Observe the experimental set-ups A and B in which 120ml of water was made to drain through each of the different soils contained in the funnels.
Use the experimental set-ups to answer Questions (a) – (d).
(a) State the volume of water collected in each of the measuring cylinders in setups A and B.
(b) Calculate the volume of water retained in each of the set-ups A and B.
(c) Calculate the percentage of:
(i) water which percolated through each of the soils in set-ups A and B
(ii) water retained in each of the soils in set-ups A and B.
(d) Which one of the soils in set-ups A and B will be better for crop production? Give three reasons for your answer.
Explanation
(a) Volume of water collected in set-up A= x ml, Volume of water collected in Set-Up B = yml
(b) Volume of water retained in A = 120ml - xml = pml
Volume of water retained in B = 120ml - yml = qml
(c)(i) Percentage of water which percolated through A
= \(\frac{xml}{120ml} \times \frac{100}{1}\) = R%
Percentage of water which percolated through B
= \(\frac{yml}{120ml} \times \frac{100}{1}\) = S%
(ii) Percentage of water retained in A
\(\frac{pml}{120ml} \times \frac{100}{1}\) = U%
Percentage of water retained in B
\(\frac{qml}{120ml} \times \frac{100}{1}\) = V%
(d) Soil in set-up A will be better for crop production.
Reasons;
- Contains O.M. not present or sparse in B
- The O.M. binds soil particles and improves soil structure in A
- Moderate air space/porosity
- O.M. is a source of nutrients for plant growth
- The rate of leaching of nutrients in Ais lower in A than B
- Soil in set-up A has a greater capacity for regulating soil acidity
- Regulates soil temperature better
- Likely to contain more microbes involved in mineralization
- Retains water better than B.