High-resolution imaging of a vineyard in south of France using ground-penetrating radar, electromagnetic induction and electrical resistivity tomography

Detailed knowledge of soil properties regulating soil water availability for the vines is of prime importance for optimal vineyard management. As soil characteristics may vary strongly over short distances, specific tools are required for efficient assessment and monitoring of soil water distribution and dynamics with fine spatial resolution. In that respect, ground-penetrating radar (GPR), electromagnetic induction (EMI) and electrical resistivity tomography (ERT) surveys were carried out in a vineyard in southern France in order to produce high-resolution maps of soil stratigraphy and to retrieve soil hydrogeophysical properties of the different soil layers. The results presented in this paper show large spatial variations in vineyard soil properties, which are in accordance with the distribution of the different soil types within the study area. This is particularly observable from EMI and ERT data, which show strong spatial correlation with large areas of comparable values delimited by well-defined discontinuities, revealing sharp variations of soil characteristics over short distances. These discontinuities almost systematically correspond to the limits of the vineyard plots, though areas of contrasting soil electrical conductivity values are also found within some plots. Furthermore, the patterns of soil electrical conductivity and resistivity are in good agreement with soil stratigraphy observed from GPR measurements. Finally, these results also highlighted anthropogenic soil compaction resulting from agricultural practices during too wet soil conditions as a likely explanation to vine vigor problems observed locally in the vineyard, which is corroborated by the observation of lower values of the normalized difference vegetation index (NDVI) for the vine in zones where soil compaction was evidenced by both geophysical measurements and soil profile description. (C) 2011 Elsevier B.V. All rights reserved.