Lab 09: BC Soils and Relationships to Vegetation and Climate

Nina Hewitt

Soils are fundamental to life on land. Soils supply water, nitrogen and all of the mineral nutrients (potassium, calcium, etc.) to photosynthetic plants, the base of food webs in terrestrial ecosystems. Soils are the medium in which plants root and gain support, and they host the micro- and macro-biota that break down and cycle organic nutrients in ecosystems. Viewed in profile, one can see distinctive horizontal layers through a soil column, or horizons that reflect the age of the soil and the particular environments in which the soil formed. With some knowledge and a good eye, it is possible to “read” or interpret soil processes based on their visible characteristics.

In this lab we will explore some important soil types in BC, their properties visible in a vertical profile, and the related formational processes. At the end of the lab, you should be able to begin describing and interpreting soils in the field.

Learning Objectives

After completion of this lab, you will be able to:

  • Name and describe most major soil types (orders) present in BC
  • Identify the soil profile characteristics that define these soil orders
  • Name and describe the major mineral horizons and some sub-horizons in soils
  • Visualize a variety of soil profiles and how their properties change with depth
  • Relate soils to climate, biogeoclimatic zones, and parent materials
  • Relate soil profile characteristics such as color, texture and horizon depth to soil processes such as eluviation and organic matter deposition.
  • Work with resources for visualizing and studying soils and ecosystems including Google Earth, UBC’s SoilWeb and ClimateBC websites, BC’s Biogeoclimatic Ecosystem Classification (BEC zone) System, and the Canadian System of Soil Classification (CSSC).

Pre-Readings

BEC zones

BC’s Biogeoclimatic Ecosystem Classification (BEC) system classifies ecosystems according to their major climate types and vegetation associations. On that basis, land cover in BC has been classified into a series of different ecosystem types (BEC zones) including Coastal Western hemlock and Douglas fir Forests near the southern coast, Englemann Spruce-Subalpine Forest and Alpine Tundra in mid- to high-elevation locations of the Coast Mountains, Ponderosa Pine, Interior Douglas fir and Bunchgrass BEC zones in the interior, and more. You may peruse BC’s BEC zone descriptions at Selkirk College’s online modules (hover over the zone name to view the map; click on the zone name to see its description).

Soil Formation and Parent Materials

Soils form in place over periods of time, under the influence of other soil forming factors, climate (heat and moisture), organisms, topography and parent materials.

Parent materials determine the mineral building blocks of most soils, and vary considerably from place to place. They are classified according their mineral characteristics, whether they are bedrock or deposits, and if the latter, the mode of deposition (see https://landscape.soilweb.ca/; esp. colluvial, glacial, lacustrine). Glacial till is important in BC, comprised of varying grain sizes from fine silt and clay to coarser sand, gravel and boulders of mixed lithology (mineral composition). Till often occurs in a sequence of a layer of ablation till overlying more compacted basal or lodgement till.

Modern soil science recognizes that soils are a product, not of “factors”, but of processes acting upon soils, their biota and parent materials. At the most general level, these include additions, losses, transformations, and translocations. More specific key processes include: organic matter decomposition that releases and cycles nutrients, and adds humus (colloidal, decay-resistant organic particles; chemical weathering of minerals to produce fine colloidal silicate clay particles; vertical translocations such as eluviation and illuviation that contribute to horizon formation in rainy climates.

Soil Profiles and Properties

To study soils we use the soil profile, a vertical cross-section, or side-on view, of about 1 metre depth (Figure 9.1).

Figure 9.1. Diagram of a soil profile showing approximate positions of major horizons (organic, O) and mineral (A, B, C). Not all horizons will be present in a particular soil. Figure courtesy of the US Department of Agriculture

Soil profiles are normally described at two levels: (i) in the field, different horizons are identified and described using simple observable properties such as colour and texture (feel method) and (ii) samples taken from each horizon identified are later subjected to detailed physical and chemical analysis in the laboratory. The soil characteristics that can be assessed in the field, and which you may see evidence of in this lab include:

  • Colour, using standardized colour charts.
  • Texture, typically classified using the “feel” of the soil.
  • Structure, i.e., the aggregation of soil particles into units or peds.
  • Miscellaneous special features, such as mottles, roots and pores.

