WAEC SSCE - Agricultural Science - 2007 (Practical)
Frage 1 Bericht
Study the diagrams below and use them to answer questions (a) to (c).
a) ldentify the equipment illustrated by diagrams D, E, F, and G.
(b) State the farm operation for which the equipment illustrated by diagrams D,E,F and G.
(c) Enumerate two specific uses of each of the equipment illustrated by diagrams F and G.
(d) State six general ways of maintaining the equipment illustrated by diagrams F and G.
(a) Identification of the equipment:
- D - Gunter's chain
- E - Cross staff
- F - Prismatic compass
- G - Theodolite
(b) Farm operation for which they are used: They are all survey equipment, used for farm surveying (measuring and mapping farmland).
(c) Two specific uses of each of F and G:
F - Prismatic compass:
- Locating a baseline or particular places on the land.
- Taking the direction (bearing) of lines with reference to the magnetic meridian.
G - Theodolite:
- Measuring horizontal and vertical angles.
- Determining the elevation of, and sighting or locating, survey stations.
(d) Six general ways of maintaining equipment F and G:
- Clean or wash and dry the equipment properly after every use.
- Grease or oil the necessary metal parts to prevent rust.
- Ensure the screws, bolts and nuts are properly tightened and secured after use.
- Protect the equipment from getting wet, particularly the theodolite (G).
- Use the equipment strictly according to the manufacturer's instructions.
- Store the equipment in a cool, dry place after cleaning, and keep the prismatic compass (F) away from magnetic fields.
Antwortdetails
(a) Identification of the equipment:
- D - Gunter's chain
- E - Cross staff
- F - Prismatic compass
- G - Theodolite
(b) Farm operation for which they are used: They are all survey equipment, used for farm surveying (measuring and mapping farmland).
(c) Two specific uses of each of F and G:
F - Prismatic compass:
- Locating a baseline or particular places on the land.
- Taking the direction (bearing) of lines with reference to the magnetic meridian.
G - Theodolite:
- Measuring horizontal and vertical angles.
- Determining the elevation of, and sighting or locating, survey stations.
(d) Six general ways of maintaining equipment F and G:
- Clean or wash and dry the equipment properly after every use.
- Grease or oil the necessary metal parts to prevent rust.
- Ensure the screws, bolts and nuts are properly tightened and secured after use.
- Protect the equipment from getting wet, particularly the theodolite (G).
- Use the equipment strictly according to the manufacturer's instructions.
- Store the equipment in a cool, dry place after cleaning, and keep the prismatic compass (F) away from magnetic fields.
Frage 2 Bericht
Study carefully the experimental set-ups labelled A, B and C.
(a) What is the aim of the experiment for which the apparatus has been set up?
(b) List the experimental set-ups in the order in which water has risen through the soil samples, starting with the highest
(c) List six items of apparatus used in the experimental set-up.
(d) Describe briefly the procedure used in setting up the experiment.
(e) Why is there a difference in the water levels of the soil samples in the set ups labelled B and C?
(a) Aim of the experiment: The apparatus is set up to compare the capillary attraction (capillarity) of different soil types, that is, to determine and compare the rate and height to which water rises through samples of clay, loam and sandy soil.
(b) Order in which water has risen, starting with the highest:
- Set-up C (sandy soil) - highest
- Set-up A (loamy soil) - middle
- Set-up B (clayey soil) - lowest
Within the time allowed for the experiment, water rises fastest and highest through the coarse sand; over a much longer period the order would change as the clay absorbs and holds more water.
(c) Six items of apparatus used:
- A large beaker, basin, dish or trough
- Three capillary (glass) tubes
- Soil samples A, B and C (clay, loam and sand)
- Water
- Cotton wool
- Clamps and retort stands
(d) Procedure:
- Take three glass tubes and plug each at the lower end with cotton wool.
- Dry the soil samples and break up the lumps into fine particles.
- Fill each tube with an equal quantity of the dry clayey, loamy and sandy soil respectively.
- Fix the three tubes upright with the clamps and retort stands.
