Botswana JCE Agriculture (Syllabus 16) key terms

A vertical section through soil from the surface down to the parent rock, showing distinct layers called horizons. Each horizon differs in colour, texture and organic matter content, and the profile helps farmers judge depth, drainage and root room.

The relative proportions of sand, silt and clay particles in a soil. Texture controls how well a soil holds water and nutrients and how easily it is worked, so it guides decisions on crops, irrigation and tillage.

The way soil particles bind together into crumbs or clods, creating pore spaces. Good structure allows air and water to move freely and roots to penetrate, while poor structure causes compaction, crusting and waterlogging.

The downward movement of dissolved nutrients and salts through the soil as water drains away. Heavy rain or over-irrigation can leach nitrogen and other soluble nutrients beyond the root zone, reducing fertility and sometimes polluting groundwater.

The wearing away and removal of the fertile topsoil by wind or water. It is accelerated by bare ground, overgrazing and poor cultivation, and it reduces soil depth, fertility and crop yields over time.

Ploughing and planting along lines of equal elevation across a slope rather than up and down it. The ridges slow runoff, trap water and soil, and greatly reduce water erosion on sloping farmland.

Covering the soil surface with a layer of crop residues, grass, leaves or plastic. Mulch conserves moisture, suppresses weeds, moderates soil temperature and protects the surface from raindrop impact and erosion.

A measure of how acidic or alkaline a soil is, on a scale from about 0 to 14. Most crops grow best near neutral pH, because extreme acidity or alkalinity locks up nutrients and limits beneficial soil organisms.

A material such as ground limestone or dolomite applied to raise soil pH and neutralise acidity. Liming improves nutrient availability and crop growth, but the correct amount must be determined by soil testing.

Collecting small portions of soil from several points in a field and mixing them into one representative sample for laboratory analysis. Correct sampling depth and pattern ensure fertiliser and lime recommendations are reliable.

A material added to soil or crops to supply essential plant nutrients such as nitrogen, phosphorus and potassium. Fertilisers may be organic, like manure and compost, or inorganic, like compound fertiliser granules.

Decomposed organic matter produced by stacking plant residues and animal wastes and allowing microorganisms to break them down. Compost improves soil structure, water retention and nutrient supply and is a cheap, locally made soil amendment.

Animal dung and bedding, often mixed with urine, used to supply nutrients and organic matter to the soil. It should be well rotted before use to avoid burning young plants and to reduce weed seeds and pathogens.

The squeezing together of soil particles so that pore spaces are reduced. It occurs through trampling by livestock, repeated passes of heavy machinery and working wet soil, and it restricts root growth, drainage and aeration.

Growing different crops in a planned sequence on the same land over successive seasons. Rotation helps break pest and disease cycles, balances nutrient use, improves soil structure and reduces reliance on chemicals.

Growing two or more different crops together in the same field at the same time. It spreads risk, uses land and light more fully and can reduce pest damage, though it complicates mechanisation and harvesting.

Growing a single crop species on the same land season after season. It simplifies management and marketing but encourages build-up of pests and diseases, depletes specific nutrients and risks total loss from one problem.

Leaving land without a crop for one or more seasons so it can recover. Fallowing restores organic matter and moisture and interrupts pest cycles, but it produces no income during that period.

The prepared layer of soil in which seeds are sown. A good seedbed is fine, level, firm and free of weeds, so that seed makes close contact with moist soil and germinates evenly.

The process by which a seed absorbs water, resumes growth and produces a young shoot and root. It requires adequate moisture, suitable temperature and, for most seeds, oxygen; poor germination usually points to seed or seedbed problems.

The quantity of seed sown per unit area of land. The correct rate depends on crop, seed viability, row spacing and expected conditions, and it influences plant population, competition and final yield.

Removing excess young plants from a row so that the remaining ones have enough space, light, water and nutrients. Thinning reduces competition and helps produce stronger, more uniform plants and marketable yields.

Removing unwanted plants that compete with the crop for water, light, nutrients and space. Weeding may be done by hand, hoe, cultivator or herbicide, and timely weeding protects yield, especially in early growth stages.

A chemical used to kill or suppress weeds. Herbicides must be selected and applied carefully, at the correct dose and growth stage, to avoid crop damage, spray drift and harm to people and the environment.

Any chemical or biological product used to control pests such as insects, fungi, weeds or rodents. Safe use requires correct identification of the pest, protective clothing, correct dosage and strict observance of pre-harvest intervals.

A combined approach to pest control that uses resistant varieties, good husbandry, biological control and careful, limited pesticide use. The aim is to keep pest populations below damaging levels while reducing cost and environmental harm.

The management, feeding, breeding and general care of farm animals to keep them healthy and productive. Good husbandry covers housing, nutrition, water, health care and humane handling.

The amount of feed given to an animal over a stated period, balanced to meet its needs for energy, protein, minerals and vitamins. Rations differ for growth, maintenance, pregnancy and milk production.

Leaves, shoots and twigs of shrubs and trees eaten by livestock, especially goats and cattle in dry areas. Browse provides valuable dry-season protein and moisture but must be managed to prevent overgrazing of shrubs.

The maximum number of animals a piece of land can support sustainably without degrading the vegetation or soil. Overstocking beyond carrying capacity leads to overgrazing, erosion and poor animal condition.

Grazing land so heavily that the vegetation cannot recover. It causes loss of palatable grasses, invasion by thorny bushes, bare ground, soil erosion and lower livestock productivity in later seasons.

A primary tillage implement that cuts and turns the soil to a depth, burying weeds and residues. It may be drawn by draft animals or a tractor, and it is followed by harrows to prepare a fine seedbed.

A secondary tillage implement with discs, tines or spikes that breaks clods, levels the surface and removes small weeds. Harrowing follows ploughing to produce a finer seedbed before planting.

The mechanical working of soil for crop production, including ploughing, harrowing and weeding. Cultivation loosens soil, controls weeds and prepares seedbeds, but excessive or badly timed cultivation damages soil structure.

A self-propelled machine that supplies power to pull or drive farm implements through a drawbar or power take-off. It is used for tillage, planting, transport and operating equipment such as pumps and threshers.

A barrier of posts and wire, mesh or other material used to enclose land and control the movement of livestock and people. Good fencing enables planned grazing, protects crops and reduces stock theft.

Written or electronic accounts of farm activities, including inputs used, outputs sold, costs, animal health events and labour. Accurate records support planning, budgeting, credit applications and evaluation of enterprise performance.

The difference between the income from an enterprise and its variable costs, such as seed, fertiliser and casual labour. It helps a farmer compare enterprises and decide which to expand or drop.

The process of moving farm produce from the farm to buyers, including grading, packaging, transport, pricing and selling. Good marketing decisions strongly affect the profit a farmer finally receives.

A business owned and democratically controlled by its members, who share benefits such as bulk input purchase and collective marketing. Cooperatives help smallholders obtain inputs, credit and better prices.

A trained worker who advises farmers on improved practices and links them with research, markets and support services. The officer shares information through visits, demonstrations, field days and group meetings.