Spain's digital farm notebook and SIEX: what is mandatory, from when, and your options

If you work with farms in Spain, you have heard over the last two years that the digital farm notebook was mandatory, then that it was not, and now that plant protection records are. All three were true at different moments. This guide sorts out what SIEX is, what the digital farm notebook (Cuaderno digital de explotación agrícola, or CUE) is, which dates are in the Official State Gazette and which are only expectations, and what options you have to comply: the public app, commercial software, or a custom build that connects the systems you already run. It is written for agribusinesses, cooperatives, agronomy consultancies and agtech startups that handle data for many farms, not just one.

What is SIEX and how does it relate to the digital notebook?

SIEX is Spain's information system for agricultural and livestock holdings and farm production. It is governed by Royal Decree 1054/2022, which sets up three pieces at once: SIEX itself, which runs at national level; the regional register of agricultural holdings (REA), managed by each autonomous community; and the digital farm notebook, known as CUE.

The underlying idea is easy to explain and hard to deliver: a farmer enters a piece of data once and it travels to every administration that needs it, instead of being retyped for the CAP application, the plant protection register and each inspection. The CUE is where day-to-day activity goes: treatments, fertilisation, field work, harvests. The REA holds the structural data of the holding. SIEX is the layer that connects them.

For anyone who has kept a paper field notebook for years, the change is less about what gets recorded and more about how. A digital notebook can validate data as it is entered (a dose out of range, a product not authorised for that crop) and send it on without retyping. That is where the real value is, and also where the technical complexity sits once many holdings are involved.

Is the digital farm notebook mandatory? The dates that are actually law

This is where most of the confusion lives, so let's take it step by step. The original SIEX timetable phased in the digital notebook from 2023. In January 2025 the government changed course: Royal Decree 34/2025, published on 22 January 2025, made the digital format optional. The Ministry of Agriculture presented this as temporary, until the next programming period of the CAP Strategic Plan, which the Ministry places from 2027 onwards. When digital becomes compulsory again across the board will depend on how the next CAP is settled, so do not treat any date as fixed.

What became optional is the format, not the duty to keep records. Plant protection treatments, fertilisation and CAP-related data still have to be recorded. You can do it on paper or electronically, but you have to do it.

Plant protection products are the important exception. EU Implementing Regulation 2023/564 requires records of plant protection product use to be kept electronically. On 18 November 2025 Spain approved Royal Decree 1039/2025, which allows those records to stay on paper until 31 December 2026. In practice: from 1 January 2027, phytosanitary treatment records must be digital.

A second date affects the same notebook. After the amendment to Royal Decree 1051/2022 on sustainable soil nutrition, approved on 21 October 2025, recording all fertilisation work in the farm notebook has been required since 1 January 2026, on paper or digitally and with the exceptions set out in the rule. So today the notebook must already cover fertilisation, and in three months its plant protection records must be electronic.

Who is affected and what has to be recorded?

It applies to holders of agricultural holdings and to professional users who apply plant protection products. In practice, though, the workload often does not fall on the farmer. It falls on the cooperative that runs the spraying service, the company managing land for third parties, or the technical adviser who keeps the notebooks of dozens of members or clients.

For plant protection products, the record covers at least the product applied, the pest or reason for the treatment, date and dose, the plot and crop treated, who applied it and with what equipment. For fertilisation, whatever the sustainable nutrition rules and the fertilisation plan require. Each autonomous community sets the details and the tools, so your regional agriculture department is always the final reference.

If you are a company or cooperative already handling many holdings, the useful question is not whether this affects you, but how many times you will type the same data. If your advisers already log treatments in a spreadsheet, in the cooperative's ERP or in a field app, copying them by hand into each holding's digital notebook doubles the work and multiplies the errors.

What options are there for keeping the digital notebook?

