Nitrate‐Nitrogen and Chloride Movement Through Undisturbed Field Soil

Abstract

AbstractResults are presented from a field study conducted to determine whether large pores represent a major pathway for NO3‐N and Cl movement through undisturbed soil. A solution containing 410 ppm NO3‐N and Cl as KNO3 and KCl was added to three experimental field plots enclosed by wooden barriers to prevent runoff. Initial and final soil samples were taken at various profile depths for ion analyses. Most of the NO3‐N and Cl added in solution moved vertically with the water through the profile. Ion movement was influenced by large soil pores between structural units. A fourth field plot was designed to compare field‐measured NO3‐N and Cl concentrations with theoretical calculations, using time‐dependent water flow velocity and dispersion equations. Soil solution samples were taken for ion analyses. Due to the incomplete mixing of water and ions with all soil pores, theoretical equations did not completely explain the field‐measured NO3‐N and Cl distributions.