Senior Agriculture – Semester Revision Flashcards

These flashcards cover key concepts from plant and animal production, soil and water management, experimental design, agricultural technology, marketing, sustainability and legislation. Use them to test knowledge and prepare for examinations.

What is the key difference in cotyledon number between monocotyledons and dicotyledons?

Monocotyledons have ONE cotyledon in the seed, dicotyledons have TWO.

In monocots, petals are found in multiples of _?

Multiples of 3.

Which venation pattern is characteristic of dicot leaves?

Net-like (reticulate) venation.

Name the two vascular tissues that make up vascular bundles.

Xylem and Phloem.

Which vascular tissue transports water and dissolved minerals upward?

Xylem.

What is the function of phloem?

It translocates products of photosynthesis (sugars) throughout the plant (two-way transport).

What root system is typical of monocots such as wheat?

A fibrous root system.

Define plant growth.

An increase in size of a plant; it occurs when photosynthetic production exceeds respiratory use, allowing new cells to form.

During which phase does a wheat plant switch from leaf production to forming an inflorescence?

At the ‘double-ridge’ stage, marking the start of the reproductive phase.

What is net assimilation rate (NAR)?

NAR = Photosynthesis rate – Respiration rate; the average increase in dry matter per unit leaf area over time.

State the photosynthesis word equation.

Carbon dioxide + Water → Glucose + Oxygen (in the presence of light and chlorophyll).

Which molecule is the immediate energy carrier produced in the light reactions of photosynthesis?

ATP (adenosine triphosphate).

Give two factors that limit photosynthesis in C3 plants.

Low light intensity and temperatures above ~25 °C.

Under high temperatures, which photosynthetic pathway (C3 or C4) is more efficient?

C4.

List two typical C4 crops.

Maize (sweetcorn) and sugarcane.

What is respiration in plants?

The continuous breakdown of glucose to release CO₂, water and energy for maintenance, growth and reproduction.

Name the plant process that moves water from roots to leaves via cohesion and adhesion.

Transpiration stream through xylem.

Which three mineral nutrients form the fertiliser acronym N-P-K?

Nitrogen, Phosphorus, Potassium.

What symbiotic bacterium fixes atmospheric nitrogen in legumes?

Rhizobium spp.

Why do legume rotations improve soil fertility?

Rhizobium in root nodules converts N₂ to ammonia, increasing soil nitrogen for subsequent crops.

Which plant hormone promotes cell elongation and apical dominance?

Auxins.

Name the hormone used commercially to ripen harvested bananas.

Ethylene.

Define a native pasture.

A pasture comprising species indigenous to Australia prior to European settlement.

State one advantage of improved (introduced) pastures over native pastures.

Higher palatability and greater feed production for livestock.

What environmental stimulus combination commonly triggers flowering in wheat?

Exposure to low temperatures (2–7 °C vernalisation) plus lengthening days (long-day response).

What is allelopathy?

Suppression or stimulation of plant growth by chemicals released from another plant.

Write the phenotypic equation P = G + E. What do the letters stand for?

P (phenotype) = G (genotype) + E (environment).

Identify two essentials of good experimental design.

Replication and randomisation (also controls and standardised conditions).

What is IPM?

Integrated Pest Management – combining cultural, biological, physical and chemical methods to keep pest populations below economic thresholds.

Why can repeated spraying with the same pesticide lead to failure?

It selects for chemical-resistant populations of the pest.

Which digestive chamber of ruminants houses most cellulose-digesting microbes?

The rumen.

Monogastric or ruminant: which class generally has a better feed-conversion ratio (FCR)?

Monogastrics (e.g. broiler chickens ~2 : 1).

Name the four compartments of the ruminant stomach in order.

Rumen, Reticulum, Omasum, Abomasum.

Give one advantage of ruminant digestion over monogastric digestion.

Ability to digest cellulose and synthesise B-vitamins and microbial protein from low-quality feeds.

Which volatile fatty acid produced in the rumen is the main glucose precursor in cattle?

Propionic acid.

Define compensatory growth.

