NITROGEN AND CHLORIDE DISTRIBUTION AND BALANCE IN A CLAY LOAM SOIL

In field experiments conducted on a poorly drained clay loam soil from 1974 to 1976, inclusive, 21–44% of added chloride was lost from the 0- to 75-cm layer by the end of September, whereas NO3−-N increased in this layer in both the control and fertilized plots. Mineralization during the summer masked any N losses by leaching or denitrification. N losses were highest between late fall and early spring. NO3−-N and chloride tended to show similar distribution patterns in the profile but not necessarily similar leaching losses, since simultaneous denitrification occurred in an adjacent experimental site. Chloride distribution in the profile and leaching losses did not appear to coincide with expectations of typical transport theory, since losses were associated with diffuse bulges near the surface instead of distinct peaks or slugs of chloride moving steadily downward.