Soil electrical conductivity obtained by contact or induction sensors has been used as a variable that correlates with soil characteristics of interest on spatial variability analysis. This work reports the experience done in a 19 ha no-till field aiming to correlate soil electrical conductivity (EC) measured by an induction sensor and soil chemical fertility properties, soil texture, altitude, humidity, soil fertility and corn and soybean yield between 2000 and 2002. Yield data was obtained using a yield monitor; EC and the other parameters were sampled based on a regular grid. Data were submitted to a spatial analysis generating maps for correlation analysis among the factors. EC sensor was limited on its operation, especially for not having a data logger, and requiring frequent calibrations. EC data were strongly spatially dependent but with inverse correlation between the two reading depths. Clay and water content resulted in positive correlations with EC in the shallow reading but at levels lower than expected.
precision agriculture; spatial variability; yield factors