The first is the public app. The Ministry offers a free CUE app and several regions run their own, such as CUECYL in Castilla y León or Aragón's platform. For a small holding that keeps its own records, this is usually enough: it costs nothing, it matches what the administration asks for and it is updated when the rules change.

The second is commercial farm notebook software. The rules allow any system that meets the technical requirements, and some regions keep a register of commercial CUE software developers. In Extremadura, for example, registration requires compliance with the SIEX technical coordination document. It is a good fit when you need more than the public app (several users, reports, product stock) and the way you work matches the product.

The third is custom software that does not replace the notebook but feeds it from the systems you already have: the cooperative's ERP, your advisers' app, irrigation sensors, satellite vegetation indices or the plant protection product store. It is not for everyone, and below we explain when it makes sense.

A word of caution on SIEX integration. Technical specifications and exchange channels are set by the Ministry, FEGA (the Spanish agricultural guarantee fund) and each region, and they have changed over time. Before committing to a build, check with your autonomous community or the Ministry which exchange format is current and what a third-party system must comply with. Any vendor promising a direct connection without reviewing that with you first is overselling.

When does custom software make sense?

Almost never for a single farm. If you have one holding and one adviser, the public app or a good commercial product solves the problem for far less than any custom build.

It starts to pay off when several of these apply. You handle data for many holdings at once, as a cooperative, agronomy consultancy or services company. The treatment data already exists in another system (the ERP where the product is invoiced, the app where the adviser signs the prescription) and copying it by hand is your bottleneck. You have automatic sources such as sensors or satellite data that you want to combine with the notebook. Or you are an agtech startup whose product needs to read and write notebook data as part of the service.

In those cases the typical work is an integration layer: a service that collects data from your systems, validates it against the rules, converts it to the format your region or your CUE software accepts, and keeps a trail of what was sent and when. It is the same kind of project we describe in custom ERP and CRM integration via API, applied to the field. If you also want to follow each batch from plot to customer, it ties in with what we cover on food traceability software.

If everything currently lives in spreadsheets shared between advisers, the first step is not connecting to anyone but getting the data into a proper system of your own. We walk through that path in from Excel to custom software.

What would an illustrative cooperative case look like?

This is an illustrative example, not a real client. Picture a cooperative with an advisory service covering several hundred members. Advisers visit plots and recommend treatments, and the member buys the product at the cooperative shop, which invoices it from its ERP. Today each treatment is written down three times: on the adviser's prescription, in the ERP sale, and in the member's farm notebook, which the cooperative itself often fills in at the end of the season.

A sensible build replaces nothing that works. It adds a simple mobile app so the adviser logs the recommendation on the plot, even without coverage, and syncs it later. It matches that recommendation against the ERP sale to know which product and batch the member took. And it prepares each holding's records in the format accepted by the digital notebook each member uses, with a review screen before anything is sent.

The value is not compliance, which the free app already provides. The value is no longer typing the same thing three times, having clean data for audits and certifications, and offering the notebook as one more service to members. If the cooperative's ERP already has an API, the scope shrinks a lot. If not, part of the project is building that connection, as we explain in our API guide for businesses.

Where should you start before 1 January 2027?

First, map where each piece of data is born today: who decides the treatment, where it is written down, where the product is invoiced and who fills in the notebook. There is almost always a manual step nobody had counted as work.

Second, ask your autonomous community which public CUE it offers, whether it keeps a register of commercial software and which technical specifications currently apply for a third party to submit data. That tells you whether your problem is solved by choosing a tool or whether you need to integrate.

Third, if you do need to integrate, start with the piece that saves the most hours rather than everything at once. A first module, such as the field app connected to the ERP, can be scoped as an MVP from €1,500 in 2-4 weeks, with fortnightly sprints where you see real progress. Integrations spanning several systems and regulatory validation take longer and cost more, and it is better to have that in writing before you start.

Three months is little time for a large project, but enough to decide well and have the plant protection piece ready. What you want to avoid is reaching December without knowing who will enter each holding's data, and with which tool.