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ERW Meta-Analysis Schema

A LinkML schema for structured extraction of research metadata from 326 Enhanced Rock Weathering (ERW) publications. ERW is a carbon dioxide removal strategy where crushed silicate or carbonate rock is applied to agricultural soils to accelerate mineral weathering, sequester CO₂, and improve soil health.

This schema powers a pipeline that extracts, validates, and verifies structured data from the ERW literature — covering experimental designs, quantification methods, modeling approaches, and socioeconomic analyses.
Articles extracted 325
Experimental setups 209
Interventions (rock amendments) 390
Countries represented 27

Schema Overview

graph TD
    A["Article
study_types · focus_areas · document_type"]

    A --> ES["ExperimentalSetup
experimental_scale · soil · site_location"]
    A --> QA["QuantificationApproach
media · measurements"]
    A --> MD["ModelingDetails
models_used · scale · parameters"]

    ES --> I["Intervention
feedstock · application_rate"]
    ES --> QA

    style A fill:#d1fae5,color:#064e3b,stroke:#059669,stroke-width:2px
    style ES fill:#ede9fe,color:#4c1d95,stroke:#8b5cf6,stroke-width:2px
    style QA fill:#dbeafe,color:#1e3a5f,stroke:#3b82f6,stroke-width:2px
    style MD fill:#fef3c7,color:#78350f,stroke:#f59e0b,stroke-width:2px
    style I fill:#f3e8ff,color:#581c87,stroke:#a855f7,stroke-width:2px

Each Article is the root extraction unit. Depending on its study type, it links to experimental setups (with nested interventions), quantification approaches, and/or modeling details.

When does each class apply?

Not every article has experimental data or modeling. The schema adapts to the type of research:

Study Type Experimental Setup Quantification Approach Modeling Details
Experimental Yes — one per site, with nested Interventions Often — at setup or article level Only if also modeling
Modeling Only if also experimental Sometimes — article-level Yes — model name, scale, parameters
Review No — other studies' data is not extracted Sometimes — article-level No
Perspective No Rarely No

Multiple study types

A paper can have multiple study types. For example, a paper that runs field experiments and fits a reactive transport model would be tagged experimental + modeling and would have both ExperimentalSetup and ModelingDetails.

Quantification at two levels

Quantification approaches can appear at article level (describing the paper's overall measurement approach) or nested within a specific ExperimentalSetup (when tied to a particular site or trial).

Primary Classes

Article

The root entity. Each extraction corresponds to one published paper. Contains study types, focus areas, document type, and links to experimental setups, quantification approaches, and modeling details.

ExperimentalSetup

A distinct experimental context — a site, region, or temporal period. Contains nested Interventions (rock amendments with feedstock characteristics and application rates), soil characteristics, land use, irrigation, site location, and quantification approaches. Multiple treatments within one experiment are separate Interventions, not separate setups.

QuantificationApproach

What was measured and in which medium. Captures the media (soil, water, gas) and specific measurements (cations, pH, DIC, CO₂ flux, etc.) used to quantify weathering or carbon removal.

ModelingDetails

Computational modeling metadata — model names, spatial scale, modeling type, and key parameters. Only populated when study types includes "modeling".

Controlled Vocabularies

The schema uses controlled vocabularies (enumerations) to ensure consistent classification across all 325 articles. See the Enumerations overview for the full list of allowed values with descriptions and ontology mappings.

Key enumerations:

Vocabulary Used for Values
Study Type Research methodology experimental, modeling, review, perspective
Focus Area Research themes quantification, agronomic, soil_health, social_economic, natural_weathering
Experimental Scale Trial scale microcosm, mesocosm, field, catchment
Media Measurement medium soil, water, gas
Measurement What was measured cations, pH, DIC, CO₂ flux, isotopes, ...

All enumerations →

Schema source: github.com/clevinson/erw-meta-analysis · Built with LinkML