🌱 Sampling of soil from natural and cultivated sites according to PN-ISO 10381-4 — standard WITHDRAWN (12-03-2025), source document replaced by the ISO 18400 series

Environment PN-ISO 10381-4

Overview

WHAT LABORATORIES CITE. The accreditation scopes contain PN-ISO 10381-4:2007 — the Polish version, implementing ISO 10381-4:2003 [IDT]. Measurement on the database of scopes (reading of 23.09.2026, across all forms of notation): 49 entries at 47 laboratories; when matching by the BEGINNING of the notation — 44 entries at 42 laboratories, and it is this second number that the "Laboratories" tab shows for this entry.

STATUS (state of the PKN card on 23.09.2026): STANDARD WITHDRAWN. PN-ISO 10381-4:2007, Polish version, publication 23-01-2007, 20 pages, KT 192 General Soil Matters and Soil Physics, ICS 13.080.05, "Implements: ISO 10381-4:2003 [IDT]" — withdrawn 12-03-2025; the card has no "Replaced by" row, so it does not indicate a successor in the PKN catalogue. The status of the document on the INTERNATIONAL side is described in the paragraphs below — read from the text of the successor standard.

THE SOURCE DOCUMENT HAS BEEN REPLACED — AND BY EIGHT DOCUMENTS AT ONCE. The foreword of ISO 18400-104:2018 says literally: this edition, together with ISO 18400-101, -102, -105, -107, -202, -203 and -206, "cancels and replaces the first editions of ISO 10381-1:2002, ISO 10381-4:2003, ISO 10381-5:2005, ISO 10381-6:2009 and ISO 10381-8:2006, which have been structurally and technically revised". That is, five parts of the old series were replaced by eight documents of the new one.

THE SENTENCE THAT DECIDES THE WAY OF TRANSITION. The same foreword states: "The new ISO 18400 series is based on a modular structure and CANNOT BE COMPARED with the ISO 10381 series on a clause-by-clause basis". This means that there is no conversion "clause 8 of the old standard = clause X of the new one" — a laboratory moving to the new series has to write its procedure anew, not swap the number of the reference document. And the same applies to the reader of the scope: the exclusion of a clause in the old standard has no counterpart in the new one.

ONE LABORATORY HAS ALREADY MOVED. In the same database of scopes, one entry cites ISO 18400-205:2018 next to the old standard — so the change has begun, but out of 47 laboratories this is a single case.

WHAT IS EXCLUDED — AND ONLY THIS ONE THING. This standard is cited with clauses excluded by 8 entries at 7 laboratories, and EVERY TIME the same clause 8 is excluded. In the table of contents of ISO 10381-4:2003, clause 8 is entitled "Taking undisturbed soil samples". Clause 7 is the taking of disturbed samples. The difference is substantive: a disturbed sample is taken proportionally to mass, without preserving the arrangement of the soil, and an undisturbed sample — proportionally to volume, by a method that preserves this arrangement (clause 5.7 of the standard). Without an undisturbed sample, the bulk density of the soil and properties dependent on its structure cannot be determined.

THE NOTATION OF THE EXCLUSION IS SOMETIMES SPACED OUT. Among the eight entries are "z wył. p.8", "z wył. p. 8" and "z wył. p k t 8" [all: excluding clause 8] — the last with spaces between the letters of the abbreviation. The numbers above were counted by taking the number only AFTER the word of exclusion and cutting the notation at the next "PN", because one field of reference documents usually contains several standards.

WHAT THE STANDARD COVERS (clause 1). Sampling of soil from natural and near-natural sites; agricultural sites (arable land and pastures); horticultural sites, including domestic and allotment gardens; sites of special cultures, orchards and vineyards; forest and wooded sites. The standard gives strategies for designing sampling programmes, field procedures, and the handling of samples during transport and storage BEFORE sample pretreatment (drying, grinding). It is to be used together with the other parts of the series.

HOW MANY SAMPLES FROM WHAT AREA — THE STANDARD GIVES A TABLE AND A FORMULA. With uniform land use, soil quality and cultivation: up to 2 ha — 1 composite sample; over 2 to 5 ha — 2; over 5 to 10 ha — 3; over 10 to 15 ha — 4; over 15 to 20 ha — 5; over 20 to 30 ha — 6. For larger areas the standard gives the formula n = 1 + √A, where A is the area in hectares.

MINERAL NITROGEN HAS ITS OWN RULES (clause 6.2). Samples are usually taken from three layers: 0–0.3 m, 0.3–0.6 m and 0.6–0.9 m; up to 15 primary samples from a given place and layer form a composite sample. In order not to lose mobile nitrogen, the composite sample is stored at 4 °C, in the dark, in a cooled container, and handed over to the laboratory as quickly as possible. The standard explicitly recommends completing sampling, transport, preparation and determination in the shortest possible time. The number of layers is matched to the maximum rooting depth of the plants.

