Table 4 Factor loadings based on correlations matrix and total variance explained by the principal components (OM.: added organic matter, PW.: pore water, Ex.: exchangeable ion)

Sensor EC

− 0.290

0.628

0.326

0.450

Sand

0.702

0.283

− 0.543

-0.163

Clay

− 0.377

− 0.262

0.708

0.294

Silt

− 0.777

-0.266

0.421

0.092

soil pH

0.456

0.351

− 0.061

− 0.365

soil EC

− 0.559

0.559

− 0.028

− 0.291

SOM

− 0.426

0.451

− 0.437

0.032

CEC

0.459

0.534

0.628

− 0.266

PW. pH

0.815

− 0.248

0.058

− 0.259

PW. EC

0.398

0.480

− 0.305

− 0.069

PW. NO₃⁻

− 0.683

0.066

− 0.005

− 0.355

PW. Ca

− 0.337

0.744

− 0.165

− 0.360

PW. K

− 0.077

0.568

− 0.428

0.657

PW. P

0.369

0.654

− 0.202

0.507

PW. S

− 0.740

0.325

− 0.178

− 0.478

Ex. Ca

0.582

0.440

0.495

− 0.391

Ex. K

− 0.637

0.359

− 0.316

0.264

Ex. Mg

0.038

0.404

0.808

0.108

Ex. Na

0.037

0.676

0.429

0.310

Ex. P

0.699

0.595

0.111

0.103

Ex. S

− 0.618

0.579

0.130

− 0.421

Variability (%)

28.307

23.223

15.517

11.319

Cumulative (%)

28.307

51.530

67.047

78.365