Using the ARP-03 for high-resolution mapping of calcic horizons

The aim of this work is to present a fast and cheapmethod for high-resolutionmapping of calcic horizons in vineyardsbased on geoelectrical proximal sensing. The study area, 45 ha locatedin southern Sicily (Italy), was characterized by an old, partiallydismantled marine terrace and soils with a calcic horizon atdifferent depths. The geoelectrical investigation consisted of a surveyof the soil electrical resistivity recorded with the AutomaticResistivity Profiling-03 sensor. The electrical resistivity values atthree pseudo-depths, 0-50, 0-100 and 0-170 cm, were spatializedby means of ordinary kriging. A principal component analysis ofthe three electrical resistivity maps was carried out. During the survey,18 boreholes, located at different electrical resistivity values,were made for soil description and sampling. The depth to thecalcic horizon showed a strong correlation with electrical resistivity.The regression model between calcic horizon and the principalcomponent analysis factors with the highest correlation coefficientswas selected to spatialise the calcic horizon values. AnNormalized Difference Vegetation Index map was used to validatethe calcic horizon map in terms of crop response to different soilrooting depths. The strengths of this method are the quick, non-invasivekind of survey, the relevance for vine vigour, and the highspatial resolution of the final map.