Relative Movement of Bromide and Nitrate Through Soils

Abstract Miscible displacement experiments were conducted with eight different surface soils (0–15 cm depth) and their associated subsoils (61–76 cm depth). Results indicate that the movement of bromide relative to that of nitrate (0.005 N salts) is identical in subsoils but variable in surface soils. Differences in relative movement of the two anions may be attributed to microbial activity involving nitrate. With the exception of 5% anion sorption in a Greenville subsoil, anion exclusion values ranged from 5 to 39%, indicating the anions were moving 1.05 to 1.64 times as fast as they would if they had been uniformly associated with all the soil water. The results support the view that bromide has utility for following the potential path of nitrate movement through soils.