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Table 1 Critical appraisal criteria for five domains used in the systematic map by Haddaway et al. [33]

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

Spatial (true) replication 2 replicates 0
3–4 replicates 1
> 4 replicates 2
Temporal replication≤ 3 replicates0
4–6 replicates1
> 6 replicates2
Treatment allocation (as described for the full experimental design) Purposive (selective) 0
Split-/strip-plot/latin square/blocked/randomised/exhaustive 2
Duration of experiment (years)10–190
≥ 302
Soil sampling depthShallow (maximum depth ≤ 15 cm) single or multiple sampling0
Plough layer (maximum depth 15–25 cm) single or multiple sampling, or deep (maximum depth > 25 cm) single sampling1
Multiple deep sampling (maximum depth > 25 cm)2
  1. Italics text indicates the domains used for critical appraisal in the full systematic review described herein