FOREST SOILS ARE SAMPLED DIFFERENTLY (clause 6.3). Within a forest area unit, at least 10 sample circles are chosen, distributed so that each covers approximately the same number of trees. From the circles, the zones near the trunks (about 1 m from the trunk), the spaces between the trees and the areas under the crowns are sampled separately. From the primary samples taken in this way, composite samples are formed, related to the soil horizon and to the area unit.

HOW MUCH SOIL TO TAKE (clause 5.13). Sandy, loamy and clayey soils — up to 1 kg; peat soils and organic horizons of forest soils — up to 0.5 kg; soils with an increasing proportion of gravel, pebbles and stones — larger masses (reference to ISO 11277). Additional material is needed for duplicate samples.

WHAT THE STANDARD REQUIRES OF CONTAINERS, TRANSPORT AND STORAGE (clauses 5.14–5.16). The container must not introduce the component to be determined, must suit the purpose of sampling, may in some cases require cooling, must prevent losses of volatile substances and water as well as light-induced reactions (stainless steel, fluorinated polymers, aluminium, brown glass), and must have permanent labelling. Transport: as quickly as possible, with cooling if necessary (the standard's example: determination of mobile nitrogen — losses from microbial transformations), avoiding shocks and evaporation of water. Storage: short-term outside the laboratory under suitable conditions, fresh samples in a cold store, and in other cases rapid drying at 40 °C according to ISO 11464.

SUPERVISION AND REPORT (clauses 5.18–5.19). Supervision is to be carried out by personnel with knowledge and experience in soil science and in geological and hydrological matters: selection of equipment excluding cross-contamination and losses, reproducible sampling systems and procedures, estimation of the sampling variability outside the investigated site. The sampling report is to contain information on the site (location and land use, soil conditions, cultivation and climatic conditions) and be supplemented with location sketches, site maps and photographs.

HOW FAR THE AVAILABLE TEXT REACHES. We have a sample extract of ISO 10381-4:2003 (first edition, 2003-05-01): 11 pages of the file, i.e. pages i–5 of the standard — foreword, introduction, the full TABLE OF CONTENTS with clause numbering, clauses 1–5 in full and 6.1, 6.2 and 6.3. We DO NOT HAVE clauses 6.4–6.6 (peat soils, soils of the saturated zone, special types of land use), 7 (disturbed samples), 8 (undisturbed samples), 9 (storage in the laboratory) or Annex A. We therefore know clause 8, i.e. the one excluded by seven laboratories, from its TITLE in the table of contents and from the definition of the sample types in clause 5.7 — not from its content.

WHAT STANDS NEXT TO IT IN THE SCOPES. PN-ISO 10381-5:2009 (investigation of soil contamination on urban and industrial sites) — 29 entries, and PN-R-04031:1997 (the Polish standard on sampling for agricultural analyses) — 16 entries. Matrices: "Gleba" [soil] (31), "Gleby" [soils] (4), "Gleba, grunty" [soil, ground] (3), "Grunty" [ground] (2), "Gleba użytkowana rolniczo" [agriculturally used soil] (2).

NORMATIVE REFERENCES OF THE STANDARD (clause 2): ISO 10381-1 (design of programmes), ISO 10381-2 (sampling techniques), ISO 10381-3 (safety), ISO 10381-5, ISO 10381-6, ISO 11074-1:1996 and ISO 11074-2:1998 (terminology), ISO 11277 (particle size distribution) and ISO 11464 (pretreatment of samples for physico-chemical analysis). The document was prepared by ISO/TC 190 "Soil quality", subcommittee SC 2 "Sampling".

Method principle

A soil sample is taken according to a strategy established before going into the field: the purpose of the test and the land use determine the distribution of sampling points, the type of sample, the depth and the number of primary samples combined into a composite sample. The sampling points are to be representative of the whole area; points that deviate from the average — trampled areas, field margins, waterlogged spots — are deliberately avoided. A disturbed sample is taken proportionally to mass, without preserving the arrangement of the soil; an undisturbed sample — proportionally to volume, in a way that preserves this arrangement. Samples are taken from soil horizons or from layers, with a probe, an auger or from a trial pit.

