Prediction of Soil Organic Carbon for Ethiopian Highlands Using Soil Spectroscopy
Table 2
Statistical summary of the samples analyzed for SOC content (%) for calibration, validation, and test sample sets.
Study sites
Number of samples
Min.
Max.
Med.
Mean
SDV
1st quartile
3rd quartile
Anjeni
Total
302
0.20
13.68
1.53
1.67
1.34
0.90
2.15
Calibration
145
0.20
13.68
1.39
1.54
1.36
0.84
1.94
Validation
96
0.21
9.90
1.55
1.70
1.27
0.92
2.22
Test
61
0.27
9.74
1.76
1.93
1.40
1.08
2.39
Bale
Total
74
1.23
7.50
3.14
3.35
1.49
2.26
4.22
Calibration
59
1.23
7.20
3.08
3.25
1.41
2.20
4.22
Test
15
1.84
7.5
3.36
3.78
1.81
2.56
4.47
Basketo
Total
102
0.28
8.05
2.18
2.30
1.60
0.94
2.77
Calibration
81
0.28
8.05
2.23
2.36
1.69
0.89
2.81
Test
21
0.39
5.6
2.18
2.13
1.23
1.52
2.4
Benishangul
Total
78
0.10
5.46
0.70
1.19
0.98
0.49
1.80
Calibration
64
0.10
5.46
0.72
1.19
1.01
0.44
1.73
Test
14
0.20
2.87
0.67
1.18
0.90
0.53
1.92
Kersa
Total
171
0.11
6.07
1.69
1.86
1.02
1.23
2.22
Calibration
135
0.11
6.07
1.77
1.91
1.05
1.24
2.36
Test
36
0.20
4.42
1.63
1.70
0.89
1.20
2.05
Kolatembien
Total
65
0.28
4.59
0.83
1.10
0.86
0.53
1.29
Calibration
51
0.28
4.59
0.81
1.05
0.85
0.48
1.21
Test
14
0.46
3.90
1.09
1.29
0.93
0.61
1.51
Maybar
Total
144
0.19
7.58
1.56
1.97
1.33
1.14
2.40
Calibration
115
0.19
7.58
1.54
1.99
1.42
1.09
2.34
Test
29
0.68
4.27
1.71
1.89
0.93
1.35
2.40
Megech
Total
147
0.16
2.54
0.88
0.92
0.38
0.74
1.11
Calibration
118
0.16
2.54
0.89
0.93
0.39
0.73
1.11
Test
29
0.32
1.44
0.84
0.87
0.29
0.78
1.02
Wondogenet
Total
71
1.23
8.29
3.1
3.37
1.38
2.34
4.21
Calibration
57
1.23
8.29
3.28
3.36
1.39
2.44
4.02
Test
14
1.56
6.16
2.96
3.36
1.43
2.34
4.30
SDV: the standard deviation, Min: minimum, Max: maximum, Med: median. All splits of the sample sets given in Table 2 have been tested for statistical conformity. For all splits, the test results confirmed the null hypothesis which is assuming homogeneity of the parameters tested.
