“…Contamination of shallow groundwater (<30 m bgl) with NO 3 -N has been documented in a large number of studies (C. D. A. McLay et al, 2001;Harter et al, 2002;Bohlke et al, 2007;Babiker et al, 2004). To relate different forms of landuse to different shallow groundwater NO 3 -N concentrations spatially, a variety of statistical techniques, such as multivariate cluster analysis (Hussain et al, 2008;Ismail and Ramadan, 1995;Yidana et al, 2008), Tobit and logistic regression using mean nutrient data (Gardner and Vogel, 2005;Kaown et al, 2007), weights of evidence modelling techniques (Masetti et al, 2008), and ordinary kriging methods (Hu et al, 2005), have been used.…”