CAFE Assets

The CAFE framework is more than a set of papers. It is a growing collection of methods, data, software, documentation and case studies, developed by several groups and shared under different terms.

Each entry records the same things: what the asset is, who to contact about it, the terms it is available under, its current status, and where to find it. Assets marked in preparation are not yet public. Assets maintained outside NICCEE are identified as such.

Map of existing CAFE assets, showing datasets and tools arranged across the four nested systems: cropping, animal-crop, food and landscape ecosystem, alongside published and ongoing case studies.

Existing CAFE assets for users in the public and private sectors, in the United States and internationally. The tables below give the detail for each one.

How CAFE developed

CAFE began as a way to identify nitrogen management gaps on and beyond farms, and to give different stakeholders something they could act on. It was built from a review of existing approaches to nutrient budget quantification and management (Zhang et al., 2020). The framework then became the basis of an NSF CAREER project led by Xin Zhang, through which it was developed further with stakeholders and applied across the Chesapeake Bay watershed and in multiple countries (Li et al., 2022; Zou et al., 2024).

Alongside the framework itself, the team has worked with public and private sector partners to co-develop datasets and analytical tools that improve how nutrient flows are quantified across the four systems. For cropping systems, this includes the Nutrient Balance Data Domain, developed with FAOSTAT, the International Fertilizer Association and the research community (Ludemann et al., 2024), and a pipeline for gridded crop nutrient budget maps developed with the FAO Global Soil Partnership and participating countries. For livestock and integrated crop-animal systems, the Global Manure NPK application was developed with support from the International Fertilizer Association to improve how manure nutrient generation and management are represented. Participation in the North American Nutrient Budget Group, and emerging connections with the US National Nutrient Inventory led by the US Environmental Protection Agency, are improving consistency among nutrient accounting efforts.

The same data infrastructure now supports a growing set of analytical and decision-support applications. Tools for agricultural nitrous oxide accounting and target setting are in development with the International Fertilizer Association. CAFE-derived analysis also supports work on the environmental consequences of agricultural trade: the Trade Portfolio tool, published under an MIT licence by its own authors, lets users evaluate the nitrogen pollution and greenhouse gas emissions associated with shifts in trade between animal feed and animal-derived food products. That tool is maintained independently of CAFE, which is the point. A tool does not have to move into the cafeR repository to be part of the ecosystem, as long as its description, provenance and attribution are clear.

Taken together these form a connected set of assets spanning nutrient data, analytical tools and solution resources. Contributed data improve how nutrient flows are quantified. Analytical tools use those data to find management gaps and test scenarios. Solution-oriented resources connect the gaps to interventions and to what has been learned in other regions. This page is where they are listed.

Framework and methods

The peer-reviewed basis of the framework. Anyone applying CAFE should start here.

Publication	What it is	Terms
Zhang et al. (2020)Global Biogeochemical Cycles 34, e2018GB006060	The nutrient budget concept and the definitions of surplus and nutrient use efficiency. doi.org/10.1029/2018GB006060	Publisher terms
Li et al. (2022)Earth’s Future 10, e2022EF002870	The four-boundary CAFE structure and its application at national scale. doi.org/10.1029/2022EF002870	Open access, CC BY-NC-ND 4.0. Non-commercial use, no derivative works.
Zou et al. (2024)Environmental Research Letters 19, 114016	The county-scale Chesapeake Bay application, with the full method in its supporting information. doi.org/10.1088/1748-9326/ad786c	Open access, CC BY 4.0

The three papers do not have the same license. Li et al. (2022) restricts commercial use and adaptation; Zou et al. (2024) does not. Check the terms before reusing figures or tables.

