In the Finnish conditions, annual N leaching from the experimental plots was not adequately estimated using the respective annual N balances, or supplementing the estimation with annual precipitation, total runoff, or drainage runoff (Salo and Turtola, 2006). Values averaged over the years improved the estimation when management included such environmentally risky managements as bare fallow or off-season application of cow slurry (Salo and Turtola, 2006). Calculated with the linear regression (Salo and Turtola, 2006), N leaching was 20-57 % of the averaged N balance