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Table 3 Fe and Al oxides in soils collected across China

From: Organic phosphorus leaching risk from agricultural soils across China

Soils

TFe

(mg kg−1)

Tal

(mg kg−1)

WFe

(mg kg−1)

Wal

(mg kg−1)

Fefr

(mg kg−1)

Alfr

(mg kg−1)

Fear

(mg kg−1)

Alar

(mg kg−1)

Feco

(mg kg−1)

Alco

(mg kg−1)

Total soils (n = 63)

 Min

0.20

0.37

0.01

0.02

2.07

0.34

0.47

0.52

0.02

0.01

 Max

57.7

8.72

10.7

15.5

40.3

7.73

8.70

2.72

8.48

3.42

 Mean

24.8

3.73

1.10

1.36

11.8

2.07

3.36

1.51

1.11

0.69

 SD

10.1

2.32

2.10

2.84

8.63

1.68

1.65

0.50

1.58

0.79

Paddy soils (n = 21)

 Min

9.55

0.58

0.02

0.02

2.07

0.34

0.86

0.52

0.09

0.06

 Max

56.3

7.89

7.69

15.5

26.0

4.63

6.85

1.51

2.45

1.33

 Mean

27.1a

3.55b

1.57a

2.40a

10.4a

1.66b

3.30b

1.16b

0.97b

0.56b

 SD

9.26

2.47

2.56

4.34

6.92

1.31

1.43

0.27

0.67

0.36

Red soils (n = 11)

 Min

0.20

0.37

0.01

0.02

3.27

0.71

2.67

1.12

0.50

0.38

 Max

25.9

6.78

10.7

8.20

40.3

6.35

8.70

2.72

8.48

3.42

 Mean

15.9b

2.82b

1.13a

0.91a

11.2a

1.78ab

4.59a

1.90a

3.06a

1.73a

 SD

8.29

1.93

3.19

2.42

10.6

1.59

1.83

0.52

2.79

1.22

Chernozem (n = 13)

 Min

16.6

0.53

0.15

0.12

6.03

0.93

2.14

1.19

0.02

0.01

 Max

36.3

7.35

2.32

3.13

35.1

7.73

6.64

2.41

2.88

1.76

 Mean

26.9a

2.86b

0.83a

1.00a

14.5a

3.10a

4.01ab

1.85a

0.90b

0.68b

 SD

6.69

2.23

0.71

1.15

11.0

2.41

1.67

0.38

0.97

0.61

Other soils (n = 18)

 Min

1.68

2.33

0.01

0.03

4.70

0.70

0.47

0.54

0.03

0.02

 Max

57.7

8.72

5.58

3.08

32.7

5.16

3.89

2.29

0.73

0.52

 Mean

26.2a

5.12a

0.74a

0.67a

11.6a

1.95ab

2.21c

1.42b

0.22b

0.21c

 SD

11.7

1.91

1.27

0.87

7.36

1.24

0.94

0.47

0.17

0.17

  1. Different letters indicate significant difference (p < 0.05) between paddy soils, red soils, chernozem, and other soils
  2. n number of soil samples, SD standard deviation, TFe total Fe, TAl total Al, WFe water-soluble Fe, WAl water-soluble Al, Fefr free Fe oxides, Alfr free Al oxides, Fear amorphous Fe oxides, Alar amorphous Al oxides, Feco complexing Fe oxides, Alco complexing Al oxides