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Table 2 List of variables to be extracted from the papers for the systematic review

From: Are population abundances and biomasses of soil invertebrates changed by Bt crops compared with conventional crops? A systematic review protocol

Variable name Definition Type
Georeference, longitude GPS coordinate WGS 84 decimal format decimal
Georeference, latitude GPS coordinate WGS 84 decimal format decimal
Location Location of the experimental site characters
Crop Name of the crop characters
GM Event Name of the GM event characters
Treatment property Type of Bt toxin or comparator characters
Gene stacking Information about stacked event (0 - no, 1- yes), name of the stacked gene vector {Binary integer, characters}
Variety The commercial name of the variety characters
Comparator properties Information about the used comparator in relation with the Bt variety - isogenic or other. characters
Insecticide treatment Information about insecticide treatment (0 - no, 1- yes), the product name, active substance, amount, number, time and method for application. vector {Binary integer, characters, characters}
Experimental design RBC = Randomized complete blocks; CR = Completely randomized; Multi location = ML characters
Plot size Calculation of the plot size (in square meters) real number
Plots number Number of plots per treatment real number
Cropping system Conventional; Reduced tillage; Conservation tillage etc. characters
Crop rotation Information about the history of the experimental field characters
Tillage date Date since last tillage event, including ploughing, harrowing, rotovation etc. date
Date of cropping system establishment Date when the Bt crop was planted for first time date
Seeding date Date of seeding within each growing season date
Sampling date Date when the sampling was performed date
Order Name of the taxonomic order of the soil invertebrates characters
Family Name of the taxonomic family of the soil invertebrates characters
Species Name of the taxonomic species of the soil invertebrates characters
Stage of development Stage of development of the soil invertebrates characters
Sample type e.g. litterbags, bulk soil, rhizosphere characters
Sample depth Depth in the soil where the sample was taken real number
Sample amount Amount of soil in one sample real number
Sampling location Location from which the samples are take, e.g. between rows, within rows, distance from roots characters
Extraction method Used technique for extraction of soil invertebrates form the sample characters
Sample size Sample size as reported by the author real number
Measurement endpoint Type of measured endpoint, e.g. abundance, biomass characters
Unit Unit in which the measurement endpoint is presented characters
Value Value of the measured endpoint real number
Variability measure STD; SEM; CLM; Variance characters
Quantity Quantified variability real number
Soil type Soil type according to WRB classification characters
Other fixed and random effects E.g. fertilization, fungicide use, additional factors and effects of the experimental design characters
Data origin Table or figure from which the data originates characters
Data extraction How data was extracted, e.g. as exact number from tables or scaled numbers from graphs characters
Statistical analysis Description of the statistical methods for analysis of variance characters
Reference Bibliographic reference code as found in the GRACE CADIMA database (Central Access Database for Impact Assessment of Crop Genetic Improvement Technologies) characters
Source of funding Description of the funding source of the study characters
Authors affiliation Type of institution to which the first author belongs characters
Comments Any other information which may be relevant characters
Keywords Keywords for finding the reference in a systematic review - {list of keywords} characters