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Table 8 Summary effect estimates for meta-analyses of concentration data

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

Tillage comparisonSoil depth (cm)Summary effect estimate (g/kg)Standard errorz statisticp valueLower 95% confidence intervalUpper 95% confidence intervalNumber of studies
NT–HT0–152.0860.3446.073< 0.0011.4132.760102
15–30− 0.2980.286− 1.0390.299− 0.8590.26449
> 30− 0.3710.261− 1.4240.155− 0.8820.13431
NT–IT0–151.1790.3343.537< 0.0010.5261.83395
15–300.2730.2890.9440.345− 0.2930.83945
> 30− 0.1570.186− 0.8450.398− 0.5220.20820
IT–HT0–151.2290.2215.575< 0.0010.7971.66277
15–30− 0.8900.198− 4.539< 0.001− 1.288− 0.51142
> 30− 0.2610.209− 1.2500.211− 0.6710.14816
  1. NT no tillage, IT intermediate intensity tillage, HT high intensity tillage (see text for explanation)