Cite the software
Maintainer and author: Mohammad Reza Eini. Use citation("yieldlag") in R.
Eini, M. R. (2026). YieldLag: Seasonal Climate Responses and Regional Crop Yield Modelling. R package version 0.3.0. GitHub repository.
Study context
The Poland data setting is described by Eini, Conradt, and Piniewski (2026), Theoretical and Applied Climatology, doi:10.1007/s00704-026-06322-8. Website results are newly computed with YieldLag 0.2.0 and its documented comparison procedure; they are not a claim to reproduce the paper’s historical metrics.
Data specification
Poland example
| Input | Scope |
|---|---|
| Yield | Provincial crop/aggregate/forage targets, 1999--2019; dt/ha |
| Area | Fixed crop-specific study weights; hectares |
| Weather | Monthly provincial values, 1990--2019 |
| Seasons | Target-specific agricultural-year endpoint assumptions |
Crop yields use dt/ha (100 kg/ha). Area-weight averaging periods and detailed spatial/monthly weather aggregation lineage are unspecified. Weather working conventions are Celsius for MAX/MIN/TAS/DIF, percent for HMD, and monthly mm for PCP; these conventions have not been independently verified against source grids. SLR denotes solar radiation with an unspecified numeric unit/derivation. No automatic unit conversions are applied.
An agricultural year ending in June uses July--December of the previous year and January--June of the harvest year. Seven variables produce 84 monthly terms. The manifest records the term/calendar mapping. Incomplete initial seasonal windows are omitted; requested cutoffs are validated by the workflow.
National references are weighted provincial observations, not independent national measurements. Fixed areas and full harvest-year weather define a retrospective benchmark. Earlier forecasts require inputs available at the intended issue date.
input_sha256.csv records input bytes. Preparation manifests document exclusion
of unused drought indices and derived unweighted national-mean rows; retained
provincial and selected weather values are unchanged.
Data attribution and terms
Climate
Piniewski, M., Szcześniak, M., Kardel, I., and Berezowski, T. (2020), G2DC-PL+: A gridded 2 km daily climate dataset for the union of Polish territory and the Vistula and Odra basins, Version 1, 4TU.ResearchData. https://doi.org/10.4121/uuid:a3bed3b8-e22a-4b68-8d75-7b87109c9feb.
The source catalogue identifies CC0 1.0 Universal: https://creativecommons.org/publicdomain/zero/1.0/. Dataset description: https://doi.org/10.5194/essd-13-1273-2021.
The example contains monthly voivodeship tables derived for the associated study. The source catalogue lists precipitation, minimum/maximum temperature, humidity, and wind. The example also contains temperature difference, mean temperature, and solar radiation. Full aggregation lineage, solar-radiation derivation/unit, and the relationship of these additional columns to the catalogue variables are unspecified. Source CC0 metadata alone do not establish that lineage.
The selected weather values are unchanged; unused drought-index columns were
excluded. weather_preparation.csv records source and distributed SHA-256 hashes.
The tables are study derivatives and carry no provider endorsement.
Agricultural statistics
Source: Statistics Poland (GUS / Central Statistical Office of Poland). The associated study identifies 1999--2019 yield and cultivation-area statistics obtained via https://stat.gov.pl/en/national-census/, last accessed 5 November 2024.
Reuse terms: https://bip.stat.gov.pl/en/contact-with-the-office/reuse-of-public-sector-information/. The provider requires attribution, creation/acquisition-time information, and a processing description, and is not responsible for processed results. Original table identifiers, issue dates, and crop-specific acquisition records are unspecified; the access date above is reported by the associated study.
Processing: provincial values are arranged in crop/year CSV tables with standardized
column labels. Areas are fixed study weights; their averaging period is unspecified.
Derived unweighted national-mean rows are excluded. National reference yields
are computed from provincial observations using the declared area weights.
yield_preparation.csv records filtering and source/distributed hashes.
These derivatives should not be represented as unmodified official GUS products.
Study
Eini, M. R., Conradt, T., and Piniewski, M. (2026), Sequential hybridization enhances the reliability of a statistical crop yield model - exemplified by wheat and sugar beet yields in the provinces of Poland, Theoretical and Applied Climatology, https://doi.org/10.1007/s00704-026-06322-8.
Software license
The MIT license applies to software, not to the provider data. Data users must retain the attribution and processing information above.
Software license
MIT License
Copyright (c) 2026 Mohammad Reza Eini
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.