- Dip the lower ends of the three tubes to the same depth into the trough of water.
- Allow the set-up to stand for the required time.
- Watch the upward movement of water into each soil sample and record the height of rise in each tube.
(e) Reason for the difference in water levels between B and C: In set-up C (sand), the larger particles and wider pore spaces allow water to rise quickly by capillarity, but the rise soon stops because the large pores give only weak capillary attraction. In set-up B (clay), the very fine particles and tiny pore spaces let water rise only slowly at first; but as the clay particles absorb water and swell, the capillary attraction becomes stronger, so given more time the water eventually rises higher in the clay than in the sand. The difference in water level is therefore due to the difference in particle size and pore space of the two soils.
Antwortdetails
(a) Aim of the experiment: The apparatus is set up to compare the capillary attraction (capillarity) of different soil types, that is, to determine and compare the rate and height to which water rises through samples of clay, loam and sandy soil.
(b) Order in which water has risen, starting with the highest:
- Set-up C (sandy soil) - highest
- Set-up A (loamy soil) - middle
- Set-up B (clayey soil) - lowest
Within the time allowed for the experiment, water rises fastest and highest through the coarse sand; over a much longer period the order would change as the clay absorbs and holds more water.
(c) Six items of apparatus used:
- A large beaker, basin, dish or trough
- Three capillary (glass) tubes
- Soil samples A, B and C (clay, loam and sand)
- Water
- Cotton wool
- Clamps and retort stands
(d) Procedure:
- Take three glass tubes and plug each at the lower end with cotton wool.
- Dry the soil samples and break up the lumps into fine particles.
- Fill each tube with an equal quantity of the dry clayey, loamy and sandy soil respectively.
- Fix the three tubes upright with the clamps and retort stands.
- Dip the lower ends of the three tubes to the same depth into the trough of water.
- Allow the set-up to stand for the required time.
- Watch the upward movement of water into each soil sample and record the height of rise in each tube.
(e) Reason for the difference in water levels between B and C: In set-up C (sand), the larger particles and wider pore spaces allow water to rise quickly by capillarity, but the rise soon stops because the large pores give only weak capillary attraction. In set-up B (clay), the very fine particles and tiny pore spaces let water rise only slowly at first; but as the clay particles absorb water and swell, the capillary attraction becomes stronger, so given more time the water eventually rises higher in the clay than in the sand. The difference in water level is therefore due to the difference in particle size and pore space of the two soils.
Frage 3 Bericht
Observe specimens H, l, J, and K carefully.
(a) State one method of propagation of each of the specimens
(b) State four advantages of staking the crop which specimen I is obtained.
(c) Name the toxic substance present in specimen H and give two methods of reducing it
(d) Describe the processing of specimen H into garri.
(a) One method of propagation of each specimen
- Specimen H (cassava): stem cutting.
- Specimen I (yam): seed yam (whole small tubers or yam setts).
- Specimen J (sweet potato): vine or stem cuttings.
- Specimen K (ginger): rhizome (setts).
(b) Four advantages of staking the crop from which specimen I (yam) is obtained
- The stakes support the climbing vines and hold them off the ground.
- They expose the leaves for good interception of sunlight and better photosynthesis.
- They minimise damage to the vines and prevent the transmission of soil-borne pathogens to the leaves through rain splash.
- They allow good air circulation and give the farmer more room to carry out cultural practices, leading to higher yields.
(c) Toxic substance in specimen H (cassava) and two methods of reducing it
The toxic substance is hydrocyanic acid (prussic acid, from a cyanogenic glycoside). It can be reduced by:
- Fermentation (grating and pressing out the juice).
- Boiling, sun-drying, frying or roasting.
(d) Processing of specimen H (cassava) into garri
Harvest the raw cassava tubers, peel them with a knife and wash the peeled tubers. Grate the peeled tubers with a grater, put the grated mash into sacks and screw-press (or ferment) it for about three days to drain off the juice. Sift the fermented mash to remove fibres and lumps, then fry it in a pan over fire with constant stirring until dry and crisp. Sift the fried garri again into fine or coarse grades and bag it for storage or sale.
