Bromide and Nitrate Movement Through Undisturbed Soil Columns
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.
Journal of Environmental Quality
DOI of Published Version
Clay, D. E.; Zheng, Z.; Liu, Z.; and Trooien, T. P., "Bromide and Nitrate Movement Through Undisturbed Soil Columns" (2004). Agronomy, Horticulture and Plant Science Faculty Publications. 179.