VCE Agricultural and Horticultural Studies cheat sheet

Systems are classified by enterprise mix: monoculture (one crop), polyculture (multiple crops), mixed farming (crops plus livestock), and intensive (high inputs per hectare) versus extensive (low inputs per hectare) production.

Gross margin = enterprise gross income minus variable costs; it excludes fixed costs, so it is used to compare enterprises within a whole-farm budget rather than to measure farm profit.

Yield is expressed per unit area (t/ha) or per animal (L/cow); total production = yield × area or × stocking rate, so gains come from either component.

Stocking rate is measured in dry sheep equivalents (DSE) per hectare; carrying capacity is the sustainable stocking rate a paddock supports in an average season.

Crop rotation rules: alternate cereal and break crops, avoid the same disease or herbicide group in consecutive seasons, and include a legume to fix nitrogen.

Phenology stages (germination, vegetative, flowering, grain fill, maturity) determine timing of inputs; frost, heat and water stress are most damaging at flowering.

Photosynthesis converts light, CO2 and water into carbohydrate; water-limited yield is set by transpiration, so irrigation scheduling targets crop water use, not soil moisture alone.

Livestock production is driven by energy intake above maintenance; feed conversion ratio = feed consumed ÷ liveweight gain, and lower values indicate greater efficiency.

Soil texture (sand, silt, clay proportions) controls water-holding capacity, drainage and nutrient retention; structure refers to how particles aggregate into peds.

Soil pH affects nutrient availability: most nutrients are most available at pH 6.0-7.0 (water), and lime raises pH while elemental sulfur or acidifying fertilisers lower it.

Cation exchange capacity (CEC) is the soil's capacity to hold exchangeable cations (cmol(+)/kg); high-clay and high-organic-matter soils generally have higher CEC.

Water erosion risk rises with slope, low ground cover and high-intensity rainfall; maintaining surface cover above about 70% greatly reduces detachment and loss.

Salinity is measured by electrical conductivity (dS/m); dryland salinity results from rising water tables bringing salt to the surface, managed by recharge control and deep-rooted perennials.

Nutrient budgets compare inputs (fertiliser, fixation, feed) with outputs (harvest, leaching, runoff); a surplus indicates accumulation or loss risk to waterways.

Riparian buffers filter sediment and nutrients and stabilise banks; buffer effectiveness increases with width and continuous vegetation.

Irrigation efficiency = water used beneficially ÷ water delivered; losses come from evaporation, deep drainage and runoff, and scheduling by soil moisture or evapotranspiration reduces them.

Disease triangle: disease occurs when a susceptible host, a virulent pathogen and a favourable environment coincide; removing any one factor prevents or reduces disease.

Integrated pest management (IPM) ranks controls as cultural, biological, physical, then chemical, and uses economic thresholds to decide when to act.

Pest monitoring uses sweep nets, pheromone traps, beat sheets and visual counts; threshold-based decisions avoid unnecessary sprays and resistance.

Herbicide resistance develops under repeated use of one mode-of-action group; rotating groups, tank mixes and non-chemical tactics slow it.

Animal welfare frameworks assess the Five Freedoms or the Five Domains (nutrition, environment, health, behaviour, mental state); welfare is a state of the animal, not a facility.

Notifiable diseases (e.g. foot-and-mouth disease, avian influenza) must be reported to authorities; biosecurity relies on quarantine, hygiene, restricted visitor access and pest control.

Vaccination produces adaptive immunity; withholding periods after treatment must be observed so residues do not enter meat, milk or eggs.

Plant quarantine and certification schemes (seed testing, pathogen-free planting material) prevent introduction and spread of pests and diseases.

Enterprise budget components: variable costs (seed, fertiliser, chemicals, casual labour), fixed/overhead costs (depreciation, insurance, rates), and gross margin as the comparison metric.

Break-even yield = total costs ÷ price per unit; break-even price = total costs ÷ expected yield; both identify the minimum performance needed to avoid loss.

Partial budget analysis compares a proposed change using added returns plus reduced costs versus added costs plus reduced returns; a positive net change favours the change.

Cash flow differs from profit: cash flow records timing of money in and out, while profit matches income and expenses to the production period.

Precision agriculture uses GPS guidance, variable-rate application, yield mapping and remote sensing to match inputs to within-paddock variability.

Sustainability has three pillars (economic, environmental, social); indicators include soil carbon, water use efficiency, biodiversity and farm business resilience.

Risk management tools include diversification, forward contracts, crop insurance, and maintaining fodder or financial reserves for drought years.

Life cycle assessment quantifies environmental impacts (e.g. greenhouse gas emissions per kg of product) from inputs through production to the farm gate.

Disease triangle: disease occurs when a susceptible host, a virulent pathogen and a favourable environment coincide; removing any one factor prevents or reduces disease.

Integrated pest management (IPM) ranks controls as cultural, biological, physical, then chemical, and uses economic thresholds to decide when to act.

Pest monitoring uses sweep nets, pheromone traps, beat sheets and visual counts; threshold-based decisions avoid unnecessary sprays and resistance.

Herbicide resistance develops under repeated use of one mode-of-action group; rotating groups, tank mixes and non-chemical tactics slow it.

Animal welfare frameworks assess the Five Freedoms or the Five Domains (nutrition, environment, health, behaviour, mental state); welfare is a state of the animal, not a facility.

Notifiable diseases (e.g. foot-and-mouth disease, avian influenza) must be reported to authorities; biosecurity relies on quarantine, hygiene, restricted visitor access and pest control.

Vaccination produces adaptive immunity; withholding periods after treatment must be observed so residues do not enter meat, milk or eggs.

Plant quarantine and certification schemes (seed testing, pathogen-free planting material) prevent introduction and spread of pests and diseases.

Enterprise budget components: variable costs (seed, fertiliser, chemicals, casual labour), fixed/overhead costs (depreciation, insurance, rates), and gross margin as the comparison metric.

Break-even yield = total costs ÷ price per unit; break-even price = total costs ÷ expected yield; both identify the minimum performance needed to avoid loss.

Partial budget analysis compares a proposed change using added returns plus reduced costs versus added costs plus reduced returns; a positive net change favours the change.

Cash flow differs from profit: cash flow records timing of money in and out, while profit matches income and expenses to the production period.

Precision agriculture uses GPS guidance, variable-rate application, yield mapping and remote sensing to match inputs to within-paddock variability.

Sustainability has three pillars (economic, environmental, social); indicators include soil carbon, water use efficiency, biodiversity and farm business resilience.

Risk management tools include diversification, forward contracts, crop insurance, and maintaining fodder or financial reserves for drought years.

Life cycle assessment quantifies environmental impacts (e.g. greenhouse gas emissions per kg of product) from inputs through production to the farm gate.