BGCSE Agricultural Science 1517 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Soil texture

The relative proportions of sand, silt, and clay particles in a soil. It influences water retention, drainage, aeration, and nutrient-holding capacity.

Cation exchange capacity

The ability of soil particles, especially clay and organic matter, to hold exchangeable positive ions. Higher CEC means greater nutrient storage.

Field capacity

The water content remaining in soil after excess water has drained away by gravity. It represents water available to plants under normal conditions.

Permanent wilting point

The soil water content at which plants can no longer extract water and remain wilted even after adding water. Water below this point is unavailable.

Seed germination

The process in which a viable seed absorbs water, resumes metabolism, and produces a radicle and shoot under suitable moisture, oxygen, and temperature.

Crop rotation

The planned sequence of different crops on the same land over seasons. It helps control pests, improve soil fertility, and reduce erosion.

Transplanting

Moving seedlings from a nursery to the field after they have developed enough roots and leaves. It gives uniform stands and reduces early weed competition.

Rumen

The largest stomach compartment of ruminants, where microbes ferment fibrous feed. It produces volatile fatty acids and microbial protein used by the animal.

Colostrum

The first thick milk produced after birth, rich in antibodies and nutrients. Young animals receive it soon after birth to obtain passive immunity.

Feed conversion ratio

The amount of feed consumed divided by the live weight gain produced. A lower value indicates more efficient conversion of feed into animal product.

Vaccination

Introducing a weakened, killed, or subunit antigen to stimulate protective immunity without causing serious disease. It reduces susceptibility during later exposure.

Quarantine

Isolating newly arrived or sick animals from the herd to prevent spread of infectious disease. It allows observation and testing before mixing.

Zoonosis

An infectious disease that can be transmitted from animals to humans, such as rabies or brucellosis. Control requires hygiene and animal health measures.

Integrated pest management

A combined strategy using cultural, biological, physical, and chemical methods to keep pests below damaging levels, with pesticides used only when justified.

Economic threshold

The pest population density at which the cost of control equals the value of crop damage prevented. Control is justified when pest numbers exceed this level.

Biological control

Using natural enemies such as predators, parasitoids, or pathogens to reduce pest populations. It works best when broad-spectrum pesticides are avoided.

Knapsack sprayer

A portable sprayer carried on the back, used to apply pesticides or liquid fertilizer. It requires calibration and regular cleaning to give accurate, safe application.

Power take-off

A shaft on a tractor that transmits engine power to implements such as mowers, pumps, or sprayers. Guards must be kept in place for safety.

Primary tillage

The first soil cultivation operation, often done with a plough, which breaks and inverts the soil to prepare for seedbed making.

Gross margin

Gross output value minus variable costs for an enterprise. It measures returns before fixed costs and helps compare enterprise profitability.

Fixed costs

Farm expenses that do not change with the level of production in the short run, such as rent, insurance, and depreciation.

Depreciation

The annual loss in value of a farm asset due to wear, age, or obsolescence. It is recorded as a cost even when no cash is spent.

Conservation agriculture

A farming system based on minimum soil disturbance, permanent soil cover, and crop rotation. It conserves moisture, reduces erosion, and improves soil health.

Agroforestry

Growing trees together with crops or livestock on the same land. It can provide shade, wind protection, fodder, fruit, and improved soil fertility.

Ecosystem services

Benefits that people obtain from functioning ecosystems, including pollination, nutrient cycling, water purification, and soil formation. Agriculture depends on these services.

Grafting

Joining a scion from one plant to the rootstock of another so they grow as one. It is used to combine desirable fruit quality with disease-resistant roots.

Hybrid seed

Seed produced by crossing two genetically distinct inbred lines. The first generation is often uniform and high-yielding, but saved seed may not breed true.

Hardening off

Gradually exposing nursery seedlings to outdoor conditions before transplanting. It reduces transplant shock by thickening cuticles and adjusting growth.

Soil sampling

Collecting representative soil cores from a field, usually in a zig-zag pattern, mixing them, and sending a subsample for laboratory analysis.

Quadrat

A square frame of known area used to sample plants or pests. Counts within it are scaled to estimate field populations.

Germination percentage

The number of seeds that germinate divided by the total number sown, multiplied by one hundred. It helps calculate reliable seed rates.

Pre-harvest interval

The minimum time between applying a pesticide and harvesting the crop. Following it helps ensure residues do not exceed safe limits.