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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #188141

Title: INHIBITING WATER INFILTRATION INTO SOILS WITH CROSS-LINKED POLYACRYLAMIDE: SEEPAGE REDUCTION FOR IRRIGATED AGRICULTURE

Author
item Lentz, Rodrick

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2007
Publication Date: 7/29/2007
Citation: Lentz, R.D. 2007. Inhibiting water infiltration into soils with cross-linked polyacrylamide: Seepage reduction for irrigated agriculture. Soil Science Society of America Journal. 71:1352-1362.

Interpretive Summary: High water infiltration rates in unlined canals, reservoirs, and the inflow end of furrows relative to outflow ends result in excessive water application, which increases leaching losses of water, nutrients, and agrochemicals there, and reduces furrow irrigation application uniformity. Seepage from irrigation channels can be nearly eliminated by lining them with concrete or membranes of rubber, or plastic, but these methods are costly, and cannot be applied to irrigation furrows. This laboratory study evaluated the use of cross-linked, anionic, polyacrylamide hydrogel (XPAM) for reducing infiltration and seepage losses though soil. This study showed that water seepage through many soils can be reduced by 87 to 94% by mixing in 0.5% to 1% XPAM into a 1-inch layer of soil. The 0.5% XPAM treatment applied to inflow-end miniflume soils successfully altered spatial seepage patterns in miniflumes, relative to controls. These XPAM treatments could potentially be used to increase the uniformity of furrow water applications and reduce seepage from unlined irrigation ponds and canals.

Technical Abstract: High water infiltration rates in unlined canals, reservoirs, and the inflow end of furrows relative to outflow ends result in excessive seepage losses and reduced furrow irrigation application uniformity. We evaluated the use of cross-linked, anionic, polyacrylamide hydrogel (XPAM) for reducing infiltration and seepage losses though soil. Soil column experiments measured effective saturated hydraulic conductivity under constant-head conditions. Treatment regimes included five soils treated with 0 to 10 g/kg XPAM, a silt loam soil treated with 0 to 5 g/kg XPAM, while varying soil NaCL, XPAM granule-sizes, or treated soil layer thicknesses, and miniflume tests. The 21-h effective conductivity of all soils except the loamy sand decreased curvilnearly with increasing XPAM rate, with maximum reductions for 5 and 10 g/kg XPAM rates of 87 to 94%, relative to controls. The fine-grained XPAM was significantly more effective than the coarser-grained XPAM, and treated soil-layer thickness had no significant effect on the XPAM’s seepage reduction efficacy. The 5 g/kg XPAM treatment applied to inflow-end miniflume soils significantly decreased the “furrow-stream” advance period and reversed the spatial infiltration patterns observed in miniflumes, relative to controls. These XPAM treatments could potentially be used to increase the uniformity of furrow water applications and reduce seepage from unlined irrigation ponds and canals.