Bromide movement and uptake under bare and cropped soil conditions at Dire Dawa, Ethiopia

Abstract

The worst-case scenario of NO₃-N leaching is often determined using conservative tracers since it undergoes complex and interdependent transformations in the soil. However, few tracer studies have hitherto been done under cropped soil conditions. In this study, a field experiment was conducted to compare Br- transport under bare and maize planted soil conditions at the experimental site of the Alemaya University, Dire Dawa (East Ethiopia). At the beginning of the experiment, KBr was applied in a solution form. Soil and plant samples were taken several times during the growing season and the concentration of Br- determined. At the end of the experimental period, Br- peak was transported to depths of 900 mm and 1300 mm on bare and maize plots respectively. The percentage of Br- recovery from bare and maize plots was 99.8% and 86.8% respectively. Bromide velocity was slightly higher than the pore-water velocity. The maize plants took up about 8.1% of the applied bromide. The concentration of Br- in the plant tissue decreased as the crop grew while the total uptake was increasing.