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March 2026 Release

· 7 min read
Sven Verweij
Sven Verweij
Project Manager @ NMI

The March 2026 release introduces two new packages — fdm-rvo for connecting to the Dutch RVO agricultural registry and fdm-agents with an AI-assisted fertilizer planning tool in Labs — alongside a substantial rework of the fertilizer management interface, organization-level balance visualizations, and several data quality corrections in the fertilizer catalogue.

RVO Field Import​

A new package, @nmi-agro/fdm-rvo, has been added to the monorepo. It provides the synchronization logic for connecting FDM to the Dutch agricultural authority (RVO) and importing field registrations.

FDM Application (@nmi-agro/fdm-app)

  • Farm create wizard: A step has been added to the farm creation wizard to import fields directly from RVO during onboarding.

  • Fields page: Existing farms can also import or update fields from RVO via the fields page. The feature is available behind a feature flag for deployments that have RVO connectivity configured.

  • Shapefile handling: When importing a shapefile, parcels without a recorded name are assigned a fallback label, preventing failed imports for unlabelled fields.

Fertilizer Management​

The fertilizer catalogue view and the add-fertilizer workflow have been substantially redesigned.

FDM Application (@nmi-agro/fdm-app)

  • Nutrient columns: The fertilizer table now includes columns for DS, OS, MgO, CaO, Na₂O, SO₃, and trace elements. Columns can be toggled on and off via a "Kolommen" dropdown, keeping the default view uncluttered.
  • Searchable catalogue: The catalogue picker replaces the previous card grid with a searchable list. Standard and custom fertilizers are visually distinguished, and RVO category badges indicate classification.
  • Updated form: Numeric input fields are now arranged in a three-column grid for easier data entry. The application method section has been reorganised.
  • Summary sidebar: The "Samenvatting" sidebar now calculates the effective nitrogen content ("Werkzame N") live as inputs change.
  • Navigation: Rows in the fertilizer table are now clickable. A "Gebruik als sjabloon" option allows creating a new fertilizer based on an existing one.

FDM Data (@nmi-agro/fdm-data)

  • Broadcasting: The broadcasting application method has been added to the available options for solid manure (vaste mesten) and compost, reflecting that these products can be applied by broadcasting in practice.
  • Fertilizer data corrections: Dry matter content and density values for several liquid mineral fertilizers have been corrected:
    • BAAT003 (Ammoniumnitraatureanoplossing UAN): p_dm corrected to 750 g/kg, p_density to 1.3 kg/L
    • BAAT004 (APP 10-34-0): p_dm corrected to 560 g/kg, p_density to 1.39 kg/L
    • BAAT044 (NTS 27): p_dm corrected to 345 g/kg, p_density to 1.32 kg/L
    • BAAT057 (UAN): p_dm corrected to 750 g/kg, p_density to 1.3 kg/L
    • BAAT059 (Ureum 20% liquid): Name corrected; p_dm corrected to 429 g/kg, p_density to 1.09 kg/L, nitrogen composition corrected
    • BAAT027 (Kalksalpeter): p_ca_rt value corrected

Farm and Organization Balances​

FDM Application (@nmi-agro/fdm-app)

  • Organization-level balance plots: Nitrogen and organic matter balance results are now available at the organization level, showing farm-by-farm results in a single overview. Individual farms can be excluded from the view.

FDM Calculator (@nmi-agro/fdm-calculator)

  • Farm-level aggregation: Two new functions support collecting input data and aggregating results across all farms in an organization:
    • collectInputForNitrogenBalanceForFarms
    • collectInputForOrganicMatterBalanceForFarms
  • Uncached calculation APIs: New public functions allow running calculations without the cache layer, useful for integration scenarios and testing.
  • Nitrogen balance correction: The farm-level nitrogen balance no longer includes nitrate leaching, correcting an error in the previous aggregation logic.

FDM Core (@nmi-agro/fdm-core)

  • Catalogue access functions: New composable functions replace the previous monolithic catalogue queries:

    • getEnabledCultivationCataloguesForFarms and getEnabledFertilizerCataloguesForFarms return the catalogues enabled per farm.
    • getCultivationsFromCatalogues and getFertilizersFromCatalogues retrieve entries from a given set of catalogues.

    These are composable: callers can first fetch catalogues, then pass them into the item-retrieval functions, enabling deduplication across multiple farms.

  • Farm-level batch query functions: New functions retrieve all data for a farm in a single query, eliminating N+1 round-trips when processing all fields of a farm at once.

AI Fertilizer Planning Assistant (Labs)​

A new package, @nmi-agro/fdm-agents, introduces an AI-based tool for supporting fertilizer planning decisions. The initial release includes Gerrit, an assistant designed to propose fertilizer application plans at the field and farm level.

Gerrit operates with a reasoner–verifier architecture: the language model handles planning reasoning, while all norm calculations and balance checks are performed by the deterministic fdm-calculator. The following planning strategies are supported: organic farming, derogation (no mineral phosphate), fill-manure-space, NH₃ emission reduction, nitrogen balance target, and rotation-level (bouwplan) consistency.

In the FDM application, Gerrit is accessible via the farm sidebar. A strategy configuration form allows users to specify their planning context; the resulting fertilizer plan is displayed in a table alongside norm progress indicators. A feedback button is provided for rating and commenting on outputs.

The feature is available as a Labs feature and can be enabled through a dedicated feature flag.

  • Soil analysis: The soil analysis pages now include header breadcrumbs and a back button, making navigation between analyses, uploads, and field details more consistent.
  • Crop residue: The crop residue option in the rotation table is now disabled when the selected crop has no effective organic matter residue, preventing entries that would have no effect on the organic matter balance.
  • Fields table: A buffer strip checkbox column has been added to the fields table, making it straightforward to check or update the buffer strip designation for each individual field.
  • Atlas: A button has been added to focus the Atlas map on the farm's own fields. When in the process of adding new fields, the focus area also updates to include newly selected parcels.

Technical Improvements​

  • Minimum Node.js version: All packages in the monorepo now require Node.js 24 or higher.
  • Authentication: better-auth has been updated to version 1.5.
  • Soil analysis storage: The a_nmin_cc parameter is now stored correctly when submitting a soil analysis.
  • Calculator bug fix: A falsy-value check in the calculator has been corrected to preserve 0 and false as valid inputs. Previously, a field with a legitimate value of zero — such as zero organic matter content or zero nitrogen supply — could be treated as missing, leading to incorrect results in downstream calculations.
  • GeoTIFF reliability: Processing of GeoTIFF files now uses hybrid buffer loading (files ≤2 MB are buffered in memory), concurrency throttling via a semaphore, and exponential backoff with a 10-second timeout, reducing the frequency of intermittent fetch errors.
  • Fertilizer type: Missing parameters have been added to the Fertilizer type in fdm-core, improving type completeness.
  • Calculator batch queries: All input collectors for balances and norms now use farm-level batch queries instead of per-field loops, eliminating N+1 database round-trips for large farms.
  • Crop residue nitrogen removal: A bug in the nitrogen balance has been fixed: residues left on the field are no longer counted as removed nitrogen, while residues that are removed from the field are now counted correctly.

For a detailed list of changes, please refer to the package-specific changelogs for fdm-app, fdm-calculator, fdm-core, fdm-data, fdm-rvo, and fdm-agents. Feedback and contributions are welcome on our GitHub repository.