LO 2.0 - 2.3 Investigate Soil Profiles and Summarise Soil Groups

Question 1

Question

What do we mean by Soil Profile?

Three points.

Soil Profiles and Soil Groups

Answer 1

Soil profiles
* Different layers can often be seen in soil as you dig downwards.
* The different layers are known as horizons, and the horizons together make up the soil profile.
* The soil profile includes the deeper layers down to the unaltered parent material on which the soil has formed.

Soil Profiles and Soil Groups

Question 2

Question

What is Eluviation in relation to Soil Profile?

Soil Profiles and Soil Groups

Answer 2

Eluviation :
The movement of material in suspension down through the profile.

eluvial horizon.

Soil Profiles and Soil Groups

Question 3

Question

What is Illuviation in relation to Soil Profile?

Soil Profiles and Soil Groups

Answer 3

Illuviation :
The deposition of material in suspension lower down in the profile.

Illuvial horizon

Soil Profiles and Soil Groups

Question 4

Question

Major classification of soil horizons?

All the letters.

Soil Profiles and Soil Groups

Answer 4

Soil Horizons
* O - Organic
* A - Organic & Mineral mixed
* E - Depleted of material
* B - Clay and minerals
* C - Parent material, ie,. stones and rocks.
* R - Bedrock

Soil Profiles and Soil Groups

Question 5

Question

What is the O horizon in soil?

Soil Profiles and Soil Groups

Answer 5

O Horizon:
May or may not be present. Organic matter – fresh leaf litter at the surface, more decomposed at deeper levels.

Soil Profiles and Soil Groups

Question 6

Question

What is the A horizon in soil?

Soil Profiles and Soil Groups

Answer 6

A Horizon:
Roughly corresponds to topsoil. Beginning of true mineral soil level. Consists of organic matter mixed with inorganic, weathered material. Dark in colour due to presence of organic matter.

Soil Profiles and Soil Groups

Question 7

Question

What is the E horizon in soil?

Soil Profiles and Soil Groups

Answer 7

E Horizon:
May or may not be present. Light coloured horizon, eluviation is the major process at this layer. In coniferous forests, this layer often has an ashy-grey colour.

Soil Profiles and Soil Groups

Question 8

Question

What is the B horizon in soil?

Soil Profiles and Soil Groups

Answer 8

B Horizon:
This is the subsoil. In this horizon, illuviation is the major process. In areas of high rainfall, the B horizon will be found low in the soil profile, whereas in drier areas it will be closer to the surface. The B horizon is often lighter in colour than the A as there is little or no organic matter present, although it may be darker if iron has been leached from the A horizon above (and it may also appear darker if it is wetter).

Soil Profiles and Soil Groups

Question 9

Question

What is the C horizon in soil?

Soil Profiles and Soil Groups

Answer 9

C Horizon:
Is made up of unconsolidated parent material – fragments of rock of varying sizes. This may be residual (ie it has formed in situ from the bedrock below) or it may have been transported to its present location.

Soil Profiles and Soil Groups

Question 10

Question

What is the R horizon in soil?

Soil Profiles and Soil Groups

Answer 10

R Horizon:
The R horizon is the consolidated (solid) bedrock.

Soil Profiles and Soil Groups

Question 11

Question

Great Soil Groups
Soils in Ireland are classified into eleven groups, roughly corresponding to their topographical position and the underlying geology.

How many can you name?

Soil Profiles and Soil Groups

Answer 11

Great Soil Groups
* Lithosol
* Podzol
* Grey Brown Podzolic
* Brown Earth
* Ground Water Gley
* Surface Water Gley
* Basin Peat
* Blanket Peats
* Brown Podzolics
* Rendzina
* Regosols (Alluvium)

Soil Profiles and Soil Groups

Question 12

Question

What are Lithosol Soils?

Soil Profiles and Soil Groups

Answer 12

Lithosols
The **shallow stony soils **on parts of the Burren and in high mountain areas are classified as Lithosols. They have a very limited potential for agriculture due to depth limitations and can be used only for extensive grazing.

Soil Profiles and Soil Groups

Question 13

Question

What are Podzol Soils?