Using these properties, one can identify relatively homogenous horizontal layers or horizons within each soil profile. See Supporting Material, below, for an expanded description of observable features.

Departments of agriculture in different countries have developed slightly different conventional horizon designations. In Canada, major horizons are designated by capital letters. Non-mineral horizons are designated by the letters O, L, F and H; mineral horizons by A, B, C and R). Each major horizon can be given one or more lowercase suffixes (such as e for eluviated, t for clay accumulation, g for gleyed and f for ferric iron in mineral horizons). These suffixes denote sub-horizons of the soil. We will encounter only a subset of these, which you will find described in your textbook. For a complete description of horizons and lowercase suffixes, see CSSC (1998) Chapter 2.

Soil Classification in Canada

The type and combination of horizons (09.PR 3, above) present in the soil is later used to classify the entire profile into a class of soils such as podzols or gleysols. In Canada, we use the Canadian System of Soil Classification (CSSC). The CSSC identifies 10 major soil orders which are subdivided into great groups, subgroups, etc.

Quickly peruse the maps and descriptions of BC’s soil orders at UBC’s SoilWeb’s Classification pages. Pay attention to the soil orders included in this lab, Organic, Podzolic, Brunisolic, Chernozemic and Regosolic. Also skim Cryosolic and Luvisolic, which are relevant to BC and this lab.

We further recommend the following videos on UBC’s SoilWeb:

Lab Exercises

In this lab we will examine landscapes, climate and ecosystem characteristics, and soil profiles for 5 contrasting locations that harbour representative soil types in BC. We will locate the sites using Google Earth imagery and examine the landscapes in terms of topography, elevation and other geographic factors. We will determine climatic conditions for the locations using online climate maps and identify ecosystem characteristics, including dominant vegetation, using standard biogeoclimatic classifications (BEC zones) for the 5 locations. Finally, we will examine the soil profiles of comparable soils using online information and imagery (UBC’s Virtual Soil Monoliths at SoilWeb). The lab consists of 4 exercises and should take 2.5 to 3 hours to complete.

EX1: Understand the Field Locations Where Soils Will Be Examined

Soils reflect the regional geography. The 5 soils we will examine are located in and around Vancouver in southern coastal BC (2 sites), inland and up the Coast Mountains (2 sites), and in BC’s southern interior (1 site). A Google Earth tour has been created to allow you to explore the local landscapes for each of five sites in BC where we will examine soils. It should take you around 20 minutes to complete (3-5 minutes per site). Your knowledge and understanding of concepts presented in this tour will be assessed in the later Lab Exercises.

Step 1: Using your browser, download this KML file, upload and open it in Google Earth Web. Or go to the online link, Soils of BC Instructional Tour.

Step 2: Click “Present” to start the tour (Figure 9.2a). Visit each stop by clicking on the right arrow beside the Table of Contents button (Figure 9.2b).

Figure 9.2a. Figure courtesy of Google Earth
Figure 9.2b. Figure courtesy of Google Earth

At each stop, explore the main window. View the images, read the text and watch any embedded videos in the information panel on the right. You can double-click the images to enlarge them. You can return to any stops using the Table of Contents.

Step 3: Find the elevation for each site (Figure 9.2c). Place your cursor immediately below the place marker for the site in question (e.g. “Site #5: Grasslands and sagebrush soil”). Note the elevation indicated at the bottom right corner of the screen. You will record it in Table 1 in the next Lab Exercise section. Do not confuse the ground level elevation with the camera elevation:

Figure 9.2c. Figure courtesy of Google Earth

EX2: Determine Climate and Biogeoclimatic Ecosystem Classifications (BEC)

In this exercise you will identify and record the BEC zones, climate variables and elevations of selected sites at which we will examine soils. It should take you around 40 minutes to complete.

