Spatial representations of soil attributes with low resolution can lead to gross errors of recommendation and compromise the efficiency of soil corrections and consequently the grain yield. However, obtaining the spatial variability of soil attributes with high resolution by soil sampling is not recommended because of its large time spent and high cost of laboratory analysis what makes difficult their large-scale application. This way, the on-the-go soil sensing has been used in precision agriculture (PA), but, studies are still incipient in Red Oxisols in Southern Brazil. The aims of this study were to examine relationships between soil electrical conductivity apparent (ECa), measured through the on-the-go sensor, with soil properties and corn yield, besides mapping with high resolution the main acidity attributes of Southern Brazil dystrophic Red Oxisol. The mobile soil sensing was performed in two fields with 42 and 39 ha located in northwest of Rio Grande do Sul State, Brazil using the sensor VERIS 3100. It has been calibrated to operate in depths of 0-30 cm and 0-90 cm. The soil sampling was performed using an auger at 0-15 cm depth. The yield grain was obtained by used of yield sensor installed on the combine. The ECa was related with corn yield, cation exchange capacity, sum of bases, and calcium and magnesium content, in both fields, having yet relationship with soil acidity properties at the low chemical quality field. The ECa was an efficient indirect method of getting high-resolution soil acidity mapping in a dystrophic Red Oxisol. Once, the ECa sensing on-the-go calibrated to the soil type and crop investigated, and being combined with site-specific soil sampling it becomes an effective strategy for the spatial high-resolution chemical attributes allowing adequate prescription variable rate correctives and soil conditioners.