Estimation of nitrogen and phosphorus losses to surface water and groundwater through the implementation of the SWAT model for Norwegian soils

Abstract

Scope and Background It is acknowledged that diffuse sources cause the most important nitrogen (N) and phosphorus (P) losses to the river system and substantially enrich the groundwater in nitrates. These losses arise primary from agricultural activities mainly fertilizer applications, and they are determined by soil attributes. In cold climates, winter conditions and freezing of soils may influence the infiltration capacity of the soil and thereby can have a serious effect on the partitioning of excess precipitation and subsequently on the soil and nutrient transportation. The purpose of this article is to investigate the behaviour of six widespread and different textured soil types, on nutrient (N, P) losses under cold climate conditions. The investigation was conducted in the Norwegian Vansjo-Hobolv catchment through the application of a physical model named Soil and Water Assessment Tool (SWAT), taking into consideration the additional aspect of freezing soils during winter, which distinguishes Scandinavian from other European soils.