Agriculture: Farming Systems, Soil, Crops and Livestock
What this domain covers
Agriculture is the deliberate growing of crops and rearing of animals for food, fibre and other products. A candidate should be able to explain the difference between subsistence farming (produce mostly consumed by the farmer's family) and commercial farming (produce mainly sold for profit), and between arable farming (crops) and pastoral farming (animals). Know the inputs of a farm system - land, labour, capital, water, seed and stock - and the outputs - crops, milk, eggs, meat, wool and waste that can be recycled as manure.
Soil and plant needs
Understand that fertile topsoil contains mineral particles, humus (decayed organic matter), air, water and living organisms. Loam, a balanced mixture of sand, silt and clay, is generally best for crops because it holds water yet drains freely. Plants need light, water, carbon dioxide, warmth and mineral nutrients, especially nitrogen for leafy growth, phosphorus for roots, and potassium for flowering and fruiting. Crop rotation and adding compost or manure maintain fertility and reduce pest build-up; monoculture repeated on the same plot depletes nutrients.
Livestock and management
Animals require suitable housing, clean water, balanced feed, health care and space. Ruminants such as cattle and goats digest grass in a specialised stomach; pigs and poultry are monogastric. Breeding, hygiene and record-keeping improve yields.
Traps in questions
Watch for questions that confuse yield per hectare with total yield, or that assume more fertiliser always means more growth - excess fertiliser can pollute waterways. Distinguish pests (insects, rodents) from diseases (pathogens) and from weeds (competitor plants). Read whether a question asks for an advantage or a disadvantage.
Worked example
A farmer harvests 4 000 kg of maize from 2 hectares. Yield per hectare = 4 000 ÷ 2 = 2 000 kg/ha. If the same farmer plants 3 hectares at that rate, expected harvest = 2 000 × 3 = 6 000 kg. Rule of thumb: divide total harvest by area to compare farms fairly.