> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agrihub360.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Models Overview

> What each AgriHub360 model predicts, what it reads, and how it is validated.

AgriHub360 runs a set of models on each field. Each has its own page: what it predicts, the published science behind it, how it's applied, which external models it touches, how it's validated, and what it doesn't do.

Most of the models are **mechanistic** or **rule-based**. They apply published relationships, such as thermal time or the FAO-56 evapotranspiration equations, to the weather and readings for a field. None of them measures soil nutrients, and none of them calls a language model.

## Models

### Crop Development

| Model                                      | Type        | Resolution | Predicts                                                                                      |
| ------------------------------------------ | ----------- | ---------- | --------------------------------------------------------------------------------------------- |
| [Growth Stage](/models/growth-stage)       | Mechanistic | Field      | The current Zadoks stage of a planting and the date of the next, from accumulated degree-days |
| [Drilling Window](/models/drilling-window) | Rule        | Field      | Whether soil temperature has held above a crop's threshold for long enough to drill           |

### Field Conditions

| Model                                      | Type | Resolution | Predicts                                                                                                    |
| ------------------------------------------ | ---- | ---------- | ----------------------------------------------------------------------------------------------------------- |
| [Spray Window](/models/spray-frost)        | Rule | Field      | Hours when delta-T, wind and rain allow spraying, and a frost risk                                          |
| [Water Stress](/models/water-status)       | Rule | Field      | Reference evapotranspiration and a banded drought-stress index                                              |
| [Nitrogen Timing](/models/nitrogen-timing) | Rule | Field      | Whether to apply or hold nitrogen, from growth stage, soil temperature, soil moisture and the forecast rain |

### Disease & Pest Risk

| Model                                                     | Type                                                       | Resolution | Predicts                                                                                                                            |
| --------------------------------------------------------- | ---------------------------------------------------------- | ---------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| [BYDV Risk](/models/bydv)                                 | Mechanistic                                                | Field      | When accumulated day-degrees since emergence pass the treatment threshold                                                           |
| [Fusarium Head Blight Risk](/models/fusarium-head-blight) | Published logistic, with a learned model scored against it | Regional   | The probability of an FHB epidemic in the region, from hours of warmth, humidity and rain around flowering                          |
| [Foliar Disease Risk](/models/foliar-disease)             | Mechanistic                                                | Field      | A pressure level per disease for Septoria tritici, yellow rust and brown rust, from hours of leaf wetness at infective temperatures |

## Language & Vision Models

A second group reads what the field models write and turns it into text, or reads a photo. [Scout Photo Diagnosis](/models/scout-diagnosis) names a disease or pest from a leaf photo. The [Field Health Review](/models/field-health-review) synthesises a field's readings, forecast, NDVI and model outputs into a status and actions. [EUDR Document Drafting](/models/document-drafting) writes the due-diligence statement from the farm's records.

| Model                                               | Type           | Reads                                                                                          | Produces                                                                                |
| --------------------------------------------------- | -------------- | ---------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- |
| [Scout Photo Diagnosis](/models/scout-diagnosis)    | Vision model   | A leaf photo, location data stripped and downscaled                                            | A species from a curated list, a confidence and what the model saw                      |
| [Field Health Review](/models/field-health-review)  | Language model | Readings, the weather outlook, the soil sample, the NDVI capture and the field models' outputs | A status, headline, factors and actions, each action with a condition the server checks |
| [EUDR Document Drafting](/models/document-drafting) | Language model | Parcels and dates from the record, your answers and the farm's metadata                        | Sections with headings and body text, rendered to PDF                                   |

## How the Models Run

The field models share one pipeline. Every model reads the same field inputs: the weather, the readings, the soil sample, the planting record and the growth stage. Each input carries the name of its source. A model whose required input is missing skips the field and writes nothing for it, rather than filling the gap with a zero or an estimate. Each model's pure core writes its own row for each run and raises advisories and notifications, so the history of stages, indices and risk values for a field is kept and the field screens read the latest.

## Rules Every Model Follows

* **Skip, don't approximate.** If a required input is missing for a field, the model emits nothing for that field.
* **State the resolution.** A model trained on regional data is labelled regional and is never shown as a per-field result.
* **Report skill against a baseline.** A model that doesn't beat its baseline is shown as its baseline only.
* **Show the uncertainty.** If a number is shown, its interval or confidence is shown with it.
* **Cite the source.** Every threshold traces to AHDB, a peer-reviewed paper or validated field data, named on the model's page.
* **Respect coverage floors.** A model over patchy data under-reads. Below a stated floor, it declines to answer.

## Validation

Models are validated by leaving out a whole season, a whole region, or both, and scoring the held-out predictions against a named baseline. Random cross-validation isn't used: nearby fields in the same season are correlated, so a random split leaks. Each model page states how it's validated and which baseline it's scored against.

## Inputs

Inputs are a gridded weather archive and forecast, an hourly weather series, elevation, your devices and your soil samples. Nutrient values come from soil samples, not from a sensor reading. Each model page lists its inputs, their source, and what the model does when one is missing.