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Calcium is an important element in plant growth - Leaving Cert Agricultural Science - Question 3 - 2010
Question 3
Calcium is an important element in plant growth. (i) Outline one source of calcium for plants. (ii) Describe two processes by which calcium becomes available to pl... show full transcript
Worked Solution & Example Answer:Calcium is an important element in plant growth - Leaving Cert Agricultural Science - Question 3 - 2010
Step 1
Step 2
Describe two processes by which calcium becomes available to plants.
Answer
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Weathering of Limestone: Calcium is released from limestone (calcium carbonate) through the weathering process. As limestone dissolves in the presence of rainwater, calcium ions are made available in the soil, which plants can then absorb through their roots.
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Cation Exchange: Calcium can also be made available to plants through cation exchange processes in the soil. Soil particles hold positively charged ions (cations) like calcium. As plants uptake other cations like potassium, it creates space for calcium ions to exchange and become available to the plant.
Step 3
Explain the underlined terms.
Answer
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Parasitic Disease: Hoose is defined as a disease caused by parasitic organisms such as lungworms or nematodes. These parasites thrive at the expense of the host, impairing its health.
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Deficiency Disease: Grass-tetany is caused by a deficiency of magnesium in the diet of livestock. This illness occurs when the magnesium level in grass is too low to meet the dietary needs of grazing animals.
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Cause for Hoose: The cause is often linked to the presence of lungworm/dictyocaulus or nematodes in the animal.
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Symptom for Hoose: Symptoms include coughing and failure to thrive.
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Control/Treatment for Hoose: Control measures may include vaccinating against parasites and managing pasture to reduce infection rate.
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Cause for Grass-Tetany: The cause is related to low magnesium levels in spring grass, often exacerbated by the use of fertilisers.
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Symptom for Grass-Tetany: Symptoms may include twitching and nervousness in affected animals.
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Control/Treatment for Grass-Tetany: Treatment involves supplementing the diet with magnesium-rich feed or administering magnesium injections.
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Step 4
Give three reasons for a low rate of seedling establishment in a spring-sown crop.
Answer
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Poor Weather Conditions: Adverse weather, such as drought or excessive rainfall, can hinder seed germination and seedling establishment.
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Soil Quality Issues: Poor soil conditions, including compaction or nutrient deficiencies, can severely limit a seed's ability to establish roots effectively.
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Pest Infestation: The presence of pests or diseases like damping off can damage seedlings, resulting in lower survival rates.