Table 1.

Definitions of variables and source.

Variable	Definition	Measurement unit	Data source
Nitrate	Annual average content of nitrate in groundwater per municipality	mg/l	Umweltbundesamt (2010b)
Precip	Average daily amount of precipitation per year per municipality	mm	ZAMG (Strauss et al., 2012)
Temp	Average daily maximum temperature per year per municipality	°C	ZAMG (Strauss et al., 2012)
vs	Average volume of stones in the topsoil per municipality	%	European digital soil map (Balkovic et al., 2007)
fwc	Average field water capacity at 33 kPa in the topsoil per municipality	cm3/cm3	European digital soil map (Balkovic et al., 2007)
NBal	Gross Nitrogen Balance per municipality	kg/ha	Own calculation according to OECD Handbook (2007)
Fert	Total amount of Fertilizer per municipality	kg/ha	Own calculation according to OECD Handbook (2007)
Withd	Total amount of nitrogen withdrawal per municipality	kg/ha	Own calculation according to OECD Handbook (2007)
Landuse_grassland	Proportion of grassland per municipality	%	CORINE Land Cover database 2006
Landuse_crops	Proportion of cropland per municipality	%	CORINE Land Cover database 2006
Landuse_buildings	Proportion of buildings per municipality	%	CORINE Land Cover database 2006
Landuse_forest	Proportion of forest per municipality	%	CORINE Land Cover database 2006
PropAL	Proportion of agricultural land per municipality	%	IACS database (1999–2008)
Landcover_oilseed & proteins	Proportion of oilseed and protein crops per municipality	%	IACS database (1999–2008)
Landcover_forage crops	Proportion of forage crops per municipality	%	IACS database (1999–2008)
Landcover_cereal & maize	Proportion of cereal and maize per municipality	%	IACS database (1999–2008)
Landcover_row crops & veg	Proportion of row crops and vegetables	%	IACS database (1999–2008)
Farming_system	Weighted indicator for organic/conventional cultivation per municipality	1 (org.)–2 (conv.)	IACS database (1999–2008)