Antwortdetails
(a) One method of propagation of each specimen
- Specimen H (cassava): stem cutting.
- Specimen I (yam): seed yam (whole small tubers or yam setts).
- Specimen J (sweet potato): vine or stem cuttings.
- Specimen K (ginger): rhizome (setts).
(b) Four advantages of staking the crop from which specimen I (yam) is obtained
- The stakes support the climbing vines and hold them off the ground.
- They expose the leaves for good interception of sunlight and better photosynthesis.
- They minimise damage to the vines and prevent the transmission of soil-borne pathogens to the leaves through rain splash.
- They allow good air circulation and give the farmer more room to carry out cultural practices, leading to higher yields.
(c) Toxic substance in specimen H (cassava) and two methods of reducing it
The toxic substance is hydrocyanic acid (prussic acid, from a cyanogenic glycoside). It can be reduced by:
- Fermentation (grating and pressing out the juice).
- Boiling, sun-drying, frying or roasting.
(d) Processing of specimen H (cassava) into garri
Harvest the raw cassava tubers, peel them with a knife and wash the peeled tubers. Grate the peeled tubers with a grater, put the grated mash into sacks and screw-press (or ferment) it for about three days to drain off the juice. Sift the fermented mash to remove fibres and lumps, then fry it in a pan over fire with constant stirring until dry and crisp. Sift the fried garri again into fine or coarse grades and bag it for storage or sale.
Frage 4 Bericht
(a) State a breed of specimen L which may be used for only commercial egg production.
(b) How long does it take an improved specimen L from day old to reach its point of lay
(c) Name any four features on the head of specimen Lour diseases that attack specimen L.
(d) Mention three parasites and four diseases that attack specimen L
(e) Mention two ways of controlling the parasites mentioned in (d) above
Specimen L is the domestic fowl (laying hen).
(a) A breed used for only commercial egg production
The White Leghorn (other light egg-type layers such as Black Leghorn, Ancona and Minorca are also acceptable).
(b) Time from day-old to point of lay for an improved layer
About 18 to 20 weeks (approximately five months).
(c) Four features on the head of specimen L
- Comb
- Wattles
- Beak
- Eyes (the ear lobe and nostrils are also on the head)
(d) Three parasites and four diseases that attack specimen L
Three parasites:
- Lice
- Mites
- Roundworms (fleas and ticks also attack the fowl)
Four diseases:
- Newcastle disease
- Fowl pox
- Coccidiosis
- Fowl typhoid (fowl cholera, Gumboro and pullorum are also acceptable)
(e) Two ways of controlling the parasites mentioned in (d)
- Dust or spray the birds and the poultry house with the recommended insecticide/acaricide powder, and deworm the birds regularly with anthelmintics.
- Maintain good sanitation and hygiene by regular cleaning and disinfection of the house, changing the litter, isolating infected birds and avoiding overcrowding.
Antwortdetails
Specimen L is the domestic fowl (laying hen).
(a) A breed used for only commercial egg production
The White Leghorn (other light egg-type layers such as Black Leghorn, Ancona and Minorca are also acceptable).
(b) Time from day-old to point of lay for an improved layer
About 18 to 20 weeks (approximately five months).
(c) Four features on the head of specimen L
- Comb
- Wattles
- Beak
- Eyes (the ear lobe and nostrils are also on the head)
(d) Three parasites and four diseases that attack specimen L
Three parasites:
- Lice
- Mites
- Roundworms (fleas and ticks also attack the fowl)
Four diseases:
- Newcastle disease
- Fowl pox
- Coccidiosis
- Fowl typhoid (fowl cholera, Gumboro and pullorum are also acceptable)
(e) Two ways of controlling the parasites mentioned in (d)
- Dust or spray the birds and the poultry house with the recommended insecticide/acaricide powder, and deworm the birds regularly with anthelmintics.
- Maintain good sanitation and hygiene by regular cleaning and disinfection of the house, changing the litter, isolating infected birds and avoiding overcrowding.
