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

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

Variable	Value	Score
Spatial (true) replication	2 replicates	0
	3–4 replicates	1
	> 4 replicates	2
Temporal replication	≤ 3 replicates	0
	4–6 replicates	1
	> 6 replicates	2
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)	10–19	0
	20–29	1
	≥ 30	2
Soil sampling depth	Shallow (maximum depth ≤ 15 cm) single or multiple sampling	0
	Plough layer (maximum depth 15–25 cm) single or multiple sampling, or deep (maximum depth > 25 cm) single sampling	1
	Multiple deep sampling (maximum depth > 25 cm)	2

Italics text indicates the domains used for critical appraisal in the full systematic review described herein

ISSN: 2047-2382