INFLUENCE OF PLANT UPTAKE ON THE PERFORMANCE OF BROMIDE TRACER

Bromide has been used to study solute transport in unsaturated soils. However, no field studies have addressed the impact of plant uptake on the performance and reliability of Br as a tracer. Field experiments were conducted in a Russet Burbank potato (Solanum tuberosum L.) field on a Plainfield loamy sands oil (mixed, mesic Typic Upidsamment) at the Hancock Research Station in central Wisconsin. At emergence, a 6.8-mm pulse of KBr solution with 15 kg m-3 concentration was banded at the center of each potato row. The results showed that at least 53% of applied Br mass was absorbed by potato plants. Before using Br as a tracer in a field experiment, preliminary laboratory studies should be conducted to determine whether Br uptake and redistribution will be significant under a particular cultivar, Br-application concentration and mode, and water-application scheme.