Surface microrelief and agrichemical placement influence agrichemical movement through soil. This study determined if anhydrous ammonia shank placement influenced atrazine movement in a ridge tillage system. Atrazine and Br− were broadcast over the plot or banded on the ridge while N fertilizer was Injected into the ridge or valley. Rainfall (17 cm) was applied and leachate was collected incrementally from grid lysimeters placed 75 cm below the soil surface. Amounts of atrazine and Br− in leachate and postrainfall soil atrazine distribution were determined. The injection slot created by fertilizer application influenced chemical movement. When atrazine and the fertilizer injection slot overlapped, atrazine movement through the soil was enhanced. These data suggest that herbicide applications and fertilizer injection slots that are not covered should not overlap due to increased potential for movement.
