“…The data that presented spatial dependence, i.e., did not present a pure nugget effect (PNE) in the semivariogram analysis, were interpolated by ordinary kriging. Then, spatial distribution ECa maps were generated with three classes of values (high, moderate, and low) determined by the Jenks optimization method, which minimizes the differences between intraclass values and maximizes the differences between classes (Fraile et al, 2016). The calculation of the experimental semivariograms, the fittingof the respective theoretical models, cross-validation, and the interpolation of the data were performed using the GS + 7.0 software and the RMSE calculation was conducted with the R 3.3.3 software (R Core Team, 2017).…”