BSEH SS Agriculture key terms

A decision framework that combines scouting, economic thresholds, cultural and biological controls, and judicious pesticides, using chemicals only when pest numbers justify the cost and risk of spraying.

The pest population density at which the value of crop loss prevented by control equals the cost of that control, marking the point where intervention becomes economically justified.

Suppression of pest populations using living natural enemies such as predators, parasitoids, and pathogens, applied through conservation, augmentation, or classical introduction of beneficial organisms.

An insect that develops on or inside a single host insect, killing it, and is widely used as a biocontrol agent against caterpillar and aphid pests.

The inherited ability of a pest population to survive a pesticide dose that would normally kill it, developing through repeated selection pressure and best managed by rotating modes of action.

Traces of a pesticide or its breakdown products remaining in or on produce, soil, or water after application, governed by pre-harvest intervals and maximum residue limits.

The minimum number of days that must pass between the last pesticide application and harvest of the crop, ensuring residues fall below permitted limits at consumption.

A set of four tests proving a microorganism causes a disease: it must be found in sick hosts, isolated in pure culture, reinoculated to reproduce symptoms, and re-isolated from the new host.

The concept that disease occurs only when a susceptible host, a virulent pathogen, and favorable environmental conditions coincide, so control targets any one of these three components.

The inherited ability of a crop variety to limit pest or pathogen damage, ranging from immunity to tolerance, and a cornerstone of low-input disease management.

The relative proportions of sand, silt, and clay particles in a soil, which determines water-holding capacity, drainage, aeration, and workability of the field.

The arrangement of soil particles into aggregates or peds, controlling pore space, root penetration, infiltration, and resistance to erosion and compaction.

The total negative charge on soil particles that holds exchangeable cations such as calcium, magnesium, and potassium, indicating the soil's capacity to retain plant nutrients.

The percentage of the cation exchange capacity occupied by basic cations (calcium, magnesium, potassium, sodium) rather than acidic ions, used to judge lime needs.

A measure of soil acidity or alkalinity on a 0 to 14 scale, controlling nutrient availability, microbial activity, and the choice of crops and amendments.

Detachment and transport of topsoil by water or wind, reducing fertility and rooting depth and best controlled by cover, contour farming, terracing, and windbreaks.

Plowing and planting across a slope along the contour lines, forming ridges that slow runoff and trap soil and water, a standard mechanical measure of soil conservation.

Growing different crops in a planned sequence on the same land to break pest cycles, manage nutrients, improve soil structure, and reduce dependence on external inputs.

The number of crops harvested from a unit of land in one year, expressed as a percentage of the standard single-crop area, and raised by multiple cropping.

Growing two or more crops simultaneously in the same field in a defined arrangement, using complementary canopy and root traits to raise total yield and reduce risk.

The recommended set of agronomic steps for a crop, covering variety choice, seed rate, spacing, fertilizer, water, weed and pest control, and harvest timing.

The quantity of seed sown per unit area, set by the crop, variety, seed germination percentage, and planting geometry to achieve the target plant population.

The growth stage at which water shortage causes the greatest yield loss, such as flowering or grain filling, so irrigation must be assured at that point.

The amount of crop biomass or marketable yield produced per unit of water used, raised by efficient irrigation methods, mulching, and moisture-conserving tillage.

Applying water slowly and directly to the root zone through emitters in tubes, saving water and fertilizer while reducing foliar disease, but requiring filtration and maintenance.

Delivering soluble fertilizers through an irrigation system, usually drip, so nutrients reach the root zone in small frequent doses matched to crop demand.

Removing off-type, diseased, or volunteer plants from a crop or seed field to maintain varietal purity and limit disease spread before seed production.

The proportion of seeds in a sample that produce normal seedlings under standard test conditions, used to set seed rate and judge seed quality.

A factor that adjusts reference evapotranspiration to estimate water use by a specific crop at a given growth stage, used in irrigation scheduling.

Conversion of atmospheric nitrogen into plant-available ammonia by symbiotic bacteria in legume root nodules or by free-living soil microbes, reducing fertilizer nitrogen need.

A crop grown specifically to be plowed into the soil while green to add organic matter and nutrients, often a legume that also fixes nitrogen.

A seedling disease caused by soil-borne fungi that rots stems at the soil line, killing young plants, and controlled by clean media, drainage, and fungicidal drenches.

Implements and power units such as tractors, seed drills, and harvesters used to perform field operations, chosen for power match, capacity, and field efficiency.

The work rate of a machine in the field, usually hectares per hour, calculated from implement width and forward speed and reduced by turning and downtime.

The reduction in quantity or quality of produce between harvest and consumption, caused by poor handling, drying, storage pests, and lack of cold chain.

Processing or branding a raw farm product into a higher-value form, such as milling, grading, packaging, or drying, raising income and shelf life.

The difference between the price paid by the final consumer and the price received by the farmer, covering transport, handling, processing, and trader profit.

Farmers pooling produce to sell collectively, improving bargaining power, reducing per-unit transport and storage costs, and gaining access to larger buyers.

Non-formal education that helps farmers adopt improved practices through demonstrations, field days, and advisory services, using methods matched to local needs.

The stages a farmer passes through before fully using an innovation: awareness, interest, evaluation, trial, and adoption, each needing different extension support.

The proportion of total phenotypic variation in a trait that is due to genetic differences, guiding whether selection in a breeding program will be effective.

The superior performance of a crossbred progeny over its parents for traits such as yield and vigor, exploited commercially in hybrid seed production.

Choosing superior individuals from a population to become parents of the next generation, the basic method of plant and animal improvement.