🌿 Available zinc in mineral soil — flame atomic absorption spectrometry (FAAS), PN-R-04016

Environment PN-R-04016

Overview

WHAT THE STANDARD COVERS. The scope from the PKN catalogue card, quoted in full: "The principle of the method consists in selective absorption of radiation of wavelength 213.8 nm, emitted by a zinc cathode lamp, by zinc atoms formed when the test solution is nebulised in an acetylene-air flame. An assessment of the zinc content is given (in a table)." The card does not say what the soil extract is prepared with — that is stated in the second source (below).

STATUS (state of the card on 28 September 2026). The card carries the heading "Withdrawn" and the row "Date of withdrawal: 15-11-2012". There are no "Superseded by" and "Supersedes" fields. Edition: published 30-06-1992, 2 pages, PKN technical committee KT 90 (Soil Cultivation and Horticulture), ICS 13.080.10. The PKN search for "przyswajalnego" (available) (29 September 2026) shows only standards of the same series — PN-R-04016 … PN-R-04025 of 1992–1997 and two amendments to them (Az1:2002, Az1:2004) — a successor WE HAVE NOT ESTABLISHED. A regulation citing this standard as a test method WE HAVE NOT ESTABLISHED.

EXTRACT AND TECHNIQUE — ACCORDING TO A PUBLICATION OF THE NATIONAL AGRICULTURAL CHEMISTRY STATION. W. Lipiński (National Agricultural Chemistry Station), "Zasobność gleb Polski w mikroelementy" (Micronutrient status of Polish soils), Studia i Raporty IUNG-PIB 34(8), 2013, pp. 121–131: in the agricultural chemistry stations copper, zinc, manganese and iron in mineral soils are determined after extraction with hydrochloric acid solution of concentration 1 mol/dm³, by AAS; the common 1 mol/dm³ HCl solution was introduced in 1986 on the initiative of IUNG and — as the author writes — "despite broad criticism, the method was standardised and is still used today" (our translation). Earlier (1965–1983) zinc was extracted according to Sommer and Wear with 0.1 N hydrochloric acid and determined colorimetrically. The result is therefore "available" zinc in a conventional sense: what passes into this extract, not the total zinc content of the soil.

CONTENT ASSESSMENT — THE TABLE FROM THE STANDARD. We cite the same publication for the limit values (Table 5, "Source: PKN, 1992"), mg of zinc per kg of soil: very light soil — low below 0.7, medium 0.7–3.3, high above 3.3; light — below 1.4, 1.4–6.3, above 6.3; medium — below 4.6, 4.6–20.5, above 20.5; heavy — below 11.5, 11.5–51.1, above 51.1. In 2009–2012, according to this assessment, 17 % of the soils tested by the stations had a low content, 59 % a medium and 24 % a high content (Table 9 of the publication). In 2013 the author writes (p. 122): "The currently applicable limit values used to evaluate soils for their micronutrient content are presented in Tables 1–7 (…)" (our translation); whether the stations apply them in this form today — WE HAVE NOT ESTABLISHED. For organic soils the publication gives a separate table with a different extract (0.5 mol/dm³ HCl): zinc low below 20, medium 20–40, high above 40 mg/kg.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17 September 2026, read on 28 September 2026). All records of number R-04016: 16 entries at 16 laboratories — each has one entry, and the same 16 laboratories cite the standards on available copper, manganese and iron of this series. Two forms: "PN-R-04016:1992" — 10 laboratories; "PN-92/R-04016" — 6 (AB 317, AB 333, AB 759, AB 789, AB 798, AB 921). The "Laboratories" tab searches for records BEGINNING with "PN-R-04016" and will show 10 laboratories; it will not show the six with the form "PN-92/R-04016". The test object is mineral soil; AB 277 has in this entry a separate range for organic soils (10.0–80.0 mg/kg), and AB 317 writes "mineral and organic soils" with a single range. All 16 record the FAAS technique (AB 1186 in the test-description field). Current scopes on the PCA website (read on 29 September 2026): all 16 entries stand in the valid issues with the same range as in the copy, and none is suspended.

