Table 1 Proposed coding and meta-data extraction schema
Variable | Description | Meta-data or coding |
|---|---|---|
Study ID | Unique study identifier linked to article ID | Meta-data |
Citation | Full citation of the article containing the study | Meta-data |
Email address | Main author email address provided within the publication if present | Meta-data |
Study country | Coding | |
Latitude | Decimal degree | Meta-data |
Longitude | Decimal degree | Meta-data |
Köppen-Geiger climate zone | Climate zones | Coding |
Soil texture classification | USDA texture classifications | Coding |
Soil comments | Description of soil texture, including clay, silt, sand percentages, alternative soil classification names, etc. | Meta-data |
Intervention start | Year during which the intervention began | Meta-data |
Intervention end | Year during which the intervention ended or when the study was completed | Meta-data |
Intervention duration | Length of the study period in years | Meta-data |
Intervention type | Amendments, crop rotation, fertiliser, tillage, other, multiple | Coding |
Number of different treatments | Total number of farming practices investigated and reported | Meta-data |
Different treatments detail | Description of the treatments investigated and reported | Meta-data |
Study design | Before-after-control-intervention, before-after, comparator-intervention | Coding |
Experimental design | Randomised control trial, split/strip plot, Latin square, paired design, purposive | Coding |
Spatial replication | Number of true spatial replicates at the intervention level, i.e. if the intervention was applied at the field scale replication would need to be at the field scale also | Meta-data |
Temporal replication | Multiple time points measured after intervention (yes/no) | Coding |
Measured outcome | N2O, CO2, CH4 | Coding |
Quantification method | Description of GHG measurement method, e.g. infrared spectrometer | Meta-data |
Sampling equipment | Static chamber, dynamic chambers, eddy flux covariance tower | Coding |
Sampling equipment description | Description of tower set-up, including tower height, gap filling, etc. Description of mitigation measures for chamber equipment, e.g. presence of boardwalks, permanent collars, pressure equalisers, radiators, etc. | Meta-data |