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Table 9 Summary effect estimates for meta-analyses of stocks data

From: How does tillage intensity affect soil organic carbon? A systematic review

Tillage comparison

Soil depth (cm)

Summary effect estimate (Mg/ha)

Standard error

z statistic

p value

Lower 95% confidence interval

Upper 95% confidence interval

Number of studies

NT–HT

Upper layer

4.606

1.954

2.357

0.018

0.776

8.435

29

 

Full profile

1.646

3.409

0.483

0.629

− 5.035

8.327

14

NT–IT

Upper layer

3.852

1.644

2.343

0.019

0.630

7.075

32

 

Full profile

0.831

2.711

0.306

0.759

− 4.483

6.144

13

IT–HT

Upper layer

1.724

0.952

1.811

0.070

− 0.142

3.589

29

 

Full profile

1.883

2.529

0.745

0.457

− 3.074

6.840

10

  1. ‘Upper layer’ corresponds to measurements between 0 and up to 30 cm depth, whilst ‘full profile’ corresponds to measurements taken between 0 and between 30 and 150 cm depth
  2. NT no tillage, IT intermediate intensity tillage, HT high intensity tillage (see text for explanation)