Dataset - European multi-trial data set on carbon and nitrogen isotope ratios of winter wheat spanning 170 years

Dataset - European multi-trial data set on carbon and nitrogen isotope ratios of winter wheat spanning 170 years Overview This dataset provides a harmonized collection of stable carbon (d13C) and nitrogen (d15N) isotopic compositions from winter wheat. It encompasses ten long-term and short-term field trials across Switzerland, France, Germany, Denmark, and the United Kingdom, spanning over 170 years of agricultural history. The data is designed for investigating long-term (Genotype x) Environment x Management interactions, benchmarking crop models, and conducting comparative analyses of carbon and nitrogen dynamics in European agroecosystems. Dataset Structure The dataset consists of two primary CSV files linked by a Unique Identifier (UID). Missing values are encoded as NA. 1. Main Data File (winter_wheat_isotopes_management.csv) This file contains one row per sample, including site metadata, management treatments, nitrogen inputs, crop variety, sampling dates, and C and N isotopic composition. Variable Name Unit Description location - Name of the site location trial_ID - Abbreviation of the trial trial_name - Name of the experimental trial year - Harvest year of this sample UID - Unique sample identifier material - Either grain or straw to define the material of the sample id_local - Name of the treatment in the naming convention of the original trial rep - Replication number treatment_level - Given name for each N application to compare within and between experiments N_tot_input kg N ha-1 Total applied N for the corresponding cropping season N_min kg N ha-1 Applied mineral N for the corresponding cropping season N_org kg N ha-1 Applied organic N for the corresponding cropping season lat decimal degrees Latitude of the trial lon decimal degrees Longitude of the trial elevation m a.s.l. Elevation of the trial sowing_date YYYYMMDD Date when sowing took place harvest_date YYYYMMDD Date when harvest took place variety - Name of the variety cultivated previous_crop - Name of the crop cultivated in the previous to the sample d13C permille Carbon isotopic composition (delta 13C) d15N permille Nitrogen isotopic composition (delta 15N) C_content % Carbon concentration of the sample N_content % Nitrogen concentration of the sample C_N_ratio - Ratio of carbon to nitrogen content responsible_person - Contact to the PI of this data point comments - Additional comments if required 2. Yield Data File (winter_wheat_yield.csv) Contains grain and straw yield information associated with the samples in the main dataset. Variable Name Unit Description location - Name of the site location trial_ID - Abbreviation of the location trial_name - Name of the experimental trial year - Harvest year of this sample UID - Unique sample identifier material - Either grain or straw to define the material of the sample yield_t_ha dry matter t ha-1 Grain or straw yield responsible_person - Contact to the PI of this data point reference_to_cite - Publication to be cited if this data point is used 3. Askov Detailed Info (Askov_detailed_sowing_harvest_variety_info.csv) This auxiliary file provides high-resolution metadata specifically for the Askov long-term experiment, including field-specific identifiers and variety details. This is included since the samples are bulked over 4 year periods. Variable Name Unit Description location - Name of the site location (Askov) location_ID - Abbreviation for the location (AS) trial_name - Full name of the experimental trial year - Harvest year field - Specific field or plot identifier (e.g., B2, B3, B4) sowing_date YYYYMMDD Specific date when sowing took place harvest_date YYYYMMDD Specific date when harvest took place variety - Name of the winter wheat variety cultivated responsible_person - Name and email of the Principal Investigator for this site Technical Validation Technical validation confirms that management records and isotope measurements are agronomically and physiologically plausible and internally consistent across sites and years. Please cite this dataset and corresponding publication if you use the data