Chapter One - Soils of Ireland Flashcards
How many soil types are in Ireland?
450
- Select the only ONE correct statement from the following options?
Irish soils range in age from what?
Answer is C) Counties in the northern part of Ireland tend to have soils of approximately 6,000 - 7000 years old while in the south they are estimated to be 15,000 + years old
What is a Soil?
The surface layer of the Earth’s crust which is capable of supporting life. They originate from rocks. They can be 10+ metres deep in the south midlands to a few centimetres on some drumlins in the northern counties to even a few millimetres on elevated slopes.
Our soils have formed through weathering of geological materials (solid rock, glacial drift, alluvum (river flooding deposits) or windblown deposits.
- Soils have been formed through weathering of geological materials or windblown deposits.
Is the above statement
A) True
B) False
True
- List the seven factors affecting soil formation?
- The parent material from which the soil is forming.
- Weathering
- The type of landscape or topography where the soil is forming.
- Climate. Temperature changes - expansion causing stresses.
- Influence of living things such as plants including: Trees, fungi, bacteria, viruses, animals, insects, etc.
- Time
- Influence of humans.
- List TWO factors that affect the physical weathering process in soil formation?
Changes in temperature.
Frost.
Wetting and drying.
Erosion by water and wind.
What is Parent material?
The soils derived from the variety of rock types from which they are formed. Parent material material can be glacial or solid bedrock.
Most soils in Ireland are derived from glacial deposits.
What is weathering?
The process by which rocks are broken down into smaller and smaller pieces.
What is Erosion?
The process by which rock particles and soil are moved. Water and wind are the main causes of erosion.
What are rocks made up of?
Minerals
What are the 3 types of rock?
1.Igneous.
2. Sedimentary.
3. Metamorphic.
What is Igneous rock?
Formed from hot molten lava whih made up the earth’s crust millions of years ago. The minerals in these rocks are mostly in the form of crystals and are the primary source of minerals found in all our soils.
Igneous rocks are very hard and weather slowly.
The main igneous rocks are basalt, (Antrim plateau, Giants Causeway) and Granite (wIcklow Mountains, Cnnemara, Mourne and Slieve Gullion, Donegal)
Sedimentary - Derived from weathered material (fragments of rocks, lay, silt and sand) and deposited by water and wind. These sediments later become compressed by more material on top and cemented to form new rocks such as sandstones, shale (compressed clay) and limestone (formed from shells) nd skeletons of marine animals of various sizes)
Metamorphic Rocks - Formed fromigneous or sedimentary rocks which have been altered or changed by extreme pressures and temperatures associated with movements and fracturing in the earth’s crust or the effect of huge depths or rock on underlying rock over a very long period of time. Slate is formed from shales, quarts from sandstone and marble from limestone.
What are the three types of Weathering
Physical weathering - Parent rock materials are broken down into finer particles by changes in temperature, frost, wetting and drying and erosion by water and wind.
Chemical Weathering - The parent rock materials are broken down through chemical reaction. Carbon Dioxide in the air dissolves in rainwater forming a weak solution of carbonic acid. When acid comes in contact with rock it steadily wears down them away
Biological weathering is attributable to organisms which fragment materials by both chemical and physical means. Plants produce Carbon Dioxide which combines with water to form carbonic acid. Roots of plants penetrate cracks in the rock and as they grow thicker apply pressure which further opens the cracks.
What is Leaching?
The dominant soil forming process in Ireland. It is the movement of water down through the soil. It dissolves and removes various constituents gradually making the soil more acidic.
It differs depending on rainfall. Increases with more rainfall and is responsible for the differences between Irish soils eg blanket bogs in West of Ireland where rain fall is very heavy are acidic.
Topography
Slope of the ground. Weathered soils tend to erode from steep slopes and build up on flatter land at the bottom. Level land is more likely to produce uniform weathering.
What’s a soil profile?
A vertical section cut of soil. The vertical section of these layers is called a soil profile. The different layers are called horizons.
Image of different rocks
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See image of Lithosols, Podzols, Grey Brown Podzolics and Brown Earths:
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Insert image of Ground Water Gleys, Surface Water Gleys, Basin Peats, Blanket Peats, Brown Podzolics, Rendzinas, Regosols.
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What are Soil particles and pores?
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What is Water Capacity?
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What is Aeration?
What does Nutrient holding capacity depend on?
What is Stability?
What is Electric Charges?
What is Organic Matter?
