Atrazine fate on a tile drained field in northern New York: a case study

Only by understanding the transport and degradation mechanisms of atrazine on farms can measures be taken to minimize atrazine concentrations that reach natural environments. The fate of atrazine on a tile drained farm in northern New York during the spring was followed. The largest stream was sampled as well as individual tile lines from one field after snowmelt began in March 1994, until the flow ceased in early June 1994. Prior to the first application of atrazine on the farm in 1994, atrazine concentrations in the stream ranged between 0 and 0.4 μg L −1. Immediately following an 0.8 inch rainfall event, 6 days after the application of 1.4 kg of atrazine on 1 ha of a tile drained field, atrazine concentrations at a tile line outlet feeding into the stream reached 34.5 μg L −1 After mixing with other inflows, the atrazine concentration in the stream was 6.4 μg L −1 The atrazine concentration decreased along the 1450 foot stream. Analysis of eight tile lines which drained a research field showed a direct correlation between increased flow rates with increased atrazine concentration. No-tillage practices may lead to slightly higher concentrations of atrazine in the tile lines.