WAEC SSCE - Agricultural Science - 2015 (Practical)

Maelezo ya Majibu

(a) Two uses each of specimens P, Q and R

P (Electric bulb):

• Provides light/illumination in poultry and animal houses.
• Provides warmth for brooding chicks and in incubators.

Q (Garden fork):

• Loosening, turning and aerating the soil.
• Lifting and harvesting root/tuber crops and turning compost/manure.

R (Hand trowel):

• Transplanting and lifting seedlings.
• Digging small holes for planting and mixing/applying soil or manure in the nursery.

(b) Three problems from a poorly maintained specimen S (Knapsack sprayer)

1. Blockage of the nozzle, giving uneven or incomplete spraying.
2. Leakage of chemicals onto the operator, causing a health hazard.
3. Loss of pressure leading to poor atomization and ineffective/inaccurate application.

(c) Three protective devices to be worn when using specimen S

• Nose mask/respirator.
• Hand gloves.
• Overall (protective clothing) and rubber boots or goggles.

(d) Three precautions when using specimen S

1. Spray along the direction of the wind, never against it.
2. Do not eat, drink or smoke while spraying, and wash the body and equipment thoroughly after use.
3. Check for and repair leakages, and never clear a blocked nozzle by blowing with the mouth.

Maelezo ya Majibu

(a) Four ways specimen V (Earthworm) is important in agriculture

1. Its burrowing improves soil aeration and drainage.
2. Its casts add nutrients and improve soil fertility.
3. It aids the decomposition of organic matter, promoting humus formation.
4. It improves soil structure and can serve as feed for fish and poultry (also an indicator of soil fertility).

(b) Steps in processing specimens W and X

W (Paddy rice) into polished rice:

1. Threshing the harvested paddy to detach the grains.
2. Drying the paddy to a safe moisture content.
3. Hulling/dehusking to remove the husk, giving brown rice.
4. Milling/polishing to remove the bran layer.
5. Winnowing and cleaning, then grading and bagging the polished rice.

X (Groundnut seeds) into groundnut cake:

1. Drying the pods and decorticating (shelling) to obtain the seeds.
2. Cleaning and then roasting the seeds.
3. Grinding/crushing the roasted seeds into a paste.
4. Expelling (pressing out) the oil from the paste.
5. The residue left after oil extraction is pressed and dried to form groundnut cake.

(c) Three measures for controlling specimen Y (Maize stem borer)

• Practise crop rotation and early planting.
• Destroy and burn crop residues (stalks) after harvest to kill hibernating larvae.
• Use resistant varieties and apply appropriate insecticides.

Maelezo ya Majibu

(a)(i) Major feed nutrient in specimens A and E

• A (Bone): Mineral matter, mainly calcium and phosphorus.
• E (Cowpea): Protein.

(a)(ii) Three economic uses each of specimens A, B and C

A (Bone):

1. Ground into bone meal as a mineral supplement in livestock feed.
2. Used as bone-meal fertilizer to supply phosphorus to crops.
3. Used in the manufacture of glue, gelatine, buttons and ornaments.

B (Horn):

1. Used for making combs, buttons and ornaments.
2. Used for making handles of tools and drinking/blowing containers.
3. Processed into glue and hoof-and-horn meal (fertilizer/feed).

C (Hoof):

1. Used in the manufacture of glue and gelatine.
2. Ground into hoof meal used as fertilizer or feed supplement.
3. Used for making buttons and ornamental articles.

(b)(i) Two functions of specimen D (Water) in farm animals

• Regulates body temperature.
• Serves as a medium for transport of digested nutrients and excretory waste in the body (also aids digestion).

(b)(ii) Two benefits of including specimen E (Cowpea) in a crop rotation programme

• Being a legume, its root nodules fix atmospheric nitrogen, thereby improving and replenishing soil fertility.
• It breaks the life cycle of pests and diseases of the preceding crop, and its residues add organic matter to the soil.

Maelezo ya Majibu

(a) Botanical names of the specimens

(b) One reason why each of I, J and K is difficult to control

• I (Spear grass): It reproduces by tough, deep, creeping underground rhizomes that resprout even after the shoots are cut.
• J (Elephant grass): It is a vigorous perennial that propagates readily from rhizomes and stem cuttings and also produces many seeds.
• K (Pig weed): It produces a very large number of long-viable seeds and grows and matures very rapidly.

(c) Two uses of specimen J (Elephant grass)

• Used as fodder/forage and for making silage for livestock.
• Used for mulching and for checking soil erosion (also for fencing/boundary marking).

(d) Five ways the weeds are of economic importance to farmers

1. They compete with crops for nutrients, water, light and space, thereby reducing crop yield.
2. They harbour crop pests and diseases, serving as alternative hosts.
3. They increase the cost of production through extra spending on weeding labour and herbicides.
4. They contaminate harvested produce, lowering its quality and market value.
5. Some (e.g. elephant grass and pig weed) are useful as fodder, mulch or vegetables/medicine, giving farmers additional benefits.