Table 3 Performance of soil free iron content models based on correlated spectrum.

From: Estimation of soil free Iron content using spectral reflectance and machine learning algorithms

Spectral

Modeling

Training

Testing

Transform

Methods

R2

RMSE (g/kg)

RRMSE (%)

R2

RMSE (g/kg)

RRMSE (%)

Original

PLS

0.605

7.361

33.0

0.549

7.543

35.0

SVM

0.737

6.153

29.0

0.557

7.768

35.4

RF

0.883

4.308

19.6

0.335

9.558

43.5

DNN

0.748

5.929

26.2

0.654

6.841

31.2

FD

PLS

0.569

7.721

33.9

0.415

8.589

39.8

SVM

0.585

7.799

37.8

0.458

8.786

40.0

RF

0.893

4.759

21.5

0.147

10.825

49.3

DNN

0.607

7.554

33.4

0.623

7.742

35.3

SNV

PLS

0.471

8.509

38.4

0.434

8.463

38.2

SVM

0.546

7.899

37.1

0.478

8.426

38.4

RF

0.898

4.369

19.9

0.578

7.585

34.6

DNN

0.666

7.014

31.7

0.626

7.219

32.9

CR

PLS

0.694

6.472

28.8

0.636

6.776

31.4

SVM

0.702

6.461

30.8

0.636

7.010

31.9

RF

0.823

3.612

16.4

0.502

8.122

37.0

DNN

0.738

6.144

27.1

0.646

6.990

31.8