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2. (a) List four factors that are responsible for the development of soil structure - Leaving Cert Agricultural Science - Question 2 - 2010
Question 2
2. (a) List four factors that are responsible for the development of soil structure. (b) Outline the formation of peat bogs in Ireland. (c) Describe an experim... show full transcript
Worked Solution & Example Answer:2. (a) List four factors that are responsible for the development of soil structure - Leaving Cert Agricultural Science - Question 2 - 2010
Step 1
List four factors that are responsible for the development of soil structure.
Answer
- Wetting and Drying: The expansion and contraction of soil particles due to moisture changes contribute to the aggregation of soil particles.
- Activity of Soil Animals: Organisms like earthworms and insects aerate the soil, leading to improved structure.
- Freezing and Thawing: The freeze-thaw cycle creates cracks and breaks in the soil, promoting structure development.
- Root Activity: Plant roots penetrate the soil and help in binding particles together, enhancing soil structure.
Step 2
Outline the formation of peat bogs in Ireland.
Answer
Peat bogs in Ireland are primarily formed due to heavy local rainfall, which leads to waterlogging and the accumulation of organic material, particularly sphagnum moss.
Initially, stagnant water bodies provide a suitable environment for the growth of this moss, which accumulates over time, creating a thick layer of peat.
The anaerobic conditions within the waterlogged environment prevent the complete decomposition of plant material, allowing peat to build up.
Factors like leaching of nutrients and the absence of drainage further contribute to the formation.
Step 3
Describe an experiment to estimate the percentage organic matter in a soil sample.
Answer
To estimate the percentage of organic matter in a soil sample, first, weigh the dry soil sample.
Then, place the sample in a crucible and burn it over a Bunsen burner until all the organic matter is combusted, which typically leaves behind only the inorganic residue.
After cooling, weigh the remaining ash.
Calculate the percentage of organic matter using the formula:
ext{Percentage Organic Matter} = rac{( ext{Weight of Soil Sample} - ext{Weight of Ash})}{ ext{Weight of Soil Sample}} imes 100
This method provides a reliable estimation of the organic content in the soil.