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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)