WAEC SSCE - Agricultural Science - 2001 (Essay)

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(a) Three effects of each factor on crop production

(i) Water

1. It is needed for seed germination and for the growth of the crop.
2. It is the medium of photosynthesis and dissolves and transports mineral nutrients within the plant.
3. Too little water causes wilting and death, while excess causes waterlogging, leaching and root rot.

(ii) Air

1. It supplies carbon dioxide needed for photosynthesis.
2. It supplies oxygen for respiration of roots and soil organisms.
3. It supplies nitrogen that is fixed by legumes/bacteria; strong wind, however, can cause lodging and evaporation.

(iii) Soil microbes

1. They decompose organic matter and release nutrients (humus) into the soil.
2. They fix atmospheric nitrogen and take part in nitrification, improving fertility.
3. Some are harmful, causing plant diseases and denitrification (loss of nitrogen).

(b) Edaphic and climatic factors

Three edaphic factors: soil texture, soil structure, soil pH (also soil fertility/organic matter, soil moisture).

Four climatic factors: rainfall, temperature, sunlight (light), wind (also relative humidity).

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Pasture management practices

(a) Land preparation

The land is cleared of bush, trees and stumps, then ploughed and harrowed to give a fine, firm seedbed. Where necessary the soil is limed to correct acidity, and drainage or levelling is done before planting.

(b) Three methods of propagation

1. By seeds (for grasses such as guinea grass and legumes such as stylo).
2. By cuttings/stem cuttings (e.g. elephant/Napier grass).
3. By splits or root/rhizome division (also by runners).

(c) Two methods of sowing

1. Broadcasting (scattering seeds evenly over the seedbed).
2. Drilling/row planting (placing seeds or setts in rows at a spacing).

(d) Fertilizer application

Nitrogenous fertilizers are applied to boost grass (leaf) growth, while phosphate fertilizers favour the establishment of the legume component. Fertilizer is applied at establishment and top-dressed after each grazing/cutting to maintain vigour. Farmyard manure may also be used.

(e) Grazing

The pasture should not be grazed until it is well established (usually a few months). Controlled/rotational grazing is practised at the correct stocking rate to prevent over-grazing, allow regrowth, and avoid trampling and selective feeding.

(f) Four other management practices

1. Weeding/weed control to remove undesirable plants.
2. Control of pests and diseases.
3. Irrigation/watering during the dry season.
4. Mowing/topping, and reseeding of bare patches, plus prevention of bush fire.

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(a) Processes of rock formation

(i) Igneous rocks: They are formed from the cooling and solidification of molten rock material (magma or lava). When magma cools slowly below the earth's surface it forms coarse-grained (intrusive/plutonic) rocks, and when lava cools quickly at the surface it forms fine-grained (extrusive/volcanic) rocks.

(ii) Sedimentary rocks: They are formed when rock fragments and organic remains (sediments) produced by weathering and erosion are transported, deposited in layers and then compacted and cemented together over a long time.

(iii) Metamorphic rocks: They are formed when existing igneous or sedimentary rocks are changed in form/structure by great heat and/or pressure within the earth, without melting completely.

(b) Examples

Igneous (two): granite, basalt (also gabbro).

Metamorphic (two): marble, slate (also gneiss, schist).

Sedimentary (three): limestone, sandstone, shale (also clay).

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Production of banana

(a) One common variety: Gros Michel (also Cavendish / Dwarf Cavendish).

(b) Planting materials: Suckers (sword suckers) and rhizome/corm pieces (bits); tissue-cultured plantlets may also be used.

(c) Propagation: Banana is propagated vegetatively (asexually), mainly by planting suckers or corm pieces in prepared holes at the correct spacing (about 3 m x 3 m).

(d) Husbandry: Clear and prepare the land, dig holes and plant suckers at the onset of the rains. Apply manure/fertilizer, mulch to conserve moisture, weed regularly, and irrigate in the dry season. Remove excess suckers (de-suckering), prop/support fruiting stems, and remove the male bud (de-belling); control pests and diseases.

(e) Two common pests: banana weevil (borer) and nematodes (also aphids, thrips).

(f) Two common diseases and their control:

• Panama disease (fusarium wilt): control by planting resistant varieties, crop rotation and using clean planting material.
• Sigatoka (black/yellow leaf spot): control by spraying fungicides, removing and burning infected leaves and ensuring good spacing/drainage.

(g) Maturity period: The bunch is usually ready for harvest about 9 to 12 months after planting.

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(a) Four merits of each

(i) Agriculture

1. Provides food for man and feed for livestock.
2. Supplies raw materials to industries.
3. Provides employment and income to the people.
4. Earns foreign exchange through export of produce.

