Soil Spatial variability factors influencing nitrate contamination in groundwater in Molise (southern Italy)

Spatial variability was used to analyze soil factors influencing the occurrence of high nitrate concentrations in groundwater resources in the region of Molise (southern Italy). The proposed methodology applied in two agricultural areas combines measurements of nitrate concentrations, carried out by means of a monitoring network of 69 soils, with spatial distribution data. These variables describe both soil potential sources of nitrate and the relative possibility with which it may migrate towards groundwater, and include soil parameter such as nitrogen fertilizer loading and irrigation systems. Different methods with different information levels were compared to assess the groundwater nitrate contamination risk: the IPNOA index and direct NO3 - concentration soil measurements. The results of this research could be useful for analysing the spatial variability of some soil properties and their influence on the presence of nitrate in groundwater. The latter aspect could represent an important aid for sound land use management to preserve groundwater quality.