Applications

• Sampling of soil from arable land, pastures, gardens and sites of special cultures for chemical and physical tests
• Sampling of forest soils and wooded sites
• Sampling for the determination of mineral nitrogen before fertilisation and after the growing season
• Establishing and running soil monitoring plots and sample banks
• Checking whether a laboratory's scope covers undisturbed samples — whether clause 8 is not excluded

Key parameters

Standard

Standard number

PN-ISO 10381-4:2007 (wersja polska; wprowadza ISO 10381-4:2003 [IDT])

Title (PL)

Jakość gleby — Pobieranie próbek — Część 4: Zasady dotyczące postępowania podczas badań terenów naturalnych, zbliżonych do naturalnych oraz uprawnych

Title (EN)

Soil quality — Sampling — Part 4: Guidance on the procedure for investigation of natural, near-natural and cultivated sites

Step-by-step procedure

1. Establishing the purpose of the test (clause 4)

   The sampling strategy follows from the purpose of the test and from the current and previous land use. The standard lists the purposes: gathering information on the general quality of the soil with a view to maintaining and improving its ecological functions; assessing soil quality and the supply of and demand for nutrients; mapping, classification and valuation of soils; establishing and running monitoring plots; duplicate samples for sample banks. Table 1 of the standard assigns to these purposes the importance of horizontal and vertical variability and of changes over time.

2. Setting the sampling points (clauses 5.2–5.6)

   Choose the points so that they are representative of the whole area, taking into account the uniformity of soil quality, the land use and the type of crop. The arrangement of points may be random according to a statistical model or systematic. DELIBERATELY AVOID points that deviate from the average: trampled areas, field margins, waterlogged spots.

3. Choosing the type of sample (clause 5.7)

   Decide whether the test requires a disturbed sample (proportional to mass) or an undisturbed one (proportional to volume, preserving the arrangement of the soil). The latter is the subject of clause 8 — a clause excluded in some accreditation scopes.

4. Deciding: horizons or layers (clause 5.8)

   Sample from soil horizons — appropriate for agricultural, forest and natural land use — or from layers, when the site has been transformed (urban land, mixed soils) or when the purpose of the test requires it.

5. Establishing the number of samples and the depth (clauses 5.11, 6.1)

   For a uniform site, take the number of composite samples from Table 2 of the standard: up to 2 ha — 1, up to 5 ha — 2, up to 10 ha — 3, up to 15 ha — 4, up to 20 ha — 5, up to 30 ha — 6; for larger areas n = 1 + √A. Choose the sampling depth according to the purpose and to representativeness.

6. Sampling — probe, augering or pit (clause 5.9)

   Choose the way of sampling: probing, augering or a trial pit. For the selection of equipment the standard refers to ISO 10381-2. Choose the mass of the sample according to clause 5.13: up to 1 kg for mineral soils, up to 0.5 kg for peat soils and organic horizons, more for stony soils.

7. Mineral nitrogen — special procedure (clause 6.2)

   Sample from three layers (0–0.3; 0.3–0.6; 0.6–0.9 m), combining up to 15 primary samples from a given layer into a composite sample. Store at 4 °C, in the dark, and hand over to the laboratory as quickly as possible — losses of mobile nitrogen are caused by microbial activity. Match the number of layers to the rooting depth of the plants.

8. Forest soils — layout of sample circles (clause 6.3)

   Set at least 10 sample circles in the area unit, covering a similar number of trees. Sample separately from the zones near the trunks (approx. 1 m from the trunk), from the spaces between the trees and from under the crowns; form composite samples from the primary samples, related to the horizon and to the area unit.

9. Transport and storage (clauses 5.15–5.16)

   Transport as quickly as possible, with cooling if necessary, avoiding shocks and evaporation of water. Storage: short-term outside the laboratory under suitable conditions; fresh samples in a cold store; in other cases rapid drying at 40 °C according to ISO 11464.

10. Quality control and report (clauses 5.18–5.19)

    Supervision is carried out by personnel with knowledge of soil science, geology and hydrology: equipment excluding cross-contamination and losses, reproducible procedures, estimation of the sampling variability. The report is to describe the site — location and land use, soil conditions, cultivation and climate — and contain location sketches, maps and photographs.

11. Entering the exclusions in the report

    If the accreditation scope covers the standard with clause 8 excluded, the report is to state this: the laboratory does not take undisturbed samples, so determinations requiring the preservation of the soil arrangement are outside the test carried out.

Required equipment and apparatus

Health and safety (OHS)

• The source document of the standard — ISO 10381-4:2003 — has been replaced by the ISO 18400 series; citing the national standard alone does not tell the reader that on the international side a different set of documents now applies
• The new series cannot be compared with the old one clause by clause — moving to ISO 18400 means writing the procedure anew, not swapping a number in the reference documents
• Excluding clause 8 means that the scope does not cover undisturbed samples — and without them the bulk density of the soil and properties dependent on its structure cannot be determined
• The safety rules for soil sampling are in a separate part of the series (ISO 10381-3), not in this standard — citing part 4 alone does not cover the safety requirements
• A sample for the determination of mineral nitrogen kept without cooling loses the component determined through microbial transformations — the result will be too low, yet it looks the same as a correct one
• Sampling from points that deviate from the average — field margins, waterlogged spots, trampled areas — gives a result that is true for that point and untrue for the area the client asked about

Frequently asked questions