Bromide and Nitrate Movement Through Undisturbed Soil Columns

Document Type

Article

Publication Date

1-2004

Abstract

Field experiments often assume that Br−, 14NO 3–N, and 15NO 3–N have similar leaching kinetics. This study tested this assumption. Twenty-four undisturbed soil columns (15-cm diameter) were collected from summit–shoulder, backslope, and footslope positions of a no-tillage field with a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation. Each of the landscape positions had a different soil series. After conditioning the columns with 4 L of 0.01 M CaCl2 (2 pore volumes), 15N-labeled Ca(NO3)2 and KBr were applied to the soil surface and leached with 4 L of 0.01 M CaCl2 Leachate was collected, weighed, and analyzed for NO 3–N, NH4 +–N, 15N, 14N, and Br The total amount of 15NO 3–N and 14NO 3–N collected in 1000, 2000, and 3000 mL of leachate was similar. These data suggest that 15N discrimination during leaching did not occur. Bromide leached faster through the columns than NO 3–N. The more rapid transport of Br than NO 3–Nwas attributed to lower Br (0.002 ± 0.036 mg kg−1) than NO 3–N (0.17 ± 0.03 mg kg−1) sorption. Results from this study suggest that (i) if Br is used to estimate NO 3–N leaching loss, then NO 3–N leaching losses may be overestimated by 25%; (ii) the potential exists for landscape position to influence anion retention and movement in soil; and (iii) 15N discrimination was not detected during the leaching process.

Publication Title

Journal of Environmental Quality

Volume

33

Issue

1

First Page

338

Last Page

342

DOI of Published Version

10.2134/jeq2004.3380

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