NYSTCE Agriculture CST cheat sheet

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

Soil texture triangle: sand, silt, clay percentages sum to 100; loam is roughly balanced sand/silt with moderate clay, giving good water-holding and drainage.

Cation exchange capacity (CEC) rises with clay content and organic matter; higher CEC holds more K+, Ca2+, Mg2+ against leaching.

Soil pH near 6.0-7.0 maximizes availability of most macronutrients; phosphorus is most available at pH 6.5-7.0, and micronutrients (Fe, Mn, Zn) become more available as pH falls.

Liebig's law of the minimum: yield is limited by the single scarcest nutrient, not by total nutrient supply.

Macronutrients N, P, K, Ca, Mg, S; micronutrients Fe, Mn, Zn, Cu, B, Mo, Cl, Ni. Nitrogen fixation by Rhizobium occurs in legume root nodules.

IPM hierarchy: cultural and sanitation first, then biological control, then targeted chemical control; economic threshold is pest density at which treatment cost equals crop loss.

Animal digestion: ruminants (cattle, sheep, goats) ferment cellulose in the rumen with microbes; monogastrics (swine, poultry) rely on enzymatic digestion and need higher-quality protein.

Plant breeding selection methods: mass selection, pure-line selection, hybridization, and backcrossing to transfer a single trait into an adapted variety.

Mendelian ratios: monohybrid F2 phenotype 3:1, genotype 1:2:1; dihybrid F2 phenotype 9:3:3:1 with independent assortment.

Genotype x environment interaction means a variety's ranking can change across locations or years; replicated trials across environments are needed to recommend cultivars.

Animal breeding: heritability (h2) estimates the proportion of phenotypic variation that is genetic; higher h2 gives faster response to selection.

Expected progeny difference (EPD) predicts the genetic merit of an animal as a parent for a specific trait and allows comparison across herds.

Crossbreeding exploits heterosis (hybrid vigor), most valuable for lowly heritable traits such as fertility and survivability.

Poultry and swine use hybrid lines and artificial insemination; dairy relies heavily on AI and sire summaries to increase genetic gain per year.

Genetic gain per year = (selection intensity x accuracy x genetic variation) / generation interval; shortening the generation interval raises annual gain.

Agricultural economics: profit = total revenue - total cost; fixed costs do not vary with output in the short run, variable costs do.

Break-even yield = total costs / price per unit; break-even price = total costs / expected yield.

Marginal analysis: expand production while marginal revenue exceeds marginal cost; the optimum is where MR = MC.

Elasticity of demand: inelastic (<1) for staple foods, so a supply increase can lower total farm revenue.

Enterprise budgets list expected revenue, variable costs, and returns above variable costs; whole-farm budgets add fixed costs.

Risk tools: crop insurance, forward contracts, futures hedging, and diversification; basis = local cash price - futures price.

Government programs: commodity support, conservation cost-share, and subsidized crop insurance; each has eligibility and compliance rules.

Depreciation allocates the cost of durable assets over their useful life; land is typically not depreciated because it does not wear out.

Machinery: tractor ballasting balances weight for traction versus soil compaction; power take-off (PTO) horsepower is measured at a standard 540 or 1000 rpm.

Calibrate sprayers: output (gal/acre) = (nozzle flow rate x 5940) / (ground speed in mph x nozzle spacing in inches).

Seed rate = (desired plants per acre) / (germination fraction x purity fraction), adjusted for expected field survival.

Precision agriculture uses GPS guidance, variable-rate application, and yield monitors to match inputs to within-field variability.

Irrigation efficiency: drip > sprinkler > furrow; scheduling by evapotranspiration replacement avoids both deficit and leaching losses.

Grain storage: dry to about 13-14% moisture for safe storage; aeration controls temperature and prevents mold and insect buildup.

Animal facilities require ventilation and moisture management; dairy cooling uses shade, fans, and sprinklers to limit heat stress losses.

Safety: rollover protection (ROPS) with seatbelt, PTO shields, and lockout of stored energy before maintenance are core machine-hazard controls.

Sustainable systems: cover crops reduce erosion and add organic matter; crop rotation interrupts pest and disease cycles and improves soil structure.

Conservation tillage leaves at least 30% residue cover, reducing erosion; no-till increases infiltration but may need more herbicide or drainage.

Nutrient management: the 4Rs are right source, right rate, right time, right place; nitrogen losses occur by leaching, denitrification, and volatilization.

Water quality: sediment, nitrogen, and phosphorus are the main agricultural pollutants; buffer strips and riparian zones intercept runoff.

Integrated pest management relies on scouting, thresholds, and rotating modes of action to slow pesticide resistance.

Pollinators and beneficial insects depend on habitat and reduced broad-spectrum insecticide use; label directions protect bees and groundwater.

Organic production prohibits synthetic fertilizers and most synthetic pesticides; certification requires a transition period (typically three years) before harvest.

Food systems: local and direct marketing, food hubs, and farm-to-school programs shorten supply chains; traceability and food-safety rules apply throughout.