WAEC SSCE - Agricultural Science - 1999 (Essay)

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(a) Six aims of crop improvement

1. To increase crop yield.
2. To improve resistance to pests and diseases.
3. To improve the quality and nutritional value of produce.
4. To produce early-maturing varieties.
5. To develop varieties adapted to particular environments (drought or flood tolerance).
6. To produce varieties suited to mechanization and resistant to lodging/shattering.

(b) Introduction as a method of crop improvement

Introduction is the method of crop improvement in which crop varieties or their germplasm are brought in from a region or country where they already exist to a new area where they were not previously grown. The introduced material is tested for adaptation to the new environment, and if it performs well it may be released for direct cultivation or used as parent material in further breeding work.

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(a) Extension in agriculture

Agricultural extension is an informal educational service through which useful research findings and improved farming practices are disseminated to farmers, in order to help them raise their productivity and improve their standard of living.

(b) Eight functions of an extension agent

1. Teaches farmers improved farming methods.
2. Introduces improved seeds, breeds and inputs to farmers.
3. Conducts demonstrations of new practices.
4. Organizes farmers into cooperatives and groups.
5. Conveys farmers' problems to research institutes.
6. Disseminates research findings to farmers.
7. Advises farmers on marketing and sources of credit.
8. Assists farmers in solving their farm problems and adopting innovations.

(c) Six problems of agricultural extension

1. Inadequate funding.
2. Inadequate and poorly trained extension agents.
3. Poor transportation and communication facilities.
4. A high farmer-to-agent ratio.
5. Illiteracy of farmers and their resistance to change.
6. Poor linkage between research and extension (and language barriers).

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(a) Six ways soil organisms aid the formation of soils

1. Their burrowing and movement break up rock fragments and loosen the soil.
2. They decompose plant and animal remains into humus.
3. Their movement mixes and turns over the soil layers.
4. They secrete acids and other substances that weather the parent rock/material.
5. Their burrowing improves aeration, which promotes chemical weathering.
6. Their dead bodies and excreta (casts) add organic matter to the developing soil.

(b) Four ways soil organisms improve soils for crop growth

1. They decompose organic matter, releasing nutrients for crop use.
2. They improve soil aeration through burrowing.
3. They improve soil structure and increase water infiltration and drainage.
4. Some fix atmospheric nitrogen and increase the humus/organic-matter content of the soil.

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(a) Factors affecting distribution and production of crops and animals

• (i) Climatic factors: rainfall; temperature (also wind, sunlight, humidity).
• (ii) Biotic factors: pests and diseases; weeds (also pollinators, soil organisms).
• (iii) Edaphic factors: soil texture/structure; soil pH and fertility (also soil moisture and depth).

(b) Climatic and soil requirements for optimum production

Yam

Three climatic requirements:

• High and well-distributed rainfall of about 1000-1500 mm per year.
• Warm temperature of about 25-30°C.
• Adequate sunlight and a fairly long, warm growing season.

Two soil requirements:

• Deep, well-drained, loose loamy or sandy-loam soil.
• Fertile soil rich in organic matter and slightly acidic.

Tomatoes

Three climatic requirements:

• Moderate rainfall and warm temperature of about 20-27°C.
• Adequate bright sunshine.
• Relatively low humidity to reduce disease incidence.

Two soil requirements:

• Well-drained, fertile loamy soil rich in organic matter.
• Slightly acidic soil with a pH of about 6-7.

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Production of cowpea

(a) Land preparation

Clear the vegetation and remove stumps; plough and harrow to obtain a fine tilth on well-drained loamy soil; make ridges, heaps or a flat seedbed.

(b) Planting

Plant at the onset of the rains by sowing seeds directly, placing 2-3 seeds per hole at a depth of 2-4 cm, with a spacing of about 25-30 cm within rows and 60-75 cm between rows.

(c) Fertilizer application

Since cowpea is a leguminous crop that fixes its own nitrogen, apply mainly phosphate fertilizer (such as single super phosphate) to boost nodulation and yield; a little NPK may be applied 2-3 weeks after planting on poor soils.

(d) Weeding

Weed early to reduce competition; carry out the first weeding 2-3 weeks after planting and a second before flowering, using a hoe or a selective herbicide, taking care not to damage the shallow roots.

(e) Harvesting

Harvest when the pods are mature and dry (turned brown) by picking them by hand, preferably in dry weather and in stages as the pods ripen.

