Differentiating Soil Types Using Apparent Electrical Conductivity Survey in the Southeastern Cordoba, Argentina.

Variable rate technology enables management of individual soil types within fields. Correct soil type classification of soils in the Cordoba province is currently impractical and expensive using maps of 1:50000 scales, yet variable rate fertilizer application based on soil type can be highly effective. The objective of this study was to determine if apparent electric conductivity (ECa) using global positioning system technology can provide a useful alternative to detailed soil mapping. The site contained two unit mapping, EAo2 -composed by Aromos series (60%) (coarse-loamy,mixed, thermic, Typic Calciacuoll), (30%) (Medanitos series (coarse-loamy,mixed, thermic, Typic Natralboll), (10%) Canals series (coarse-loamy,mixed, thermic, Entic Haplustoll),and Cn, -composed by Canals series (100%). A survey with the Veris 3100 soil sensor provided 4207 measurements of the ECa within the studied area (39 ha). Soil properties and ECa were analyzed using ANOVA. The ANOVA showed that ECa measurements successfully delimited homogeneous soil zones. High ECa zones were dominated by Aromos and Medanitos series, low ECa zones were dominated by Canals series and medium ECa zones were between both series. These differences are reflected in the saline content and soil texture classifications for these soil ECa zones. Soil survey maps are useful for identifying general soil types in a region but are not precise enough to allow establishment of management zones for precision agricultural applications. An alternative to soil survey maps is the utilization of soil ECa maps to establish main soil types within a field and delineate management zones with much finer detail, therefore allowing the implementation of variable rate technology.