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(a) Explain why regular liming of land is an important farming operation in Ireland - Leaving Cert Agricultural Science - Question 2 - 2006
Question 2
(a) Explain why regular liming of land is an important farming operation in Ireland. (b) List the main steps in the podzolisation of a soil. (c) Outline the chemic... show full transcript
Worked Solution & Example Answer:(a) Explain why regular liming of land is an important farming operation in Ireland - Leaving Cert Agricultural Science - Question 2 - 2006
Step 1
Explain why regular liming of land is an important farming operation in Ireland.
Answer
Regular liming of land in Ireland is crucial for maintaining soil health and crop productivity. This process replenishes essential calcium ions which many soils lack due to their acidic nature. Liming helps to neutralize soil acidity, which improves pH levels, making the soil more hospitable for crops. Moreover, it enhances soil structure by promoting flocculation, which prevents soil compaction and improves aeration. Liming also stimulates microbial activity, which is vital for nutrient cycling, and increases the availability of key nutrients such as phosphorus (P) and potassium (K). Furthermore, it helps mitigate the negative effects of excessive rainfall, which can lead to soil leaching. Overall, regular liming supports sustainable farming practices in Ireland.
Step 2
List the main steps in the podzolisation of a soil.
Answer
- Leaching: The removal of soluble materials and minerals due to rainfall and water movement.
- Accumulation of Iron and Aluminum: The leached materials accumulate in lower soil horizons, forming a hardpan.
- Formation of the Iron Pan: Iron oxides precipitate, creating a distinct layer that inhibits drainage.
- Anaerobic Conditions: Waterlogged conditions develop, leading to further soil changes.
- Accumulation of Organic Matter: Organic materials, like peat, accumulate, contributing to soil structure.
Step 3
Outline the chemical exchanges that would occur in the soil between the lime, soil colloids and soil solution following the application of lime.
Answer
Upon application of lime (CaCO₃ or MgCO₃), chemical exchanges initiate some key reactions in the soil. Lime reacts with the hydrogen ions (H⁺) in the soil colloids, resulting in the replacement of these ions with calcium (Ca²⁺) or magnesium (Mg²⁺) ions. This process leads to a reduction in the acidity of the soil solution, which enhances the availability of nutrients. The calcium ions also encourage the flocculation of soil colloids, improving soil structure and water retention. Moreover, this reaction alters the cation exchange capacity (CEC) of the soil, further promoting nutrient retention.
Step 4
Describe the influence of earthworm activity on the structure and development of a soil.
Answer
Earthworm activity significantly influences soil structure and development in several ways. Firstly, earthworms aerate the soil by burrowing, which enhances water infiltration and reduces compaction. This aeration promotes root growth and improves the overall health of the ecosystem. Secondly, earthworms break down organic matter, incorporating it into the soil and creating nutrient-rich castings that boost soil fertility. Their activities also help in mixing soil layers, which enhances the homogeneity of the soil profile, allowing for better moisture retention and root accessibility. Furthermore, the passage of earthworms contributes to the development of soil aggregates, which improves soil structure, leading to enhanced drainage and root penetration. Overall, the presence and activities of earthworms are vital for promoting a healthy and productive soil environment.