CLAUSES OF THE STANDARD IN THE SCOPES. AB 333 cites the standard "excluding clause 3.5", and AB 787 "excluding clause 3.5b"; AB 333 also excludes clause 3.5 in the standards on copper, manganese and iron of this series. What clause 3.5 contains — WE HAVE NOT ESTABLISHED.

RANGES AND CLASS LIMITS — A PLACE FOR A RESULT THAT CANNOT BE CLASSIFIED. The accreditation range of 13 of the 16 laboratories starts above 0.7 mg/kg — the limit between low and medium content in very light soil; the exceptions are AB 333 (from 0.27), AB 277 (from 0.5) and AB 787 (from 0.7). Seven also start above 1.4 mg/kg, the limit for light soil: AB 284, AB 312, AB 317, AB 823, AB 930 (from 1.8–2.0), AB 798 and AB 1172 (from 5.0) — the last two also above 4.6 mg/kg, the limit for medium soil. At the top, four ranges end below 51.1 mg/kg, the high-content limit in heavy soil: AB 277 (up to 32.0), AB 779 (up to 35.0), AB 787 and AB 1172 (up to 50). A result "below the range" or "above the range" for such a soil does not decide the class — this has to be checked in the report before the nutrient status is assessed.

WHAT WE DO NOT GIVE. We did not have the text of the standard — PKN sells it (2 pages). We do not give the sample mass, the extraction volume and time, the soil preparation, the spectrometer operating conditions beyond the wavelength and flame from the card, the calibration curve, the formula or the precision.

Method principle

According to the card of the standard: zinc in the solution from the soil sample is determined by flame atomic absorption spectrometry — zinc atoms formed in an acetylene-air flame absorb radiation of wavelength 213.8 nm from a zinc cathode lamp. According to the publication of the National Agricultural Chemistry Station (2013), the solution is an extract of mineral soil with hydrochloric acid of concentration 1 mol/dm³, common for zinc, copper, manganese and iron. The result in mg/kg is assessed according to the table from the standard, separate for four soil texture categories. We DO NOT GIVE the sample mass and extraction conditions — we did not have the text of the standard.

Applications

• Assessment of the available-zinc status of mineral soils for fertiliser advice — in accreditation scopes exclusively agricultural soil-testing stations (16 laboratories)
• Assessment according to the table from the standard: the class depends on the result AND on the soil texture category, so the result is reported together with the category
• Not for organic soils: the KSChR publication gives a different extract for them (0.5 mol/dm³ HCl) and different limit values; AB 277 and AB 317 also cover organic soils with this standard

Key parameters

Standard

Standard number

PN-R-04016:1992 (wersja polska)

Title (PL)

Analiza chemiczno-rolnicza gleby — Oznaczanie zawartości przyswajalnego cynku

Title (EN)

Agricultural chemical analysis of soil — Determination of available zinc content

Step-by-step procedure

1. Status of the document

   PKN card: standard withdrawn on 15-11-2012, no successor indicated (state of the card on 28 September 2026). In the report the full designation with the year is given: PN-R-04016:1992.

2. Sample preparation and extract

   Mineral soil is extracted with 1 mol/dm³ hydrochloric acid (according to the KSChR publication). Sample mass, time and shaking method NOT GIVEN.

3. Measurement

   Zinc is determined in the extract by flame atomic absorption spectrometry at 213.8 nm, in an acetylene–air flame.

4. Result

   The available-zinc content is reported in mg/kg of soil. Check whether the result lies within the laboratory’s accreditation range.

5. Content assessment

   The class (low, medium, high) is read from the table for the soil texture category. A result "below the range" in very light or light soil does not decide the class if the range starts above 0.7 or 1.4 mg/kg.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Hydrochloric acid is corrosive — work with gloves and goggles, in a fume cupboard; its safety data sheet applies
• Acetylene is extremely flammable — the spectrometer’s gas installation must be leak-tight and have the manufacturer’s safeguards
• TECHNICAL NOTE: the content class depends on the soil texture category — the same result may be a high content in very light soil and a low one in heavy soil

Frequently asked questions