Concept Schemes & Code Lists

Every classification in a record — the type of an activity, the crop of a cultivation period, the species of an animal — is a concept of a SKOS scheme. Which scheme feeds which attribute is part of the ontology: the schema binds the classification attributes listed below to their scheme, so an application knows which picker to offer and a validator knows what to accept. Some …Uri attributes have no scheme yet — varieties, breeds, cost categories and others; they take any dereferenceable URI, AGROVOC first.

The 17 concept schemes

Each scheme is available at https://w3id.org/agrifooddata/<scheme> (see content negotiation).

Scheme	Holds	Authority	Feeds
`crops`	Crops	BVL code list, with own identifiers; mapped onto AGROVOC in part	`CultivationPeriod.typeUri`, `CroppingPlanEntry.cropUri`, `Stand.cropUri`
`farm-types`	Farm types	AGROVOC	`Farm.farmTypeUri`
`land-use`	Land use	AGROVOC	`Field.landUseUri`
`product-classes`	Product classes	AGROVOC	`Product.typeUri`, `InputOutput.typeUri`
`activity-types`	Types of activity	AGROVOC	`Activity.typeUri`, `Task.typeUri`
`site-types`	Site and storage types	AGROVOC	`Site.siteTypeUri`, `StorageLocation.storageTypeUri`
`machine-categories`	Machine categories	AGROVOC	`Machine.categoryUri`
`device-types`	Device types	AGROVOC	`Device.deviceTypeUri`
`pests`	Pests and disorders	BVL code list; EPPO codes via `CodeMapping`	`Observation.observedPropertyUri`
`observed-properties`	Measured quantities	SOSA/SSN, QUDT, AGROVOC	`Observation.observedPropertyUri`
`animal-species`	Animal species	AGROVOC	`Animal.speciesUri`, `AnimalGroup.speciesUri`
`event-types`	Animal event types	ICAR ADE	`AnimalEvent.eventTypeUri`
`phenology`	BBCH growth stages	BBCH / BVL	`Activity.bbchStage` (by notation)
`regions`	Region types — so far the default region	agrifooddata (own curation)	`Region.typeUri`
`report-types`	Report types	agrifooddata (own curation)	`RegulatoryReport.reportTypeUri`
`soil-glosis`	Soil properties	GloSIS, WRB	`Observation.observedPropertyUri` — scaffold
`environment-envo`	Environmental context	ENVO	— scaffold

Three notes on reading the table:

Observation.observedPropertyUri takes a concept from any of three schemes: observed-properties, pests or soil-glosis. The ontology states this as one restriction over their union.
Alignments to INSPIRE HILUCS (land use) and SAREF4AGRI (device types) are foreseen but not yet substantiated; see Standards the ontology builds on.
Activity.bbchStage is a code, not an identifier: it holds the skos:notation of a concept in phenology ("32"), bound with agfoda:notationFrom instead of a value restriction.
Schemes marked scaffold are structure without substance yet. The ontology says so rather than inventing content.

Identifiers and codes

Everything else in the vocabulary hangs on a distinction between two mechanisms.

	Dereferenceable identifier	Code list
Appears in	`typeUri`, `cropUri`, `speciesUri` …	`externalScheme` + `externalCode` (a `CodeMapping` row)
What sits in the data	an IRI	a code and the register it came from
In RDF	`agfoda:typeUri <IRI>`	`skos:notation` on the concept; a row in the code list
Time	holds indefinitely	`validFrom` / `validTo`; one `isPreferred` per pair
When the authority changes	nothing — the identifier stays	the row gets a `validTo`

The rule in one sentence: stable, globally unique and resolvable → an identifier. Retired, merged or only valid for a period → a code.

AGROVOC is an identifier

A concept with a verified AGROVOC counterpart carries the AGROVOC IRI as its own, in a scheme of ours:

<http://aims.fao.org/aos/agrovoc/c_10795> a skos:Concept ;
    skos:inScheme <https://w3id.org/agrifooddata/activity-types> ;
    skos:notation "fertilization" ;
    skos:prefLabel "Düngung"@de, "Fertilization"@en .

Labels are not redistributed from AGROVOC — only a label of the ontology's own, verified against the AGROVOC service. A client that needs AGROVOC's labels queries AGROVOC.

EPPO is a code

EPPO retires codes and merges taxa, while a plant protection record has to be kept for years. So a crop keeps an identifier of its own, and the EPPO code hangs off it twice — as skos:notation (so it can be searched for) and in the code list (so the mapping can be dated):

# codelists/eppo.csv
conceptUri,externalCode,label,validFrom,validTo,isPreferred
https://w3id.org/agrifooddata/crops#TRZAW,TRZAW,Winterweichweizen,,,true

A code is only recorded where EPPO's code names the organism the BVL names — a code that merely exists is not enough, because some BVL codes are the EPPO codes of another taxon.

Code lists

Five code lists ship with the ontology. Four of them are reached in a record through the data model's CodeMapping entity; the BVL registrations are the exception.

Code list	Role	Notes
EPPO	crop and pest codes	mandatory in German plant protection records; checked against the EPPO database
BBCH	growth stages	the code is also the `skos:notation` of the concept
BVL registrations	authorised plant protection products (Germany)	with validity period; the one list without a concept reference — a registration number denotes a commercial product, and the link is made at the `Product` record (`registrationNumber`)
ICAR ADE	animal event codes	for `event-types`
ISOBUS DDI	machine and process quantities of ISO 11783-11	the DDI rows point at AGROVOC identifiers

Named gaps

A named gap beats an invented row. Where a scheme or code list is foreseen but nothing verifiable exists, the registry says unsubstantiated and gives the reason. Currently so named: KTBL cost categories, the EU variety catalogue (CPVO), FAO DAD-IS breeds, GS1 GTIN, WRB, Crop Ontology, IPCC/GHG categories and ESRS data points. Likewise, the mapping of crops and pests onto AGROVOC is partial — the rest, and the growth stages of phenology, carry no mapping yet. The Recommendation asks for it (clause 7.2); the gap is listed in the data model's divergences.

Standards the ontology builds on

Vocabulary	For
SKOS	the language the concept schemes are written in
SOSA/SSN	observation and sensor in RDF
UCUM	the unit as a string in the data (`"L/har"`)
QUDT	the unit as an IRI in RDF (`unit:L-PER-HA`) — a different layer; never both in one column
GeoSPARQL	geometry in RDF; GeoJSON stays the storage form
PROV-O	provenance, of records and of the vocabulary
OWL-Time	temporal statements beyond ISO 8601
W3C Org	farm, organisation, roles
DCAT-AP	the vocabulary describes itself as a dataset
ISO 19156	the observation model behind SOSA
ISO 4217	currency of every monetary amount
ITU-T Y.4000 / Y.2060	the IoT reference model the classes map onto

Further alignment targets (ITU-T Y.4417, the domain architecture the schema implements; SAREF4AGRI, INSPIRE HILUCS, FOODIE, ADAPT, ISO 19115-1, OGC SensorThings, OGC API – Features, WoT Thing Description) are named with the concrete artefact they would produce; the ontology distinguishes compatible (data can be exchanged or mapped without loss of meaning) from aligned (conceptual correspondence only). Formal conformance is claimed for neither. The full reasoning is in INTEROP.md (as a page).

See it in action

Using the ontology — look a concept up, search, validate
Data model · Entities — the attributes that take these values

The 17 concept schemes​

Identifiers and codes​

AGROVOC is an identifier​

EPPO is a code​

Code lists​

Named gaps​

Standards the ontology builds on​

See it in action​