RBSE SS Agriculture key terms

The number of crops raised on the same field in one agricultural year, expressed as a percentage of the standard single-crop area. Higher intensity means more harvests from limited land.

Growing two or more crops on the same land in a single year, either in sequence or together. It raises total output per unit area and spreads risk across seasons.

Growing two or more crops simultaneously in the same field in distinct rows or strips. Careful choice of compatible crops improves total yield and reduces pest and erosion damage.

A planned sequence of different crops on the same field over successive seasons. It interrupts pest and disease cycles, balances nutrient use, and protects soil structure.

The water transpired by a crop plus that evaporated from the soil and plant surfaces. It is the portion of irrigation water that does not return to the source.

The total negative charge on soil particles that holds exchangeable cations such as calcium, magnesium, potassium and ammonium. Higher values mean greater nutrient-holding ability and buffering.

The proportion of cation exchange sites occupied by basic cations rather than hydrogen and aluminium. It indicates general fertility and is high in neutral, well-supplied soils.

A measure of the acidity or alkalinity of the soil solution on a logarithmic scale. It governs nutrient availability, microbial activity and the choice of crops and amendments.

A crop grown mainly to be ploughed into the soil while still green, adding organic matter and nutrients. Legume species also fix atmospheric nitrogen for the following crop.

Living and dead plant and animal residues in soil at various stages of decomposition. It supplies nutrients, improves structure, holds water and feeds soil organisms.

The principle that crop growth is limited by whichever essential factor is in shortest supply, regardless of how plentiful others are. It guides balanced fertiliser and management decisions.

The soil test value below which a nutrient response to added fertiliser is likely and above which it is unlikely. It underpins fertiliser recommendation for a given crop and soil.

The proportion of total phenotypic variation in a population that is due to genetic differences. High values mean selection in that environment should produce rapid progress.

The expected improvement in a trait in the next generation from selection, calculated from heritability, selection intensity and phenotypic variability. It predicts breeding progress per cycle.

The difference between the mean of the selected parents and the mean of the whole population for a trait. It measures how strongly selection is applied.

The superior vigour, yield or other performance of a hybrid compared with its two parents. It is exploited commercially in hybrid seed production of many crops.

The reduced vigour and fertility seen when related individuals are crossed repeatedly. It results from increased homozygosity of deleterious recessive alleles.

The proportion of seeds in a sample that produce normal seedlings under specified test conditions. It is a core quality parameter used to set sowing rates.

The sum of those properties that determine the level of activity and performance of seed lots during germination and field emergence. Vigorous seed performs well even under stress.

A definite quantity of seed of one variety, produced and handled as a unit and identified by a lot number. It is the basis for sampling and quality testing.

A small plot near the home where vegetables and fruits are grown mainly for household consumption. It improves family nutrition and reduces food expenditure.

A protected or managed area where seedlings are raised before being moved to the main field. It allows better care of young plants and saves expensive seed.

Moving seedlings from a nursery bed to their final field position at a suitable age. It improves establishment, spacing and uniformity compared with direct sowing.

Gradual exposure of nursery seedlings to harsher field conditions before transplanting. It thickens tissues and reduces transplanting shock and mortality.

The pest population density at which control measures should be applied to prevent the pest from reaching the economic injury level. It avoids unnecessary spraying.

The lowest pest population density that causes crop loss equal to the cost of control. It defines the break-even point used to justify intervention.

A decision framework combining resistant varieties, biological control, cultural practices and judicious pesticides. It keeps pests below damaging levels while limiting cost and environmental harm.

The use of living natural enemies such as predators, parasitoids and pathogens to suppress pest populations. It is a cornerstone of integrated pest management.

A set of criteria used to prove that a particular microorganism causes a specific disease. It requires consistent isolation, pure culture and reproduction of symptoms.

Mating of animals of different breeds to combine desirable traits such as growth and adaptability. It usually exploits hybrid vigour in the first cross.

The period during which a female mammal secretes milk after giving birth. Its length and yield determine the economics of dairy animals.

The non-lactating interval before the next calving, usually about sixty days. It allows udder tissue to regenerate and improves the next lactation.

Gross output value minus variable costs for an enterprise. It allows comparison of enterprises and is central to farm planning decisions.

A cost that changes with the level of production, such as seed, fertiliser, casual labour and fuel. It is included in the gross margin calculation.

A cost that does not vary with the level of output in the short run, such as land rent and machinery depreciation. It is not deducted when computing gross margin.

The ratio of total discounted benefits to total discounted costs of a project or technology. A value above one indicates that the investment is worthwhile.

The decision by a farmer to use a new practice continuously on a substantial scale. It follows awareness, interest, evaluation and trial in the innovation-decision process.

An idea, practice or technology perceived as new by its potential users, whatever its actual age. Its perceived relative advantage and compatibility drive adoption.

The organised process of transferring knowledge and skills from research to farmers, and of bringing farmer problems back to research. It builds capacity rather than merely delivering messages.

A field or village method that shows a practice in operation so farmers can observe its results directly. It is an effective tool for building confidence in a new technology.

The rated power output of a tractor engine, usually stated in horsepower or kilowatts. It determines the size of implements that can be operated and the work rate.

The force required to pull an implement through the soil. It depends on soil type, implement width, depth and speed, and sets the power needed.

The rate at which an implement can cover field area per unit time, accounting for turns and stops. It is used to plan machinery and labour requirements.

The total energy available on a farm from humans, animals, engines and electricity to perform operations. Its availability and cost shape the level of mechanisation.

Deliberate integration of trees or shrubs with crops or livestock on the same land management unit. It diversifies income and improves soil and microclimate.

Growing annual crops between rows of trees or shrubs that are periodically pruned to supply mulch and nutrients. It reduces erosion and can improve soil fertility.

A row or belt of trees planted to reduce wind speed and protect crops, soil and livestock. It cuts wind erosion and evaporation and can raise yields.

The capture and long-term storage of atmospheric carbon dioxide in soil, biomass or wood products. It is a key climate-mitigation service of sustainable farming and forestry.

The proportion of water applied that is beneficially used by the crop rather than lost in conveyance, runoff or deep percolation. It measures how well irrigation water is used.

Farming that meets present food needs while conserving soil, water, biodiversity and livelihoods for future generations. It balances productivity with resource protection and profitability.

The principle that growth is controlled not by total resources but by the scarcest one, as stated by Justus von Liebig. It underlies balanced nutrient management.

A mating design in which several lines are crossed with a set of common testers to evaluate combining ability. It helps identify parents for hybrid breeding.