IGCSE Agriculture

Fruit production

A fruit is the mature, fertilised ovary of a plant. Botswana doesn't grow a large volume of fruit compared to crops like sorghum or maize, but fruit production still matters for both nutrition and income, and it's a regular exam topic because it touches farming practice, plant care, and food science all at once.

Fruits fall into two groups. Indigenous fruits grow naturally in Botswana — morojwa (snot-apple), mmilo (wild medlar), mowana (baobab), and moretlwa (wild raisin) are common examples. Exotic fruits were introduced from elsewhere — banana, orange, mango, apple, and guava are typical ones grown or sold locally.

Each type has real trade-offs worth knowing for exam questions that ask you to compare them:

• Indigenous fruits need no special care since they're already adapted to local conditions, and they're cheaper — but their seeds and seedlings are hard to find, and there's little written knowledge on how to grow them commercially.
• Exotic fruits have established growing knowledge and seedlings that are easy to buy — but they're expensive to grow, often need more water and care than local conditions naturally provide, and can bring pests and diseases with them.

Why fruit matters nutritionally

Fruits supply the body with carbohydrates (energy), vitamins and minerals (which strengthen the immune system), fibre (which keeps digestion working properly), some protein, and water. This is also why fruit is specifically recommended for people living with HIV/AIDS: the vitamins and minerals support a weakened immune system, the carbohydrates provide energy, and the high water content makes fruit easy to digest during illness.

Planting a fruit tree

Fruit trees are grown in an orchard. Getting the planting hole right matters more than most students expect, since it directly affects how well the roots establish:

• Dig the hole using a pick and shovel, keeping the topsoil and subsoil separated as you go.
• Dig as deep as reasonably possible — this improves aeration and lets both water and roots penetrate more easily.
• Mix the topsoil with manure and fertiliser before it goes back in.
• Remove any plastic bag carefully so the roots and surrounding soil aren't disturbed, place the tree centred in the hole, then firm the soil down around it to remove air pockets.
• Use the leftover subsoil to build a basin or ridge around the tree, then water it in.

Managing fruit trees after planting

Ten management practices show up repeatedly in past papers:

• Watering — supplements rainfall; trees should be watered enough but never over-watered, since water is what carries food and air to the plant.
• Pruning — removing diseased, infested, or dead parts to stop disease spreading and stop nutrients being wasted on unproductive growth. Pruning also triggers flowering in some fruit trees (grapes are the classic example) and lets sunlight reach more of the plant, helping fruit ripen.
• Training — shaping a tree, mostly for decorative purposes; common in grapevines.
• Fertiliser application — applied before/at planting is called basal dressing; applied while the tree is already growing is called top dressing. This distinction comes up often in exams.
• Mulching — covering the soil to reduce evaporation and regulate temperature; if the mulch is organic (grass, leaves, twigs) it eventually rots into humus and adds nutrients back to the soil.
• Pest and disease control — using pesticides, or hand-picking pests where appropriate.
• Weeding — removing weeds that compete with the tree for space, nutrients, water, air and sunlight, using weedicides or tools like a spade, hoe, or rake.
• Cultivation — loosening the soil (typically with a rake) to improve aeration and let roots and water penetrate.
• Staking — supporting trees with weak stems (again, grapes are a common example) using poles, wires, or string.
• Harvesting — picking fruit once ripe, then cleaning and grading it before it's packaged for sale.

Preserving fruit

Since fruit is highly perishable, preserving it protects it from rotting and keeps it available beyond the harvest season. Four methods matter for this level:

• Refrigeration — storing fruit at low temperatures (roughly 1–4°C) to slow the microorganisms that cause rotting.
• Freezing — storing fruit below 0°C, which makes microorganisms inactive rather than just slow.
• Dehydration — removing moisture (often by drying in the sun), since microorganisms need moisture to grow.
• Canning — sealing cleaned, sliced fruit in cans with sugar or juice added, which helps draw out water and prevent rotting.

Records and marketing

A production record is written information showing how much fruit was harvested and when — farmers need accurate records, since false or missing information leads to poor business decisions. Once harvested, fruit goes through a marketing process: cleaning, grading by size, packaging, pricing, and transporting to where it will actually be sold.

What weathering is

Weathering is the breakdown of rocks into smaller particles over time, which is where soil ultimately comes from. There are three main types, and past papers regularly ask you to identify or explain a specific one from a diagram or scenario:

• Physical weathering — rocks break apart due to physical forces, without any change in their chemical makeup. Repeated heating and cooling causes rock to expand and contract until it cracks; water freezing in cracks and expanding does the same thing.
• Chemical weathering — rock is broken down through a chemical reaction, such as rainwater (slightly acidic) dissolving certain minerals over time.
• Biological weathering — living organisms break down rock, most commonly plant roots growing into cracks and forcing them wider as the root thickens.

The soil profile

A soil profile is a vertical cross-section of soil showing its distinct layers, called horizons. From top to bottom:

• Topsoil — the uppermost, darkest layer, rich in organic matter (humus) and generally the most fertile; this is where most plant roots and nutrients are found.
• Subsoil — below the topsoil, lighter in colour, with less organic matter but often more minerals.
• Parent rock (bedrock) — the solid rock at the base of the profile, which weathers over long periods to eventually form the soil above it.

Studying the soil profile matters practically: it tells a farmer how deep the fertile layer is, how well water and roots can penetrate, and therefore what will grow well in a given field.

Soil erosion

Soil erosion is the wearing away and removal of topsoil, most often by wind or water. It's a serious problem because topsoil — the most fertile layer — is lost, and it takes a very long time to form naturally. Common prevention methods include planting cover crops or grass to hold soil in place, contour ploughing (ploughing across a slope rather than straight down it), and avoiding overgrazing, which strips away the vegetation that would otherwise protect the soil.

Hand tools

• Hoe — used for weeding, breaking up soil, and making planting furrows; one of the most common tools on small Botswana farms.
• Spade — used for digging holes, such as when planting a tree or digging a trench.
• Rake — used for levelling soil, gathering crop residue, and light cultivation to improve aeration.
• Pick — used for breaking up hard or compacted ground before digging.
• Pruning shears — used for cutting away dead, diseased, or unwanted plant growth.
• Watering can — used to apply water directly to plants, particularly seedlings and young trees.

Machinery and implements

Larger-scale farms use tractor-drawn implements to cover more ground faster:

• Plough — turns over and breaks up soil ahead of planting, burying old crop residue and bringing fresh soil to the surface.
• Harrow — used after ploughing to break up remaining soil clumps and create a finer, more even seedbed.
• Planter — sows seeds at a consistent depth and spacing, much faster and more evenly than planting by hand.
• Disc harrow — a set of rotating discs that cut through soil and plant residue, commonly used for the same job as a plough on some farms.

Choosing between tools

Exam questions sometimes ask you to name a hand tool that does the same job as a piece of machinery, or vice versa — for example, a hoe and a plough both prepare soil for planting, just at very different scales. The general trade-off is that hand tools are cheaper and need no fuel but cover ground slowly, while machinery is fast and covers large areas but requires money for fuel, maintenance, and often the machine itself.