Question 2
Take a sample each of specimens F, G, H and rub each between the thumb and forefinger. Put a sample of each of the specimens on your palm and add a little amount of water sufficient to wet it. Mix each sample with the water. Attempt producing a roll and then a ring.
(a) Tabulate your observation from the experiment. (6 marks)
(b) Name two crops that can be grown on specimen H. (2 marks)
(c) (i) Which of specimens F, G and H is preferred for maize production? (1 mark)
(ii) Give three reasons for your answer in 2(c)(i) (3 marks)
(d) State three ways in which specimen I is of economic importance in agriculture. (3 marks)
Observation
Candidates responses to Question 2 was above average although many candidates could not describe their observations from the experiment but were writing the textbook version of the physical properties of each soil sample..
The expected answers include:
2. (a) Tabulation of observations from the experiment
(b) Crops that can be grown on specimen H (Sandy soil)
- Groundnut
- Cowpea
- Soyabean
- Millet
- Coconut
- Oil palm
- Cotton
- Sugar cane
- Guinea corn
- Pigeon pea
(c) (i) Preferred specimen for maize production
- Specimen G (Loamy soil)
(ii) Reasons why specimen G (Loamy soil is preferred for maize production)
- It has good aeration
- Has a crumby structure
- Contains high organic matter
- Has good water retention capacity
- Leaching of nutrients is minimized
- Encourages microbial activities
- Easy to cultivate
- It is well drained
(d) Economic importance of specimen I (Earthworm) in agriculture
- Improves soil aeration
- Adds organic matter to soils/improves soil fertility
- Improves microbial activities in the soil
- Improves soil structure and granulation
- Aids in the decomposition of organic matter in the soil
- Increases the rate of water percolation in soils
- Aids plant root penetration by burrowing
- Improves the cation exchange capacity of soils
- Increases the level of nutrients in the soil
- Used as bait for catching fish
- Pulverizes the soil by mixing top soil with the subsoil
- Stabilizes soil pH through the addition of organic matter