This readme file was generated on 2025-09-09 by Sabina Braun and provides a list and description of each file included in the dataset.

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DATASET GENERAL INFORMATION
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Title of dataset: SLU long-term field experiments: Soil organic matter in a cereal-only cropping system (R3-0020), crop and soil data from 1971 and onwards
Creator(s)/Primary investigator(s): Swedish University of Agricultural Sciences
Persistent identifier of dataset: 
Related publication for description of project, methods etc: Mattsson, L., 2010, Soil Organic C Development in Cereal and Ley Systems. Data from 20 years old Swedish field experiments
https://doi.org/10.1080/03650340214164 [In English]
Missing data delimiter: NA

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FILE OVERVIEW
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R30020_data.tsv
Tab-delimited numeric data corresponding to soil and crop properties from experiment. 
Relationship between files: R30020_data column names LTE, ID, year, crop, plotID, treatment_code, straw_management, N_added, component, variable, value, and unit defined in R30020_metadata.tsv; components defined in R30020component_descriptions.tsv; variable defined in R30020variable_descriptions.tsv; units defined in R30020unit_descriptions.tsv; location defined in R30020location_description.tsv

R30020_metadata.tsv
Tab-delimited definitions of column names in R30020_data.tsv

R30020component_description.tsv
Tab-delimited definitions of component column in R30020_data.tsv


R30020variable_description.tsv
Tab-delimited definitions of variable column in R30020_data.tsv


R30020unit_description.tsv
Tab-delimited definitions of unit column in R30020_data.tsv


R30020location_description.tsv
Tab-delimited definitions of location column in R30020_data.tsv


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DATA-SPECIFIC INFORMATION FOR R30020_data.tsv
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License: CC0 1.0 

Number of columns: 13

Number of rows: 25695

Explanation of missing/empty data: data outside of feasible values are denoted by NA. 

Variable list:

Column	Description
LTE	The SLU code for the experimental series
ID	THe SLU code for the specific experiemntal site
plotID	Denotes the specific plot (parcell) number. X is used when data was collected from a composite sample from all plots with the same treatment.
treatment_code	Denotes treatment code, the combination of factors for the plot
straw_management	Denotes if straw is kept in the field or removed 
N_added	Denotes four levels of yearly N addition
component	The component that has been analysed or observed
year	The year the sample or observation was taken
crop	The crop grown during the growing season  
variable	The measured variable
value	The value of the variable
unit	The unit for the measured variable

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DATA-SPECIFIC INFORMATION FOR R30020component_description.tsv
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License: CC0 1.0 

Number of columns/variables: 2

Number of rows/cases: 5

Variable list:  
	component: name of component as in component column of R30020_data.tsv
	description: definition of component

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DATA-SPECIFIC INFORMATION FOR R30020variable_description.tsv
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License: CC0 1.0 

Number of columns/variables: 3

Number of rows/cases: 22

Variable list:  
	variable: name of variable as in R30020_data.tsv
	description: definition of variable
	unit: definition of variable unit

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DATA-SPECIFIC INFORMATION FOR R30020unit_description.tsv
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License: CC0 1.0 

Number of columns/variables: 3

Number of rows/cases: 8

Variable list:  
	unit: name of unit as in R30020_data.tsv
	description: definition of unit
	note: comment about unit

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DATA-SPECIFIC INFORMATION FOR R30020location_description.tsv
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License: CC0 1.0 

Number of columns/variables: 4

Number of rows/cases: 5

LTE		The SLU code for the experimental serie
ID		The SLU code for the specific experimental site
location	The name of the experimental site
Description	Description of the sites location
