A Munsell soil color chart is a standardized reference book of mounted color chips that lets field staff describe soil color the same way, every time, regardless of who's holding the trowel. This guide covers how to read the hue-value-chroma notation, what soil color actually tells you on a site assessment, and which ERE-stocked chart to specify for Canadian fieldwork.
What Is a Munsell Soil Color Chart?
A Munsell soil color chart is a bound reference of color chips — organized by hue page, with value and chroma varying across each page — that a field technician holds directly against a soil sample to find the closest visual match. It's the field version of the same Munsell color system used in paint, printing, and geology, adapted specifically for the range of colors soils actually occur in (reds, browns, yellows, and the grays/greens of waterlogged soil), developed originally with the U.S. Soil Conservation Service and now the standard reference cited across Canadian and U.S. soil description protocols.
The point of the chart isn't aesthetic — it replaces subjective color language ("brownish-gray," "rusty") with a repeatable code that means the same thing whether it was logged by a junior field tech in Sudbury or a senior geoscientist in Fort McMurray.
How Do You Read Hue, Value, and Chroma?
Every Munsell soil color notation has three parts, always recorded in the same order: hue, value, chroma. Once you can read the three axes, matching a chip is mechanical.
| Dimension | What it measures | Typical soil range |
|---|---|---|
| Hue | The color family itself (red, yellow, green, etc.) | Soil charts cover 10R through 5Y, plus the gley (N, GY, G, BG) pages for saturated/reduced soils |
| Value | Lightness to darkness, top to bottom on the page | 0 (black) to 10 (white); most mineral soils fall 2–8 |
| Chroma | Color intensity or saturation, left to right on the page | 0 (neutral gray) to 8; higher chroma = more saturated, "purer" color |
Notation is written hue, then value over chroma — 10YR 3/2 reads as "hue 10YR, value 3, chroma 2," a dark grayish-brown. That string, not a color name, is what belongs in a boring log, a Phase II ESA field form, or a wetland delineation datasheet.
What Does Soil Color Tell You on a Site Assessment?
Soil color is a direct visual record of the soil's redox history and mineral content, which is why it's a required field observation on Canadian Phase II Environmental Site Assessments, not just a geotechnical formality.
- Red, orange, and strong-brown hues (high chroma) indicate oxidized iron — well-drained, aerated conditions.
- Gray, blue, and green "gleyed" hues (low chroma, N/GY/G/BG pages) indicate reduced iron from prolonged water saturation — the standard visual trigger for hydric soil and wetland delineation calls.
- Mottling — patches of contrasting color within one horizon — signals a fluctuating water table, a common cue in septic-system siting and groundwater-depth estimation.
- Unusual staining (black, orange-red sheen, or colors that don't fit the natural soil profile) is a standard field trigger for suspected petroleum or metals impact, prompting field screening or lab confirmation.
ASTM D2488, Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) — the reference most Canadian geotechnical and Phase II field logs are built around — specifies Munsell notation as the method for recording soil color, moist unless otherwise noted. On the regulatory side, the CCME Phase II Environmental Site Assessment Technical Guidance lists soil color and staining as core field observations consultants are expected to log at every borehole and test pit.
Which Munsell Chart Should You Use for Fieldwork?
ERE stocks the Munsell Soil Color Chart Binder — the standard field-durable edition environmental and geotechnical consultants specify for boring logs and Phase II work.
| Spec | Detail |
|---|---|
| Format | Bound binder, 6" × 7.75" × 1" |
| Weight | 3 lbs (1.3 kg) |
| Coverage | 440+ color chips across 12 hue chart pages |
| Chip mounting | Water-resistant, recessed — holds up to repeated field contact with wet soil |
| Edition | 2009 Revised Edition |
The 12-page hue spread covers the full range field crews actually encounter — including the gley pages needed for wetland and hydric-soil calls — in a single binder sized to fit a field pack rather than a lab shelf. For the rest of the soil-description toolkit — augers, core samplers, and split-spoon samplers — see ERE's soil sampling equipment guide and the full soil sampling equipment collection.
How Do You Match a Soil Sample to the Chart in the Field?
- Break the sample fresh. Split or break the soil to expose an unweathered, unsmeared face — a trowel-smeared surface reads differently than a natural break.
- Moisten if the sample is dry. Munsell notation is conventionally recorded moist; note "dry" on the log if you can't moisten the sample in the field.
- Read it in daylight or a daylight-equivalent lamp. Fluorescent and incandescent light shift the apparent hue — never match indoors under standard shop lighting.
- Hold the soil directly against the chip openings so the sample and chip are touching, not compared side by side at a distance.
- Find the closest chip — if the sample falls between two chips, record the closer one and note the split (e.g., "10YR 4/3 to 4/4").
- Record hue, value, chroma in that order on the boring log or field form, plus a plain-language descriptor (e.g., "10YR 4/3, dark brown") for readers who aren't trained on Munsell notation.
For the broader Phase II field kit this fits into, see ERE's Phase II ESA equipment checklist.
Need a Munsell chart or the rest of your soil sampling kit?
ERE Inc. has supplied environmental and geotechnical field equipment to Canadian consultants for 30+ years — tell us what your program needs and we'll quote it.
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Frequently Asked Questions
Is the Munsell system still used for soil description today?
Yes. Munsell notation remains the standard method for recording soil color in ASTM D2488 (the visual-manual soil description standard) and in Canadian Phase II Environmental Site Assessment field protocols — it hasn't been superseded by a newer system.
Should the soil sample be wet or dry when matching it to the chart?
Moist, by convention. Soil color reads darker and more saturated wet than dry, so most protocols record the moist color and note "dry" explicitly if the sample can't be moistened in the field.
What does a gray or green soil color mean on a site assessment?
Gray, blue, or green (gleyed) coloring indicates reduced iron from prolonged water saturation — it's the standard visual trigger for hydric soil and wetland delineation calls, and it's also relevant to interpreting groundwater conditions at depth.
Can I use a phone app instead of a physical Munsell chart?
Camera-based color-matching apps exist, but screen and camera color rendering vary by device and lighting, and most regulatory field protocols (including ASTM D2488) reference the physical chip chart as the description method — a physical chart is still what Canadian consultants specify for defensible field logs.
Related articles
- Soil Sampling Equipment in Canada: Augers, Core Samplers, and Split Spoons
- Phase II Environmental Site Assessment: Equipment Checklist for Canadian Consultants
- Environmental Sampling Equipment Guide for Canada
Lire en français : Charte de couleur des sols Munsell : guide de terrain pour les évaluations au Canada