NYSTCE Agriculture CST flashcards

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

Monocot versus dicot

Monocots have one cotyledon, parallel leaf veins, scattered vascular bundles, and fibrous roots; dicots have two cotyledons, netted veins, ringed bundles, and a taproot.

Soil texture triangle

A chart that classifies soil by percentages of sand, silt, and clay, which sum to 100; loam sits near the center with balanced sand and silt and moderate clay.

Cation exchange capacity

The soil's capacity to hold positively charged nutrients such as calcium, magnesium, and potassium; it increases with clay content and organic matter and reduces leaching.

Liebig's law of the minimum

Crop yield is limited by the single scarcest nutrient or growth factor, not by the total supply of all factors.

Rhizobium nitrogen fixation

Bacteria living in root nodules of legumes convert atmospheric nitrogen gas into ammonia the plant can use, reducing the need for nitrogen fertilizer.

Economic threshold

The pest population density at which the value of crop loss prevented equals the cost of treatment, so control is justified at or above it.

Ruminant versus monogastric

Ruminants such as cattle and sheep ferment cellulose with rumen microbes; monogastric animals such as swine and poultry digest feed enzymatically and need higher-quality protein.

Integrated pest management

A decision framework using scouting, thresholds, cultural and biological controls first, and targeted pesticides only when justified, with rotation to limit resistance.

Monohybrid F2 ratio

Crossing two heterozygotes for one gene gives a 3:1 phenotypic ratio and a 1:2:1 genotypic ratio in the offspring generation.

Dihybrid F2 ratio

For two independently assorting genes, a cross of double heterozygotes yields a 9:3:3:1 phenotypic ratio in the offspring generation.

Heritability

The proportion of observed phenotypic variation in a population that is due to genetic differences; higher values mean selection produces faster genetic change.

Expected progeny difference

A predicted measure of an animal's genetic merit as a parent for a specific trait, allowing fair comparison of animals across different herds.

Heterosis

Hybrid vigor, the superior performance of crossbred offspring over the average of their parents, most useful for lowly heritable traits such as fertility.

Backcross breeding

Repeated crossing of a hybrid back to a recurrent parent to recover that parent's type while transferring one desired trait from a donor parent.

Annual genetic gain

Genetic gain per year equals selection intensity times accuracy times genetic variation, divided by generation interval; shorter intervals raise annual gain.

Break-even yield

The yield needed to cover total production costs at a given price, calculated as total costs divided by price per unit.

Marginal revenue equals marginal cost

Profit is maximized where the revenue from one more unit equals the cost of producing it; expand output while marginal revenue exceeds marginal cost.

Inelastic demand

A price elasticity of demand below one, typical of staple foods, so a large supply increase lowers total farm revenue.

Basis

The difference between a local cash price and a futures price for the same commodity, reflecting location and delivery-time factors.

Fixed versus variable costs

Fixed costs do not change with output in the short run, such as land and equipment; variable costs change with production level, such as seed and fertilizer.

Sprayer calibration formula

Output in gallons per acre equals nozzle flow rate times 5940, divided by the product of ground speed in miles per hour and nozzle spacing in inches.

Power take-off

A splined shaft on a tractor that transmits engine power to implements such as mowers and balers, standardized at 540 or 1000 revolutions per minute.

Precision agriculture

Use of GPS guidance, yield monitors, and variable-rate application to match inputs to within-field variability, improving efficiency and reducing waste.

Safe grain storage moisture

Drying grain to roughly 13 to 14 percent moisture before storage, with aeration to control temperature, prevents mold growth and insect buildup.

Rollover protective structure

A frame or cab on a tractor that protects the operator in a rollover; it is effective only when the operator wears the seatbelt.

Conservation tillage

A tillage system leaving at least 30 percent of the soil surface covered with crop residue, reducing erosion while often requiring more herbicide or drainage.

Cover crop

A crop grown mainly to protect and improve soil between cash crops, reducing erosion, adding organic matter, and cycling nutrients.

The 4Rs of nutrient management

Applying the right nutrient source at the right rate, at the right time, and in the right place to maximize uptake and minimize loss.

Riparian buffer strip

Vegetated land along a waterway that intercepts sediment, nitrogen, and phosphorus in runoff before it reaches surface water.

Pesticide resistance management

Rotating pesticide modes of action and integrating nonchemical controls slow the selection of pest populations that survive labeled rates.

Organic certification transition

Land must be managed under organic rules for a transition period, typically three years, before crops can be sold as certified organic.

Drip irrigation efficiency

Drip delivers water directly to the root zone with the least evaporation and runoff, generally more efficient than sprinkler and furrow systems.

Crop rotation benefits

Alternating crop species interrupts pest and disease cycles, improves soil structure and fertility, and reduces reliance on single-crop inputs.