Spatial variability of apparent electrical conductivity and physicochemical attributes of the soil

The apparent electrical conductivity has been an attribute widely used in studies of spatial variability, due to its high correlation with other soil attributes and because it is an attribute that represents the variability of an area in a quick, easy and low-cost way. The objective of this study was to evaluate the relationship between the spatial variability of apparent electrical conductivity with physicochemical attributes of an Eutrophic Red Oxisol located in Maracaju, state of Mato Grosso do Sul, Brazil, for determining specific soil management zones. We analyzed apparent electrical conductivity attributes (ECa 2, 7 and 15 kHz), contents of potassium, cation exchange capacity, clay, base saturation and organic matter content. ECa was measured with the Profiler EMP-400 crossing the entire area in 0.45 m spaced lines. Soil samples were collected in the 0.000.20 m layer, with a total of 216 samples in an area of 70 ha. Statistical and geostatistical analyses were performed by SAS and GS+ software. The apparent electrical conductivity (ECa) was presented as an important tool to identify specific management zones showing data variability between low and medium zones. The attributes that had higher correlation with apparent electrical conductivity were potassium and clay