Soil Profiles and Soil Groups

Answer 13

Podzol Soils
Podzols are soils which occur in association with blanket peats and often have a thin layer of peat on the surface. These soils are developed in cold, wet and acidic conditions, and are typically covered with a heather moor or coniferous forest stand.

Soil Profiles and Soil Groups

Question 14

Question

What are Grey Brown Podzolics?

Soil Profiles and Soil Groups

Answer 14

Grey Brown Podzolics
Are formed over limestone glacial drift which have heavy subsoil and can be excellent agricultural soils. They are widespread in the Midlands and east of Ireland, where they are used for the production of a wide range of crops. Being formed over limestone they usually **do not require as much lime **as other soils.

Soil Profiles and Soil Groups

Question 15

Question

What are Brown Earths?

Soil Profiles and Soil Groups

Answer 15

Brown Earths
Are similar to the Brown Podzolics except that the movement of iron and other soluble constituents have not taken place to the same extent. This may be due to lower rainfall or different soil parent material. The profile is uniform with no obivous distinct horizontal development. These soils have not been extensively leached or degraded.

Soil Profiles and Soil Groups

Question 16

Question

What are Ground Water Gleys?

Soil Profiles and Soil Groups

Answer 16

Ground Water Gleys
Gleys are soils where the effects of drainage impedance dominate and which have developed under the infulence of permanent or intermittent waterlogging. Gleys are soils with impeded drainage. This may be due to their occurrence in a low position where there is a high water-table, or to their heavy nature which prevents water from moving quickly through them.

Soil Profiles and Soil Groups

Question 17

Question

What are Surface Water Gleys?

Soil Profiles and Soil Groups

Answer 17

Surface Water Gleys
(SWG) are soils that are poorly drained due to a slowly permeable subsurface layer. This layer slows down the movement of water through the soil to such and extent that the water backs up and causes water-logging of the top 40cm for prolonged periods of the year.

Soil Profiles and Soil Groups

Question 18

Question

What are Basin Peats?

Soil Profiles and Soil Groups

Answer 18

Basin Peats
Occur extensively in the midlands in hollows and in flat poorly drained areas. They result from an accumlation of layers of sphagnum moss which have kept growing until the surface of these bogs is frequently above the level of the surrounding land. This is why they tend to be deeper than blanket peats and are often called raised bogs.

Soil Profiles and Soil Groups

Question 19

Question

What are Blanket Peats?

Soil Profiles and Soil Groups

Answer 19

Blanket Peats
Occur mainly in the west of Ireland or at high elevations, e.g., Wicklow mountains. Although they can be serveral meters deep, their surface configuration is closely related to the underlying soil base and they therefore cover the landscape like a blanket - hence the name Blanket Peat or Blanket Bog. Because they are composed almost entirely of organic matter, they hold large quantities of water. They are very difficult to drain and have low agricultural value and are vulnerable to overgrazing.

Soil Profiles and Soil Groups

Question 20

Question

What are Brown Podzolics?

Soil Profiles and Soil Groups

Answer 20

Brown Podzolics
These soils have a reddish - brown B horizon indicating that some iron has been leached downwards throught the profile. It occurs in lower rain fall areas than the Podzols and is a better agricultural soil. It usually need lime and fertilisers but is suitable for a wide range of agricultural enterprises.

Soil Profiles and Soil Groups

Question 21

Question

What are Rendzinas?

Soil Profiles and Soil Groups

Answer 21

Rendzinas
These soils have a high pH (>pH 7). They can be very stony, as a result of weathering of rock material close to the surface. Where deep enough, they are valuable agricultural soils and can be used for a wide range of crops. They do not occur extensively in Ireland but are found in parts of Counties Sligo, Cavan, Galway and Limerick.

Soil Profiles and Soil Groups

Question 22

Question

What are Regosols?

Soil Profiles and Soil Groups

Answer 22

Regosols
They are formed from river and lake deposits where there has not been enough time to develop distinct horizons. Regosol profiles show no distinct horizon development. The texture of these soils can vary between sands and clays, depending on the material from which they are derived. They may be acid or alkaline for the same reason.

Soil Profiles and Soil Groups