Apparent soil electrical conductivity in two different soil types

Resumo

Mapping the apparent soil electrical conductivity (ECa) has become important for the characterization of the
soil variability in precision agriculture systems. Could the ECa be used to locate the soil sampling points for mapping the
chemical and physical soil attributes? The objective of this work was to examine the relations between ECa and soil attributes
in two fields presenting different soil textures. In each field, 50 sampling points were chosen using a path that presented a high
variability of ECa obtained from a preliminary ECa map. At each sampling point, the ECa was measured in soil depths of 0-20, 0-
40 and 0-60 cm. In addition, at each point, soil samples were collected for the determination of physical and chemical attributes
in the laboratory. The ECa data obtained for different soil depths was very similar. A large number of significant correlations
between ECa and the soil attributes were found. In the sandy clay loam texture field there was no correlation between ECa and
organic matter or between ECa and soil clay and sand content. However, a significant positive correlation was shown for the
remaining phosphorus. In the sandy loam texture field the ECa had a significant positive correlation with clay content and a
significant negative correlation with sand content. The results suggest that the mapping of apparent soil electrical conductivity
does not replace traditional soil sampling, however, it can be used as information to delimit regions in a field that have similar
soil attributes.