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An agricultural science student wanted to determine the amount of organic matter present in a soil sample - Leaving Cert Agricultural Science - Question 1 - 2022
Question 1
An agricultural science student wanted to determine the amount of organic matter present in a soil sample. (i) Explain the underlined term. (ii) Briefly describe o... show full transcript
Worked Solution & Example Answer:An agricultural science student wanted to determine the amount of organic matter present in a soil sample - Leaving Cert Agricultural Science - Question 1 - 2022
Step 1
Explain the underlined term.
Answer
Organic matter refers to the remains of plants and animals (and microorganisms at various stages of decomposition) as well as the living components of soils. It plays a critical role in soil health, enhancing nutrient availability, and improving soil structure.
Step 2
Briefly describe one advantage of the presence of organic matter in a soil.
Answer
One advantage of organic matter in soil is that it improves soil structure. This aids in water percolation and root penetration, which enhances water-holding capacity. Improved soil structure allows for better plant growth and movement of nutrients within the soil.
Step 3
Describe how the student determined the % organic matter in the soil sample.
Answer
To determine the percentage of organic matter, the student performed the following steps:
- Weighed an empty crucible and recorded its weight.
- Weighed the soil sample and recorded this weight as well.
- Burned the soil sample in the crucible using a Bunsen burner, ensuring it was completely combusted, until no more smoke was produced.
- Weighed the crucible again with the burnt residue.
- Calculated the % organic matter using the formula: ext{% Organic Matter} = \frac{\text{Soil mass last after burning}}{\text{Soil mass before burning}} \times 100