Table 1 records geographic coordinates, elevation, BEC zone and climate variables for our five sites. Some values have been pre-filled. You will supply the missing values, following the instructions below.

Table 9.1: Location, BEC zone and climate of our five focal sites.
Site Geographic Coords (degrees /minutes/seconds; decimal degrees in brackets) Approx. Elevation (m a.s.l.) BEC Zone (abbr. and full name) Winter Average Temp. (Tave _wt) (°C) Summer Average Temp. (Tave _sn) (°C) Winter Pcpn. (PPT_wt) (mm) Summer Pcpn.

(PPT_sm) (mm)

1: Bog soil 49°08’39″N

122°56’00″W

(49.144, -122.934)

5 CDF, Coastal Douglas fir 3.5 16.7 483 136
2: Coastal  needleleaf forest soil 49°15’49″N

122°33’33″W

49.264, -122.559)

 

 

3: Subalpine forest soil 50°58’29″N

122°46’31″W

(50.975, -122.774)

4: Alpine tundra soil 50°57’59″N

122°47’42″W

(50.966, -122.796)

2,083 IMA, Interior Mountain Heather (within the broader Alpine zone) -7.3 7.4 486 174
5: Interior grassland /scrubland soil 49°05’58″N

119°42’46″W

(49.100, -119.711)

Step 1: Download the Table 1 file to your computer (in Worksheets), open it in a spreadsheet application and determine the information you need to supply (indicated by blank cells).

Step 2: Open the map at Climate BC Website. For each site of interest, enter the latitude and longitude in decimal degrees from Table 1 and hit “Calculate” (Figure 9.3a). A red marker will appear on the map at the specified location. Zoom in using the +/- symbols. Double-check location using landmarks such as roads, rivers or lakes, based on the site’s location in the Google Earth Tour. Once you are in the right place you must manually move the cursor slightly by clicking on an adjacent location to your marker. This action will recalculate elevation correctly (otherwise climate data will be modelled at the elevation in the previous frame, above or below your site!). Click “Calculate” again. To see the base map better, use the slider at the top of the map to increase transparency of the coloured layers.

Step 3: At the top of the map, click on the “BEC zones” overlay button (2nd button from left) and select “BEC zones – currently mapped” from the drop-down menu (Figure 9.3b)

Step 4: Determine site’s BEC zone using the legend along the top of the map (Figure 9.3c) Record the BEC zone abbreviation and full name (you may ignore variant/subzone) in Table 1. You can move the transparency slider at the top of the map to intensify the colour of the BEC zone. If you have trouble differentiating colors, ask a friend or relative to confirm for you.

Step 5: Determine the climate variables for each site of interest. Having entered the correct coordinates manually repositioned the cursor and re-calculated, check the time period displayed in the “Historical” box (Figure 9.3d). The default is “Normal_1961_1990”, which is adequate for our purposes*. Click “Calculate.” Important note: you must click this every time you change any settings in the left sidebar or on the map!

Under “Seasonal Variables” (Figure 9.3d), find the following data for your site:

  • Mean Winter Temperature (Tave_wt=) (shown in degrees Celsius)
  • Mean Summer Temperature (Tave_sm=)
  • Winter Precipitation (PPT_wt=) (shown in millimetres)
  • Summer Precipitation (PPT_sm=).

Enter these data in the blank cells in your Table 1.

Figure 9.3a. Figure courtesy of ClimateBC
Figure 9.3b. Figure courtesy of ClimateBC
Figure 9.3c. Figure courtesy of ClimateBC
Figure 9.3d. Figure courtesy of ClimateBC

*If you choose a more recent period (e.g., “Normal 1981-2010”; “Decade 2001-2010”), temperatures will have increased marginally due to anthropogenic climate change. However, soil formation reflects long term averages occurring over hundreds to thousands of years, so we can safely use the default period.

