Table 1 Prediction performance of test data.

Anhui (16)

Adjusted R2_test

0.782

0.718

0.964

/

0.661

0.955

MSE_test

15731

20275

2565

/

24420

3224

Fujian (9)

Adjusted R2_test

0.137

0.847

0.354

/

0.617

0.947

MSE_test

83706

14864

63684

/

37110

5105

Gansu (14)

Adjusted R2_test

0.804

0.898

0.466

−0.194

0.965

0.870

MSE_test

20127

10418

54718

122294

3599

13330

Guangdong (21)

Adjusted R2_test

0.467

0.824

0.484

0.467

0.924

0.960

MSE_test

28108

9297

27211

28107.700

3987

2087

Guangxi (14)

Adjusted R2_test

0.952

0.981

0.173

0.198

0.985

0.984

MSE_test

22671

9129

392541

380296

6923

7647

Guizhou (9)

Adjusted R2_test

−0.100

−0.077

−0.093

−0.251

−0.072

−0.059

MSE_test

42835

41936

42562

48716

41757

41249

Hebei (11)

Adjusted R2_test

0.942

0.969

0.746

0.055

0.987

0.962

MSE_test

675070

359826

2942654

10967061

152356

443062

Henan (14)

Adjusted R2_test

0.836

0.919

0.251

0.429

0.942

0.918

MSE_test

60971

30046

278623

212262

216034

30670

Heilongjiang (13)

Adjusted R2_test

0.172

0.929

0.402

−0.560

0.940

0.955

MSE_test

75787

6518

54714

142681

5447

4112

Hubei (13)

Adjusted R2_test

0.649

0.866

0.659

0.035

0.858

0.955

MSE_test

71609

27251

69444

196736

28991

9228

Hunan (14)

Adjusted R2_test

0.659

0.759

0.740

0.012

0.898

0.933

MSE_test

28260

20007

21590

81976

8439

5522

Jilin (9)

Adjusted R2_test

/

0.882

/

0.154

0.913

0.907

MSE_test

/

13995

/

100431

10355

10990

Jiangsu (13)

Adjusted R2_test

/

0.960

/

−0.006

0.987

0.991

MSE_test

/

15889

/

400932

5208

3394

Jiangxi (11)

Adjusted R2_test

0.975

0.993

/

0.811

0.994

0.992

MSE_test

48807

13879

/

375865.500

11364

15768

Liaoning (14)

Adjusted R2_test

/

0.633

−0.143

0.000

0.892

0.841

MSE_test

/

558383

1736208

1519475

163993

241168

Inner Mongolia (12)

Adjusted R2_test

0.502

0.833

0.067

0.414

0.801

0.818

MSE_test

1376167

462105

2576858

1619270

549723

503258

Ningxia (5)

Adjusted R2_test

0.814

0.963

0.499

−0.695

0.958

0.945

MSE_test

16173

3233

43631

147584

3630

4773

Shandong (16)

Adjusted R2_test

/

0.939

/

0.063

0.974

0.975

MSE_test

/

36989

/

564314

15594

15235

Shanxi (11)

Adjusted R2_test

0.511

0.674

0.335

−0.136

0.886

0.817

MSE_test

308339

205553

418711

715351

71612

115227

Shaanxi (10)

Adjusted R2_test

0.936

0.527

0.807

0.224

0.985

0.954

MSE_test

38179

282946

115464

464846

9242

27301

Sichuang (21)

Adjusted R2_test

0.948

0.951

0.864

−0.013

0.966

0.915

MSE_test

21117

19727

55043

409693

13615

34183

Xinjiang (14)

Adjusted R2_test

0.829

0.955

0.586

0.298

0.858

0.944

MSE_test

65959

17238

159222

270054

54475

21478

Yunnan (16)

Adjusted R2_test

0.092

0.792

0.570

0.368

0.923

0.944

MSE_test

418064

95843

198035

291096

35414

25995

Zhejiang (11)

Adjusted R2_test

0.895

0.973

0.831

0.555

0.982

0.964

MSE_test

6992

1805

11254

29613

1164

2412