(ii) Forestry

1. Supplies timber, poles, pulp and fuel wood.
2. Protects the soil against erosion and checks desertification (windbreak).
3. Serves as a habitat for wildlife and a source of medicinal plants.
4. Regulates climate/rainfall and provides recreation and foreign exchange.

(iii) Wildlife conservation

1. Preserves species from extinction and protects biodiversity.
2. Provides game meat and other animal products.
3. Promotes tourism and recreation, earning revenue.
4. Supports research, education and maintenance of ecological balance.

(b) Four non-agricultural uses of land

1. Building of houses and settlements.
2. Construction of roads, railways and airports.
3. Siting of industries and factories.
4. Mining/quarrying, and recreation grounds such as parks and stadia.

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(a) Short notes

(i) Maintenance ration: The quantity of feed given to an animal that supplies only enough nutrients to keep its body functions going and its body weight constant, with no production (no growth, milk, eggs or work).

(ii) Production ration: The extra feed given, over and above the maintenance ration, to enable an animal to carry out production such as growth, fattening, milk, eggs, wool, work or reproduction.

(iii) Balanced ration: A feed (ration) that contains all the essential nutrients (carbohydrates, proteins, fats, vitamins, minerals and water) in the correct proportions required by the animal for maintenance and production.

(iv) Malnutrition: A disorder or poor state of health that results when an animal is fed on a ration that lacks one or more essential nutrients, or has them in wrong proportions (either deficiency or excess).

(b) Four factors considered when deciding the type of feed for an animal

1. The age of the animal.
2. The physiological state/purpose (growth, pregnancy, lactation, work, egg-laying).
3. The type/species and body weight/size of the animal.
4. The health condition of the animal and the availability/cost of the feed.

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(a) Explanation of terms

(i) Appreciation: An increase in the value or worth of an item with time or age, for example land whose value rises over the years.

(ii) Depreciation: A reduction in the value or worth suffered by an article, building, machinery or equipment with age, use or wear and tear.

(iii) Salvage value: The amount for which a depreciated article is finally sold or disposed of after usage, that is the value recovered at the end of its useful life.

(b) Two farm items that normally appreciate in value

1. Land.
2. Young/growing animals (growing crops are also acceptable).

(c) Calculations

The farmer bought the tractor for N12,000.00 and later sold it for N3,000.00 after using it from 1988 to 1997 (9 years).

(i) Salvage value = the amount realised on disposal:

\[ \text{Salvage value} = N3{,}000.00 \]

(ii) Overall depreciation = cost price - salvage value:

\[ = N12{,}000.00 - N3{,}000.00 = N9{,}000.00 \]

(iii) Annual depreciation = overall depreciation ÷ number of years of use:

\[ = \frac{N9{,}000.00}{9} = N1{,}000.00 \text{ per year} \]

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(a) Explanations

(i) Agricultural finance: The branch of agricultural economics that deals with the sourcing, acquisition and management/use of money (capital) for agricultural production and other farm activities.

(ii) Agricultural credit: The loan or borrowed money (or inputs on trust) obtained by a farmer, to be repaid later usually with interest, for use in financing farm operations.

(b) Four significances of agricultural finance

1. It provides capital for the purchase of farm inputs such as seeds, fertilizer and machinery.
2. It enables expansion of the farm and adoption of improved technology, raising output.
3. It helps farmers hire labour and meet running (operating) costs.
4. It provides funds for processing, storage and marketing, and cushions the farmer against emergencies.

(c) One problem in obtaining credit from each source

1. Commercial banks: demand for collateral security which most farmers cannot provide (also high interest rates).
2. Community banks: limited/small funds available so they cannot meet large loan needs.
3. Money lenders: very high (exorbitant) interest rates.
4. Family sources: the amount available is usually small and unreliable.

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(a) Four types of individual land tenure systems

1. Inheritance: Land is passed down from parents to their children/relatives from one generation to another.
2. Purchase (freehold): An individual buys land outright and owns it permanently with a legal title.
3. Gift: Land is given freely to an individual, often as a token of appreciation or for services rendered.
4. Leasehold/renting: An individual acquires the right to use land for a stated period on payment of rent, after which it reverts to the owner. (Pledge is another form.)

(b) Land Use Act

Four advantages

1. It vests land in the government, reducing land disputes and litigation.
2. It makes land easier to acquire for public projects and development.
3. It controls land speculation and fragmentation.
4. It gives security of tenure through the Certificate of Occupancy, which can be used to obtain loans.

Four disadvantages

1. It concentrates too much power over land in the hands of the Governor/government.
2. Obtaining the Certificate of Occupancy is slow, costly and bureaucratic.
3. It can dispossess indigenous families of their ancestral land, sometimes with inadequate compensation.
4. It discourages large-scale private farming because of insecurity over long-term access to land.