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Examine two of the natural processes which influence soil formation. - Leaving Cert Geography - Question 17 - 2008
Question 17
Examine two of the natural processes which influence soil formation.
Worked Solution & Example Answer:Examine two of the natural processes which influence soil formation. - Leaving Cert Geography - Question 17 - 2008
Step 1
Natural Process 1: Weathering
Answer
Weathering is the physical and chemical breakdown of rocks at the Earth's surface which plays a fundamental role in soil formation. There are two main types of weathering:
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Physical Weathering: This involves the mechanical breakdown of rocks without changing their chemical composition. Factors such as temperature changes, water freeze-thaw cycles, and abrasion can cause rocks to fracture and break into smaller particles. These smaller fragments then become a part of the soil profile.
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Chemical Weathering: This process involves the alteration of the chemical structure of the minerals within rocks, often due to interactions with water and atmospheric gases. For example, the reaction of carbon dioxide with water creates carbonic acid, which can dissolve carbonate minerals, liberating essential nutrients like calcium and magnesium into the soil, contributing to its fertility.
Step 2
Natural Process 2: Organic Matter Accumulation
Answer
The accumulation of organic matter is another crucial process influencing soil formation. Organic matter, which includes decomposed leaves, plant material, and animal remains, enriches the soil and impacts its structure and fertility.
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Decomposition: As plants and animals die, their remains are broken down by microorganisms such as bacteria and fungi. This decomposition enriches the soil with organic compounds and nutrients vital for plant growth. The presence of humus, a stable organic matter, enhances soil structure and moisture retention.
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Soil Horizons Development: The incorporation of organic matter leads to the formation of distinct soil horizons. The O horizon (organic layer) and the A horizon (topsoil) are vital components of a healthy soil ecosystem, facilitating water retention, nutrient exchange, and microbial activity, all of which are essential for sustainable agriculture.