Software and tools

Asset	What it is	Contact	Terms	Status
cafeRR package	An R implementation of the CAFE core calculations and conventions. Computes all four boundaries for any region from a user’s own data, with documentation, visualizations, worked examples and a validation suite tested against published results.	Vanessa Vargas-Nguyen	To be confirmed before release	In preparation
CAFE Chesapeake pipelineMATLAB	The original implementation that produced the published Chesapeake Bay results (Zou et al., 2024).	Tan Zou	To be confirmed	Under discussion with the author
Trade Portfolio toolIndependently maintained	A scenario-analysis tool for the nitrogen pollution and greenhouse gas emissions associated with shifts in animal feed and animal food trade between China and the United States (Wang et al., 2026). github.com/yanyu0729/trade-portfolio-tool	Wang et al., maintained independently of CAFE	MIT License	Available
Global Manure NPK App	A global, interactive tool tracing nutrient use and losses in animal production, from excretion through manure management and recycling to application on cropland. Users can explore current flows and future scenarios, and contribute model data of their own. niccee.org/information-hub/global-manure-npk-model-app	Tan Zou	To be confirmed	Available
Nitrogen Solution Explorer	Connects quantified nutrient-management gaps with the practices, technologies, policies and regional experience that could close them.	Sarah Garvey	To be confirmed	In development
CAFE demonstration app	A browser interface for entering a region’s data and seeing the four-boundary budget, built on cafeR.	Vanessa Vargas-Nguyen	With cafeR	In preparation

Tools do not have to be part of cafeR to be part of the CAFE ecosystem. The Trade Portfolio tool is maintained by its own authors under its own license, and is listed here because it builds on CAFE data and conventions. Independently maintained tools are identified as such.

Data

Asset	What it is	Source	Terms	Status
Cropland nutrient balance dataFAOSTAT Nutrient Balance Data Domain	Nutrient budgets for cropping systems at national scale, for more than 150 countries, 1961 onward (Ludemann et al., 2024). fao.org/faostat/en/#data/ESB	FAO, developed with the International Fertilizer Association and the research community	CC BY 4.0	Published
Gridded nutrient budget maps	Global cropland nutrient budgets at 0.05 degree resolution, showing variation within countries while aligning with the FAOSTAT national dataset. Individual components can be updated as better national or regional data become available (Wang et al., in preparation).	Developed with the FAO Global Soil Partnership and participating countries	To be confirmed	In preparation
Chesapeake Bay CAFE datasetZenodo, 2024	County-level nitrogen and phosphorus budgets at all four boundaries, 197 counties, 1985 to 2019. doi.org/10.5281/zenodo.11399515	Tan Zou	CC BY 4.0	Published
Zou et al. (2024) supporting information	The same budgets as a workbook, with a data dictionary, alongside the method description and parameter tables. doi.org/10.1088/1748-9326/ad786c	Zou et al. (2024), with the publisher	With the CC BY 4.0 article	Published
Chesapeake Bay CAFE DataUS EPA Office of Research and Development	An independent federal catalogue record for the same body of work. doi.org/10.23719/1531967	US EPA	EPA ScienceHub terms	Published
Zhang et al. (2020) figure datasetsDryad	The data behind the 2020 paper’s figures. doi.org/10.5061/dryad.q83bk3jf3	Zhang et al. (2020)	Dryad terms	Published

Regional input datasets used to build a CAFE application are governed by their original providers and are not redistributed here. Anyone reproducing an application should obtain those inputs from the original source.

Case studies

Case study	What it is	Led by	Status
Chesapeake Bay watershed1985 to 2019	197 counties, nitrogen and phosphorus at all four boundaries. The case study that established the county-scale method.	Tan Zou and co-authors	Published
National-scale comparison	The framework applied across countries, showing how the boundaries behave at national resolution.	Li et al.	Published

New case studies are welcome. We are interested in hearing from groups adapting the framework to other watersheds and regions.

Documentation and guidance

Asset	What it is	Contact	Terms	Status
CAFE adaptation guide	How to apply the framework to a new region: what each boundary needs, where the data usually comes from, and what to do when a term is missing.	Vanessa Vargas-Nguyen	Open	In preparation
Method and variable reference	The equations, the fixed conventions, and a dictionary mapping every variable to the names used in the published dataset.	Vanessa Vargas-Nguyen	Open	In preparation
Data policy	What is released openly and what is governed separately, and why.	Vanessa Vargas-Nguyen	Open	In preparation

Adding an asset

If you maintain a method, dataset, tool, model or regional case study that builds on CAFE, we would like to include it. Send the same fields this page uses: what it is, who to contact about it, the terms it is available under, its status, and a link. Assets stay with their authors. Listing here records the relationship to CAFE and makes the collection easier to find.

Citing CAFE

Cite the paper closest to what you used. For the framework, Li et al. (2022). For the budget definitions, Zhang et al. (2020). For the county-scale method and the Chesapeake application, Zou et al. (2024). Software and datasets have their own citations, listed with each entry.