Figure 1. a) Location of the two study watersheds and land use in these two watersheds in 2008; b) Field allocation number and BMPs implemented in the Steppler watershed since 2005.

Madill / Control watershed Steppler / Treatment watershed Figure 2. Share of different forms of P and N in snowmelt and rainfall events in the total N and P exports, respectively, for the whole study period (1999 – 2008) at the Madill and Steppler watershed.

b) TN export (Ln(g ha-1)), all runoff events a) TP export (Ln(g ha-1)), all runoff events Steppler / Treatment watershed value (Y) c) TP FWMC (Ln(mg L-1)), all runoff events d) TN FWMC (Ln(mg L-1)), all runoff events Madill / Control watershed value (X) Pre-period (calibration) Pre-period regression line Post-period (BMP implementation) Post-period regression line Figure 3. Simple regression analyses of TP and TN exports and Flow-Weighted-Mean-Concentrations (FWMCs) showing the effects of BMP implementation without accounting for the effects of hydrology variations.

a) N input, all fields b) P input, all fields c) N input, annual cropped fields d) P input, annual cropped fields e) N removal, all fields f) P removal, all fields g) N removal, annual cropped fields h) P removal, annual cropped fields i) N budget, all fields j) P budget, all fields k) N budget, annual cropped fields l) P budget, annual cropped fields Pre period Post period Madill Steppler Kg ha-1 yr-1 +7NS -26† +0NS -5** +14NS -16NS +4NS -4* +12NS -20NS +2NS +1NS -2NS -14NS -0NS -4NS -45* -1NS -6** +16NS -12NS +3NS -4† Figure 4. N and P input, removal and budget estimated from land use survey data for the Madill and Steppler watershed.