LAUSR

Nitrogen (N) and phosphorus (P) losses, via both surface runoff and subsurface drainage water, was monitored in an agricultural field in northern Sweden for 32 years. The objective was to determine losses of N and P in a long-term perspective in relation to meteorological factors and impacts of agricultural land-use, with the focus on relative contributions of surface runoff and subsurface drainage water to N and P losses. In order to collect surface runoff water, an embankment was installed on three sides of the field and the fourth side had an open ditch that drove runoff water to a measuring station. Subsurface water draining from the field was collected in a fishbone-shaped drainage system that terminated at the measuring station. In 50% of years (16/32), mean annual concentration of total-N was significantly higher in subsurface drainage water than in surface runoff water. An opposing trend was seen for total-P, with mean annual concentration being significantly higher in surface runoff water than in subsurface drainage water in all but three of the 32 years monitored. Years with a barley crop had higher total-N concentration in subsurface drainage water, but no difference in surface runoff, compared with years with ley. In contrast, years with barley had lower total-P concentration in surface runoff than years with ley, with no difference in total-P in subsurface drainage water. This article is protected by copyright. All rights reserved.