not increase nutrient leaching relative to conventional irrigation. To test the first hypothesis, all treatments had the same inflow regime. For hypothesis two, control inflows were a constant 15 L/min; PAM treated inflows were cut back from 45 to 15 L/min after furrow advance. PAM increased infiltration and decreased runoff, particularly early in the irrigations. PAM reduced 12-h cumulative sediment losses in runoff by 90%, MRP by 87%, total P by 92%, and COD by 85%, relative to control furrows. PAM had no field-wide, season-long effect on cumulative amounts of water, Nitrate-N or Cl leached. PAM technology effectively prevented soil nutrient losses, increased nutrient-use efficiency, and decreased N and P loads in irrigation return flows and receiving surface waters.