Step 6: Record the elevation for each site (from the first set of Lab Exercises, Step 3) in Table 1. Some values are pre-filled for you.

Step 7: Submit the data you recorded in Table 1 in a format specified by your instructor.

Step 8: Select another location of your own choice in extreme northern BC, above 58 degrees north latitude, by placing your cursor at your chosen spot and clicking to place a marker. Make a mental note of whether this is a coastal or inland location. Click “Calculate” to update the climate data. Create a new row in your Table 1 and enter the site’s geographic coordinates, BEC zone and climate data as you did for the other sites. You will come back to this site in the last set of Lab Exercises, so you may want to keep this page open with your marker showing.

Step 9: Record and submit your observations of the following in a format specified by your instructor (in one to two paragraphs total):

  • The seasonal temperature and precipitation conditions for the five sites. Rather than repeating the data in Table 1, simply indicate which sites are seasonally wettest and driest, warmest and coldest, etc. Also, note how climate relates to the site’s geographic location in terms of distance inland from the coast* (i.e., is it coastal or interior) and elevation.

* Note: You can determine approximate distance inland from the coast with the measurement tool in the Google Earth tour (first set of Lab Exercises). Click the ruler icon on the left sidebar below the Projects button, position your cursor over your starting point (i.e., the coast) and click; then move the cursor inland, due east, to the site of interest and click again to find the straight-line distance between the points.

  • The types of vegetation (according to BEC zone or information from the Google Earth Tour) at the sites
  • The relationships between BEC zone/vegetation and climatic conditions.

EX3: Describe the Soil Profiles

Now that we have examined the geography, climate variables and BEC zones for the sites, we will examine representative soil profiles for each. Because we do not have available soil pits for our 5 sites, we will substitute equivalent profiles from UBC’s Virtual Soil Monoliths website (Krzic et al. 2010). A representative soil profile for each site has been selected for you from this collection. This exercise should take 45 minutes to complete.

Table 2 records soil profile characteristics of representative soil monoliths for our 5 sites. Some values have been pre-filled. It is available as a downloadable file in which you will supply the missing values, following the instructions below.

Table 9.2: Soil profile characteristics of soil monoliths representative of each site.
Information from Equivalent soil profile about: Bog soil Coastal needleleaf forest soil Subalpine forest soil Alpine tundra soil Interior grassland, scrubland soil
Soil Monolith (label and link) UBC # 6-01 UBC # 7-05 UBC # 1-20 UBC # 8-02 UBC # 2-06
Organic/litter layer (depth) Om (0-13 cm)

Oh (13-42 cm)

– not present – not indicated
A horizon (depth) – not present  

 

Ah (0-5 cm)
B horizon (depth, cm) – not present – not present
C horizon (depth, cm) IIC (42-78 cm) IIC (27-57 cm)

IIIC (57-100 cm)

C (5-59 cm)
Parent Material Lacustrine Colluvium
Descriptive Notes: Observable features, e.g., colours (generally), texture, presence of stones/rocks, mottles, etc. Dark A layer from with visibly undecayed litter; Large pore, roots at 40 cm in Bm layer; Sub-rounded stones frequent below 70 cm; Transitions from A to B; B to C clear; A layers are separated by broken transition
Soil Order Organic Brunisol Regosol
Soil Great Group Humisol Dystric Brunisol Regosol

Step 1: Download the Table 2 file to your computer (in Worksheets), open it in a word processing application, and determine the information you need to supply (indicated by blank cells).

Step 2: Follow the links in Table 2 to view the soil monoliths representative of soils at each site. For each monolith, you will find information about the soil including the order, great group, and horizon labels and associated depths for different layers of the soil that were identified by UBC soil scientists.

Step 3: Supply the missing information in Table 2 for each soil including organic layer label and depth; A, B and C horizon labels and depth, if applicable; parent material type; soil order and great group name. Some information has been pre-filled for you.

