Integrated geophysical techniques for sustainable management of water resource. A case study of local dry bean versus commercial common bean cultivars

This paper deals with the combined use of non-invasive technologies for a reliable and ready measures of soil physical parameters. In particular, time domain reflectometry (TDR) was deployed for soil moisture estimation in combination with geophysical investigations as electrical resistivity tomography (ERT) and ground penetrating radar (GPR). The investigation regarded two cultivars of dry bean (Phaseolus vulgaris L.), a dry bean landrace and a common bean. The irrigation of these cultivars have been carried out by drip emitters placed on the bean rows, with different irrigation regimes based on crop evapotranspiration (ETc) demand calculated from the analysis of weather data. Geophysical surveys, basesd on ERT and GPR, were performed during the growth season along transects longitudinal and parallel to the bean rows with the aim to obtain soil images for the identification and characterization of crop roots locations. Data analysis of variance indicated that a reduction in the total irrigation amount of 50% of Etc demand ensures good conditions of soil moisture and does not determine significantly decreased production in the local bean genotype, probably because of its lower sensitivity to water stress. This confirms that the choice of autochthonous varieties well adapted to the local environment, could be a winning choice forthe purpose of sustainable management of irrigation water.