(f) Processing

Dry the pods further in the sun, thresh to release the seeds, then winnow to remove the chaff.

(g) Storage

Store the clean, dry seeds in air-tight containers or hermetic bags in a cool, dry place, treating them with an approved preservative/insecticide to guard against weevils (bruchids).

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(a) Poor transportation - four solutions

1. Construct and rehabilitate rural (feeder) roads linking farms to markets.
2. Provide adequate and affordable transport vehicles for moving produce.
3. Develop alternative means such as water and rail transport.
4. Establish agro-service centres and storage points close to farming areas, and maintain existing roads.

(b) Inadequate farm inputs - four solutions

1. Government should subsidize the cost of inputs.
2. Establish agro-service/input distribution centres in rural areas.
3. Encourage local manufacture of inputs to increase supply.
4. Ensure timely distribution and provide credit for farmers to buy inputs.

(c) Crude tools - four solutions

1. Introduce and subsidize modern machines and implements.
2. Establish tractor and equipment hiring services.
3. Train farmers in the use and maintenance of improved equipment.
4. Encourage local fabrication of improved tools and provide credit for their purchase.

(d) Inadequate storage facilities - four solutions

1. Construct modern storage structures and silos.
2. Provide cold-storage and processing facilities to reduce spoilage.
3. Educate farmers on improved on-farm storage methods and use of storage chemicals.
4. Establish community/cooperative stores and encourage processing of produce.

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(a) Six functions of protein in the body of a farm animal

1. It is used for growth and formation of new body tissues.
2. It is used for the repair of worn-out tissues.
3. It is used for the formation of enzymes.
4. It is used for the formation of hormones.
5. It is used for the formation of antibodies that fight diseases.
6. It is used for the production of animal products such as milk, meat and eggs (and can serve as a source of energy in excess).

(b) Sources of protein used in livestock feeding

(i) Five animal-protein sources:

• Fish meal
• Blood meal
• Meat meal
• Bone (meat-and-bone) meal
• Milk/skimmed milk (or maggot meal)

(ii) Five plant-protein sources:

• Groundnut cake
• Soybean meal
• Cotton seed cake
• Palm kernel cake
• Beniseed (sesame) cake or leaf meal

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(a) Four farming operations requiring electric power

1. Pumping of water for irrigation.
2. Lighting and brooding in poultry houses, and incubation of eggs.
3. Milking with milking machines.
4. Grinding/milling of grains and feed, and refrigeration/cold storage of produce.

(b) Three advantages and three disadvantages of each farm power

(i) Electricity

Advantages:

• It is clean and causes no pollution.
• It is convenient and easy to use and control.
• It is efficient and reliable where supply is steady.

Disadvantages:

• It is not available in many rural farming areas.
• It is expensive to install.
• It is dangerous (risk of electrocution) and is affected by power failure.

(ii) Animal (draught) power

Advantages:

• It is cheap to acquire and requires no fuel.
• It provides manure and, ultimately, meat and hide.
• It is suitable for small farms and rough terrain.

Disadvantages:

• It is slow and gives low power output.
• It must be fed and cared for even when not working.
• It can work only for limited hours and may be lost to disease or death.

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(a) Four breeds of goats

• West African Dwarf
• Red Sokoto (Maradi)
• Sahel (West African Long-legged)
• Kano Brown (or Boer, Saanen, Anglo-Nubian)

(b) Extensive system of rearing a ruminant

In the extensive system, the animals (for example cattle or goats) are allowed to roam and graze freely over a large area of natural pasture or rangeland. There is little or no supplementary feeding, housing and management are minimal, and the animals search for their own feed and water. It requires low capital and labour and is suited to areas with abundant land, but productivity per animal is low and control of pests, diseases and breeding is difficult.

(c) Three reasons for rearing goats

1. For the production of meat (chevon).
2. For milk.
3. For skin/hide and as a source of income (also for manure).

(d) Three common diseases of cattle

• Rinderpest
• Foot-and-mouth disease
• Anthrax (or trypanosomiasis, contagious bovine pleuropneumonia)

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(a) Farm valuation

Farm valuation is the process of estimating or determining the monetary value of a farm and its assets (land, buildings, livestock, produce and equipment) at a particular point in time.

(b) Profit and Loss Account of the farm

Total expenditure = N659,800.00; total income (sales plus closing valuation) = N650,000.00. Since expenditure exceeds income, the farm made a net loss of N9,800.00 (659,800 - 650,000), which is entered on the credit side to balance the account.