Step 4: On the soil monolith pages, click the bottom of the soil and then click again on the figure (“+” symbol) to enlarge. Examine the image to expand upon the information about each soil. Look for characteristics such as:

  • Obvious visible features such as strong colours (e.g., black indicates presence of organic matter; reddish/orange indicate presence of iron oxides)
  • Mottles (visible blotches on the face of the profile – though these are not particularly evident in these dry monoliths)
  • Large fragments, stones or boulders, and their frequency and shape
  • Distinctness and form of the lower boundary of each mineral horizon (A, B, if present). Use the terminology and diagrams in the Supporting Material that best correspond with what you see in the image (e.g., gradual/abrupt; smooth/wavy)
  • Other properties to which you may wish to refer later, such as the thickness of the A or B horizon; lowercase suffix labels indicative of important properties, etc.

Enter your observations in point form in the Descriptive Notes row of Table 2 (see the pre-filled cell for an example). Your notes need not be exhaustive, but should simply highlight notable visible features (choose 2-4 features for each soil).

*Note We recommend you take screenshots, or save the monolith photos to desktop (right click on the enlarged image/press your computer trackpad with 2 fingers, click “save image as”, save it to your computer as a .jpg file) for later reference (e.g., to answer questions about soils in 09.EX4).

Step 5: Submit the data you recorded in Table 2.

EX4: Explore Soil Profile Characteristics and Underlying Processes

In this exercise you will apply and extend the knowledge acquired in the preceding exercises to explore soil profile characteristics and underlying processes in different contexts. It should take you 20 minutes to answer these questions.

  1. Figure 9.4, below, shows an Organic soil from British Columbia. Possible horizon labels have been indicated, but these are tentative, based on the information provided in the image. Compare this soil with the one listed for Site #1 (horizon layers and its monolith at: 6-01 TerricHumisol.jpg) and provide answer to the following:
    1. Comment briefly on similarities (or differences, if present) between the profiles and
    2. Explain why both these soils have no A or B horizons. (2-3 sentences).
Figure 9.4. Soil pit in an Organic soil from BC (great group: Mesisol). The measuring stick is divided into 10 cm units. Note that the sub-horizon label “m” has a different meaning when used in combination with the Organic layer than with mineral (A, B or C) horizons, and is short for “mesic material” (see CSSC, Chap 2, Organic Horizons, Om). Figure courtesy of the Soil Working Group (Government of Canada)
  1. Figure 9.5 is an image of a podzol from Quebec. Drawing on information learned in lecture, this lab and your text, suggest appropriate names for the following layers, including major horizon and lowercase suffixes, and describe the processes responsible.
    1. The light-coloured layer at 4-7 cm: _________. Specific process(es) responsible (1-2 sentences).
    2. The reddish/orange layer at 10-20 cm: _________. Specific process(es) responsible (1-2 sentences).
Figure 9.5. Podzolic soil from Quebec on sandy parent materials. Figure courtesy of the Soil Working Group (Government of Canada)

Gleying is a process in which metals in the soil such as iron (and sometimes manganese) are reduced, producing blue-grey colours in soils, often with mottling (Figure 6). When oxygen is present, iron is oxidized and has a reddish colour. When, under situations of periodic water-logging from, e.g., a seasonally raised water table, oxygen is depleted, the iron is reduced and takes on a blue-grey hue.

Figure 9.6b. Soil ped with mottles showing presence of both oxidized iron (orange colors) and reduced (blueish) iron minerals. The latter are gley colors. Photograph courtesy of R Weil
Figure 9.6a. A sandy soil with gleyed horizons below about 1 foot depth, where blue-grey colors (indicative of iron reduction) are present amid orange-red (oxidation) mottles. Photo courtesy of Agriculture and Agri-Food Canada

 

 

