Comparison of Tracer Mobilities under Laboratory and Field Conditions
1989
Everts, Christopher J. | Kanwar, Rameshwar S. | Alexander, E Calvin | Alexander, Scott C.
Transport of bromide, nitrate, lithium, and Rhodamine WT were compared in a repacked soil column and in a tile drained in a cropped field. Breakthrough of lithium and Rhodamine WT in a soil column was delayed by adsorption as compared to nitrate and bromide in the same column. When applied with irrigation water above a tile drain line, concentrations of all the tracers peaked in tile water 70 min after the start of an irrigation, then declined as irrigation continued. Tile flow responded to irrigation by increased flow and increased tracer concentration within 25 min after the start of an irrigation. Total percentage of tracers reaching tile flow from two tracer irrigations were 3.0, 2.5, 0.46, and 0.15%, respectively, of the nitrate, bromide, lithium, and Rhodamine WT applied with irrigation water. Of these losses, 67% of the cation-exchanged lithium and 83% the adsorbed Rhodamine WT removed in tile flow during 56-h of tile flow did so within 1 h after the irrigation ended. Proportion of nitrate and bromide losses in tile flow during the same time period were 40 and 35%, respectively. Journal paper no. J-13212 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project no. 2792.
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