oSIST prEN 17779:2026

oSIST prEN 17779:2026 is the Slovenian draft version of prEN 17779 from the European Committee for Standardization (CEN). It specifies a laboratory extraction method for phosphorus in organic and organo-mineral fertilizers using neutral ammonium citrate, so the phosphorus can be determined afterwards. The document is aimed at fertilizer testing laboratories and at users who need a defined extraction step before phosphorus analysis in these products.

What does oSIST prEN 17779:2026 specify?

oSIST prEN 17779:2026 specifies the procedure for extracting phosphorus from different organic and organo-mineral fertilizers with neutral ammonium citrate. The extraction is the preparation step before the phosphorus determination.

The scope also extends to certain fertilizing product blends. A blend is covered when it contains at least two of the listed component groups and when organic fertilizers or organo-mineral fertilizers are the highest percentage component by mass, by volume, or, for liquids, by dry mass. If another component group is highest, the standard for that highest-percentage group applies. If the components are present in equal quantities, the user chooses which standard to apply.

The document is organized into a foreword, an introduction, clauses 1 to 9, and a bibliography. Clause 2 names the related standards used in the method, Clause 3 points to the vocabulary standards, Clauses 4 to 8 describe the principle, sample preparation, reagents, apparatus and procedure, and Clause 9 sets out the test report items.

What are the key requirements of oSIST prEN 17779:2026?

Check that the sample fits the method

oSIST prEN 17779:2026 is only the extraction step for the product groups in its scope. For fertilizing product blends, the highest-percentage component decides whether this standard applies, unless the quantities are equal, in which case the user chooses the standard. In practice, this means the laboratory has to classify the product before starting the extraction.

Follow the defined principle and linked determination method

Clause 4 states that phosphorus is extracted under specified conditions with a neutral ammonium citrate solution at pH 7. The extract is then analysed according to prEN 17774. In practice, the extraction and the final determination are separate steps, so the extract has to be ready for the same-day analysis required by the method.

Use the prescribed sample preparation route

Clause 5 says sampling is not part of the method, and sample preparation has to follow EN 1482-2. The document points to EN 1482-1 and EN 1482-3 for recommended sampling methods. This matters because the extract result depends on receiving a representative sample that has not been changed during transport or storage.

Prepare and control the reagents carefully

Clause 6 specifies water of low conductivity, ammonium hydroxide solution, crystalline citric acid, and neutral ammonium citrate solution at pH 7. The reagent is prepared and checked so that the pH remains exactly neutral, and a certified commercial solution may also be used. For the analyst, the key point is that the reagent condition is part of the method performance.

Use the required apparatus and extraction conditions

Clause 7 calls for common laboratory glassware, a pH-meter, a water bath set at 65 ± 2 °C, and phosphate-free filter paper. Clause 8 requires a defined test portion, then extraction with 100 ml of reagent, stirring for 60 ± 1 min at temperature, cooling, quantitative transfer, dilution to volume, and filtration. These fixed conditions matter because time, temperature and suspension control affect how much phosphorus enters the extract.

Document the result traceably

Clause 9 requires the test report to identify the sample, cite the method, record sampling details if known, state when extraction finished, and note any optional operations or incidents that could have influenced the result. In practice, this supports comparison between laboratories and later review of the test outcome.

What terms does oSIST prEN 17779:2026 define?

The document uses the vocabulary in EN 12944-1 and EN 12944-2. The following terms are the ones a reader needs most.

• Fertilizing product blend - a mix of at least two listed component groups, such as fertilizers, liming materials, soil improvers, growing media, inhibitors, and plant biostimulants.
• Organic fertilizers - one of the product categories used to decide whether this method applies to a blend.
• Organo-mineral fertilizers - the other main product category covered by the extraction method.
• Test portion - the measured portion of the laboratory sample taken into the Erlenmeyer flask for extraction.
• Extract - the liquid obtained after the ammonium citrate extraction and filtration, used for phosphorus determination.
• pH-meter - the instrument used to set and check the neutral ammonium citrate solution at pH 7.

Who uses oSIST prEN 17779:2026?

oSIST prEN 17779:2026 is used by laboratories that analyse fertilizers and fertilizing product blends. It is relevant for producers and quality control teams working with organic fertilizers, organo-mineral fertilizers, and blends that contain these materials.

It also supports technical staff who prepare samples, run wet-chemical extractions, and send extracts for phosphorus determination by prEN 17774. Buyers, inspectors, and specification writers may use it to agree on a common extraction method before phosphorus is reported.

What changed in oSIST prEN 17779:2026 from the previous edition?

oSIST prEN 17779:2026 will supersede CEN/TS 17779:2022. The foreword lists these significant changes:

• the CEN Technical Specification has been adopted as a European Standard
• the title has been adapted
• an Introduction has been added
• Clause 1 Scope has been updated, including clarification on fertilizing product blends and the analytical method to use
• Clause 6 Reagents has been added
• Clause 9 Test report has been added
• the Bibliography has been updated

Which standards are used with oSIST prEN 17779:2026?

• prEN 17774 - gives the phosphorus determination step after extraction, by ICP-AES after extraction by water and weak solvents.
• EN 12944-1 - provides general terms for fertilizers and liming materials.
• EN 12944-2 - provides fertilizer-related terms used with this method.
• EN 1482-2 - gives the sample preparation rules used before extraction.
• EN 1482-1 - is cited for recommended general sampling provisions.
• EN 1482-3 - is cited for sampling of static heaps.

What does the oSIST prEN 17779:2026 document contain?

The document contains the principle of extracting phosphorus with neutral ammonium citrate, the sample preparation route, reagent preparation, apparatus requirements, and the step-by-step extraction procedure. It also gives the conditions for the test portion, heating, stirring, cooling, transfer, dilution, and filtration.

It includes a reporting clause so laboratories record the sample identification, the method used, and any events that could affect the result. The bibliography points readers to the EU fertilising-products regulation and the related sampling standards.