  1. Explain why you might expect to see evidence of gleying (mottles, blue-grey colours) about 2 feet below the soil surface at Site #2 in Malcolm Knapp UBC Research Forest (1-2 sentences). Hint: Consider the parent materials at this site, as discussed in the instructional video from the Google Earth tour (Video transcript: [Word] [ODT] [PDF]), and in the pre-reading video about the Podzol at Malcolm Knapp forest.
  2. Using their monoliths and your descriptions in Table 2, compare the soil profiles at Site #2, Malcolm Knapp forest and Site #3, Subalpine forest. In particular:
  3. Note any differences in the A and B horizon properties (thickness, colour, features evident from the sub-horizon labels). You may wish to define the Bm horizon, a diagnostic (distinguishing) horizon in Brunisols such as the Site #3 soil.
  4. Given that both sites have coniferous vegetation, account for the differences between them (1-2 sentences for each of a and b).
  5. The Regosol at Site #4 (Alpine tundra) is hardly a soil. Just below, in the valley to the northwest, is a lush meadow (Figure 9.7); and you may wish to view video footage of the valley.  This meadow is also located in the alpine zone. A possible alpine meadow soil profile for an alpine meadow is shown in Figure 9.8.

 

Figure 9.7. Screenshot of Google Earth tour at Site #4 location. Figure courtesy of Google Earth Web

 

Figure 9.8. Soil pit in a Brunisol soil (sombric brunisol) from an alpine meadow. Photo courtesy of University of Calgary
  1. How would you expect the soil in Figure 8 to differ from the Regosol at Site #4? Specifically, describe 2 characteristics that might differ and briefly explain what about the meadow site might account for these differences relative to the scree slope soil (2-3 sentences).

*Hint: The information panel in Site #4 of the Google Earth Instructional Tour suggested that you “Read more about the soils associated with this BEC zone unit at Selkirk College’s online modules.” (See 4th paragraph in the Introduction).

  1. For the northern BC location you chose in the second set of Lab Exercieses, Step 8, predict the sort of soil you might expect to find. Pay attention to climate, BEC zone and soil formation processes. Suggest an appropriate order and indicate why you chose it. Note: it may be a soil order you have not yet described, so use your text or other resources to help you name and describe it. (1 paragraph stating the soil order, the soil’s major characteristics and why you would expect the soil here to fall into this order).

Reflection Questions

  1. In Exercise 1 we examined the vegetation types at each site and explored how climate parameters were associated with BEC Zone. Yet the vegetation at Site #1 (Burns Bog) did not relate clearly to its climate or BEC zone. Briefly explain why this would be, and the implications for the soils found there. (1-2 sentences).

BONUS: At Site #1, the bog soil, imagine that you dug down to layers deposited 7,000-8,000 years ago and found a mysterious layer of fine mineral material. How might you account for that? Hint: This layer was deposited on top of the soil; watch this video of Kent Watson (Thompson Rivers U) and Dr. Art Bomke (UBC Land and Food Systems) interpreting an organic soil along the Coquihalla Highway just north of Merritt, BC, (just first 9 minutes). (1-2 sentences).

  1. The Podzolic soil order has over 50 different soil monoliths in the UBC SoilWeb site, more than any other soil order (Luvisols and Brunisols are 2nd and 3rd respectively). View this distribution map of the Podzols in Canada to appreciate why. Provide 2 reasons to explain why Podzols are so common in BC (2-3 sentences).
  2. The BEC zone identified for Site #5 (Similkameen River environs) occurs in close proximity to 2 contrasting BEC zones. Find these zones by returning to our Site #5 location on the BEC zone map on the ClimateBC_Map website, i) choose and name one of them (just major zone label), ii) suggest the type of soil (by order name) you might expect it to be associated with, and iii) indicate how it might differ from the soil at Site #5 (identify one main difference that refers to the characteristics of the soil profile itself, e.g., depth, color of A horizon, presence of particular sub-horizon layers, etc.). Refer to information in Selkirk College’s online modules and perhaps view sample monoliths of your chosen soil order at UBC Soilweb to assist you.

Worksheets

Lab 9 Table 1

Lab 9 Table 2

Supporting Material

Observable Features Used in the Field Description of Soils

In addition to labelling the major horizons and their lowercase suffixes, several soil properties are typically noted during field descriptions of soils.

