HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lentz, R. D. Search for Related Content PubMed Articles by Lentz, R. D. Agricola Articles by Lentz, R. D. Related Collections Irrigation Laboratory Column Studies Infiltration Hydraulic Conductivity

SOIL & WATER MANAGEMENT & CONSERVATION

Inhibiting Water Infiltration into Soils with Cross-linked Polyacrylamide: Seepage Reduction for Irrigated Agriculture

USDA-ARS, Northwest Irrigation and Soils Research Lab., 3793 N 3600 E, Kimberly, ID 83341

^* Corresponding author (lentz{at}nwisrl.ars.usda.gov).

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. This study evaluated the use of cross-linked, anionic, polyacrylamide hydrogel (XPAM), a water-absorbing, swellable polymer solid, for reducing infiltration and seepage losses though soil. Experiments 1 and 2 measured the influence of soil treatments on seepage rate in soil columns under constant-head conditions: Exp. 1 treated five soils with 0, 2.5, 5, and 10 g kg^–1 XPAM; Exp. 2 applied combined XPAM (0–5 g kg^–1) and NaCl (0–5.1 g kg^–1) treatments to a silt loam soil, and separately tested the effect of XPAM granule size and treated soil layer thickness on seepage rate. In Exp. 3, a miniflume was used to determine how a 5-mm-thick, XPAM-treated (0–5 g kg^–1) soil layer at the inflow end of the "minifurrow" influenced water distribution. The 21-h seepage rates of all soils except the loamy sand decreased curvilinearly with increasing XPAM rate, with maximum reductions of 87 to 94 0.000000or 5 and 10 g kg^–1 XPAM rates, relative to controls. The <300-µm-diam. XPAM granules were significantly more effective than the coarser grained XPAM for reducing seepage, and reducing the thickness of the treated soil layer from 71 to 24 mm had no significant effect on the seepage reduction obtained with XPAM. The 5 g kg^–1 XPAM treatment applied to inflow-end miniflume soils significantly decreased the "furrow-stream" advance period and reversed the 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.

Abbreviations: EC, electrical conductivity • ESP, exchangeable sodium percentage • SAR, sodium adsorption ratio • WSPAM, water-soluble, anionic polyacrylamide copolymer • XPAM, cross-linked, anionic polyacrylamide hydrogel