Simulation and areal interpolation by different methods of atrazine transport

Atrazine behaviour under field soil conditions is simulated by using a physically-based model (HYDRUS). Examined alluvial soils, located in a reclaimed agricultural area in northern Italy, are characterized by having a high potential hydrological vulnerability. As a prediction sample, computer outputs of maximum penetration depth and atrazine concentration in the upper soil layer are used as point data sets. Both isolinear and choropleth maps of related environmental risk of groundwater contamination by atrazine, through leaching or soil erosion, are constructed using different interpolation methods. Local methods (i.e. moving average, weighted moving averages, and ordinary block kriging) perform better than a global, quadratic trend surface method. Kriging provides the best predictor. To evaluate the associated uncertainty of spatial prediction, a simplified approach for mapping a specified conditional probability of the variable of interest is also shown.