Long-Term Effects of Different Fertilizer Management Practices on Soil Organic Carbon Pool in Smallholder Farms of the Huang– Huai–Hai Plains, China - Soil Management of Smallholder Agriculture - page 179

TABLE 7.5
Trend Line Regression Equations of Temporal Changes in SOC Pool for
Different Fertilizer Managements

Threshold

SOC Pool
(Mg ha −1 )

Treatments Region Trend Model Years

R 2

CF XinjiA y = 0.22 x + 17.44 R 2 = 0.56*** 20.00 21.80

XinjiB y = 0.08 x + 18.54 R 2 = 0.12 20.00 20.20

Xuzhou y = −0.09 x + 18.33 R 2 = 0.04 0.00 18.33

Changping y = −0.21 x + 23.46 R 2 = 0.31*** 0.00 23.46

ZhengzhouA y = −0.01 x + 22.48 R 2 = 0.00 0.00 22.48

ZhengzhouB y = 0.04 x + 20.20 R 2 = 0.00 8.00 20.53

HenshuiA y = 0.07 x + 18.23 R 2 = 0.17 21.00 19.70

HenshuiB y = −0.02 x + 20.58 R 2 = 0.02 0.00 20.58

O XinjiB y = 0.30 x + 18.84 R 2 = 0.82*** 20.00 24.94

Xuzhou y = −0.25 x 2 + 3.01 x + 18.26 R 2 = 0.94** 6.08 27.41

ZhengzhouA y = 0.10 x + 21.37 R 2 = 0.10 18.00 23.11

HenshuiA y = −0.06 x + 18.89 R 2 = 0.12 0.00 18.89

HenshuiB y = 0.07 x + 20.75 R 2 = 0.12 23.00 22.38

UF XinjiA y = 0.19 x + 17.10 R 2 = 0.60*** 20.00 20.82

XinjiB y = 0.036 x + 17.43 R 2 = 0.07 20.00 18.14

Xuzhou y = −0.17 x + 18.64 R 2 = 0.21 0.00 18.64

Changping y = −0.20 x + 22.05 R 2 = 0.32** 0.00 22.05

ZhengzhouA y = −0.07 x + 22.33 R 2 = 0.19 0.00 22.33

ZhengzhouB y = −0.09 x + 19.92 R 2 = 0.04 0.00 19.92

HenshuiA y = 0.02 x + 18.35 R 2 = 0.02 21.00 18.77

CFO XinjiA y = −0.06 x 2 + 2.42 x + 16.72 R 2 = 0.59** 21.00 42.09

XinjiB y = −0.0037 x 2 + 0.31 x + 19.94 R 2 = 0.60** 41.88 26.42

Xuzhou y = −0.06 x 2 + 1.74 x + 20.63 R 2 = 0.92*** 15.68 34.24

Changping y = −0.01 x 2 + 0.05 x + 23.15 R 2 = 0.02 2.90 23.23

ZhengzhouA y = 0.09 x + 22.24 R 2 = 0.18* 18.00 23.91

ZhengzhouB y = −0.03 x 2 + 0.48 x + 21.75 R 2 = 0.29* 8.64 23.82

HenshuiA y = 0.24 x + 18.45 R 2 = 0.42*** 21.00 23.57

HenshuiB y = 0.10 x + 20.75 R 2 = 0.19* 23.00 22.98

UFO XinjiA y = −0.05 x 2 + 2.32 x + 16.18 R 2 = 0.64** 22.95 42.83

XinjiB y = 0.36 x + 17.98 R 2 = 0.82*** 20.00 25.15

Xuzhou y = −0.05 x 2 + 1.51 x + 21.00 R 2 = 0.88*** 15.75 32.91

Changping y = −0.06 x + 22.23 R 2 = 0.04 0.00 22.28

ZhengzhouA y = 0.08 x + 21.94 R 2 = 0.13 18.00 23.39

HenshuiA y = 0.20 x + 18.50 R 2 = 0.14*** 21.00 22.75

( continued )