Colour

For this, a series of standardized “Munsell” soil colour charts is employed. Each page comprises a separate “hue” and is given a letter and number designation (e.g., 7.5YR). Separate colour chips are arranged on each page of the chart on a vertical axis of darkness called a “value” and a horizontal axis of colour intensity called a “chroma”. A particular value and chroma combination is indicated by two numbers as such: 5/2. One of more colour chips are also given verbal descriptions, and a complete colour description of the soil uses both the verbal and numerical descriptions, e.g., 7.5YR 5/2 Brown. To use the colour charts, a moist (or both a dry and a moist) sample of the soil on the fingertip is compared with chips through the holes in the chart until a match is found (NB: when using the charts, it is necessary to be careful not to dirty the chips – the books cost over $ 100 each!). A demonstration of color determination in the field led by Dr. Pennock of U Saskatchewan, is available here.

Texture

Texture conventionally refers to soil particles smaller than 2mm in diameter, which are separated into three textural classes:

Sand: 2 mm to 0.05mm

Silt: 0.05 mm to 0.002 mm

Clay: < 0.002 mm

Clay tends to feel greasy and untextured, silt slightly textured, and sand definitively so. By expressing the proportions (by weight) of each textural class as a %, the textural mix of any soil can be placed on a triangular diagram, and the diagram zoned into types that are given a name (see soil texture triangle in your text or lecture notes). With practice, it is usually possible to place a soil into one of these types with reasonable accuracy using only feel.

Structure

This refers to the aggregation of individual soil particles into units called “peds”. The five structural types that have been distinguished by soil scientists but include “granular” or “crumb”, “platy”, “angular blocky”, “subangular blocky” and “prism-like” (see diagrams in your text or other instructional materials). In addition, a “structureless” class is recognized when soil particles show no aggregation (such as a recent sand deposit). Each structural type is also separated into three size classes (fine, medium, coarse) as defined by the diameter of the peds. A description of the ped uses both the shape and size designations, e.g., “coarse granular” or “medium subangular blocky” structure.

Miscellaneous Features

These include any other obvious features that can be seen in the soil horizon. Some of the most common features that are commented upon include:

  • Mottles and concretions
  • Roots and pores
  • Presence of coarse fragments > 2mm in diameter (e.g., gravel, stones)

For each of the above, the size abundance should be noted.

Horizon Boundaries

In a soil description, the distinctness and form of the lower horizon boundary is also indicated as follows:

Distinctness: The transition to the next horizon, at the boundary is:

Abrupt:  < 3 cm wide

Clear: 3-6 cm wide

Gradual: 6-12 cm wide

Diffuse: > 12 cm wide

Form:

Smooth
Wavy
Irregular
Broken

Attributions

Canadian Society of Soil Science. 2020. Soils of Canada. [Online] Available: https://soilsofcanada.ca/, Accessed June 18, 2020.

Krzic M., R. Strivelli, E. Holmes, and S. Dyanatkar. 2010. Virtual Soil Monolith Collection at UBC. The University of British Columbia, Vancouver. [Online] Available at: https://monoliths.soilweb.ca/, Accessed June 15, 2020.

Min. of Advanced Ed. 2004. Selkirk College Online BEC Training Modules, Biogeoclimatic Ecosystem Classification System in BC. [Online] Available at: https://selkirk.ca/discover/bec/zones/zones.html, Accessed June 21, 2020.

Soil Classification Working Group. 1998. The Canadian System of Soil Classification, 3rd ed. Agriculture and Agri-Food Canada Publication 1646, 187 pp. ISBN 0-660-17404-9. [Online] Available at: http://sis.agr.gc.ca/cansis/taxa/cssc3/index.html  Accessed June 21, 2020.

University of British Columbia. 2019. ClimateBC Map. [Online] Available at: http://www.climatewna.com/ClimateBC_Map.aspx. Accessed June 21, 2020.

Media Attributions