Nitrate leaching from systematically tiled potato fields in New Brunswick, Canada.

Drain outflow volumes averaged 75 and 115 nm per unit area in 1987 and 1988, respectively. Considerable drain flow occurred during snowmelt each year before data collection began. Measured NO 3 -N concentrations ranged from 1 to 65 mg L −1 and there were substantial changes in NO 3 -N concentrations within flow events. The flow-weighted average annual nitrate concentrations of the drainage effluent, (NO 3 -N) a f , were ≥10 mg L −1 for potato site-years, regardless of whether the sites were established potato rotation fields or not