Potato land use and nitrate runoff characteristics of two subcatchments of the Wilmot River watershed, Prince Edward Island (PEI), Canada

Abstract

Two subcatchments in the upper reaches of an arable watershed in central Prince Edward Island (PEI), farmed mostly to potatoes (in rotation), were monitored year-round for nitrate runoff. Land management inventories were done every fall and spring and assessed against nitrate runoff through regression analysis for the period 1991 to 2004. Nitrate concentration (averaging approximately 7 mg-L-1 over 14 years) in the outflow varied considerably yearly (standard deviation: 2.76) and monthly (standard deviation: 3.43), and exceeded quality guidelines (of 13 mg-L-1) for aquatic life in freshwaters at about a 6% frequency, averaging a nitrate-dollar loss of $1.70 per hectare per year. © 2008, CAWQ.