Mapping Soil Properties at a Regional Scale: Assessing Deterministic vs. Geostatistical Interpolation Methods at Different Soil Depths

To determine which interpolation technique is the most suitable for each case study an essential task a correct soil mapping, particularly in studies performed at regional scale. So, our main goal was to identify accurate method mapping 12 variables three different depth intervals: 0–5, 5–10 and >10 cm. For doing that, we have compared nine methods (deterministic geostatistical), drawing maps of Spanish region Extremadura (41,635 km2 size) from more than 400 sampling sites total (e.g., 500 pH 0–5 cm). We used coefficient determination (R2), mean error (ME) root square (RMSE) as statistical parameters assess accuracy method. The results indicated that varied depending on property study. In properties such clay, EBK (Empirical Bayesian Kriging) cm layer (R2 = 0.767 RMSE 3.318). However, depth, it IDW (Inverse Distance Weighted) with R2 values 0.689 5.131, respectively. other pH, CRS (Completely Regularized Spline) best 0.834 0.333), while predicting below 10 0.825 0.399). According findings, concluded necessary choose proper mapping.