Accelerated growth of animals after a period of feed restriction once adequate nutrition is restored.

Which hormone triggers ovulation in female mammals?

Luteinising Hormone (LH).

List two common reproductive technologies used in cattle.

Artificial insemination (AI) and embryo transfer (MOET).

State one economic benefit of using hormone growth promotants (HGPs) in beef cattle.

Increased daily weight gain and improved feed conversion efficiency.

What is the fundamental triangle illustrating disease occurrence?

Host – Pathogen – Suitable Environment (Disease Triangle).

Give two chemical signal headings found on pesticide labels in Australia.

CAUTION and POISON (others: DANGEROUS POISON, or no signal heading).

Which soil property is measured in g cm⁻³ and increases with compaction?

Bulk density.

Optimal soil pH range for most crop nutrient availability is ____?

Approximately 6.0–6.5.

Name two practices that increase soil organic matter.

Green-manure crops and reduced/minimum tillage.

What process converts ammonium to nitrate in soils?

Nitrification by Nitrosomonas and Nitrobacter bacteria.

Which component of soil organic matter is stable and improves CEC and water holding?

Humus.

What is dryland salinity mainly caused by?

Clearing deep-rooted native vegetation leading to rising saline water tables.

List two ways to mitigate irrigation salinity.

Improve water-use efficiency (e.g. drip systems) and plant deep-rooted crops/trees to lower water tables.

What is a riparian buffer and why is it important?

Vegetated strip along waterways; filters runoff, stabilises banks and improves water quality.

Define land capability class I.

Very versatile arable land suitable for intensive cultivation without special limitations.

What do the five ‘freedoms’ relate to?

Animal welfare standards ensuring basic physical and psychological well-being.

In a gross margin: Gross Margin = – Variable Costs.

Gross Income (or Total Revenue).

What is meant by vertical integration in agribusiness?

Ownership/control of multiple stages of the supply chain (production, processing, marketing).

Give one advantage of cooperative marketing for farmers.

Improved bargaining power and shared costs for storage or processing facilities.

Why is withholding period (WHP) critical when using agricultural chemicals?

Ensures residues decline to safe levels before livestock slaughter or crop harvest.

What satellite-based tool enables precision agriculture through field mapping and auto-steer?

Global Positioning System (GPS).

List two benefits of using drones in crop management.

Rapid crop scouting for pests/stress and variable-rate input application.

Explain why patents are important in ag-tech innovation.

They provide exclusive commercial rights, protecting R&D investment and encouraging innovation.

What is the role of Local Land Services (LLS) in NSW?

Regional agency delivering biosecurity, NRM and agriculture support funded by rates and government grants.

What are the five classes of agricultural land capability most suitable for cultivation?

Classes I, II and III; classes IV & V are marginal or grazing only.

Which carbon-rich soil component improves structure, nutrient holding and water retention?

Organic matter (particularly humus).

Define ‘harvestable rights’ for farm dams in NSW.

Landholders may capture up to 10 % of average regional runoff without a licence for stock & domestic use.

Why is water turbidity a concern for irrigation?

Suspended sediments carry nutrients/pathogens, clog equipment and reduce light penetration for aquatic life.

Give one social tension that can arise from adopting GM crops.

Public concern over food safety or environmental ethics may affect market acceptance.

What is the main purpose of a buffer (grassed) waterway on farms?

Safely convey runoff, reducing erosion and filtering sediments/nutrients.

Which two hormones are used in oestrous synchronisation of cattle?

Progesterone (e.g. CIDR devices) and Prostaglandin injections.

What is hybrid vigour (heterosis)?

Enhanced performance of crossbred offspring over the average of their purebred parents.

Explain line breeding.

Mating animals that share a common ancestor to concentrate desirable genes while avoiding close inbreeding.

Which metabolic disease is caused by excessive lactic acid after sudden high-grain intake in cattle?

Grain poisoning (lactic acidosis).

Name two physical indicators of water quality most relevant to farmers.

Turbidity and colour (also temperature).

Identify one advantage and one disadvantage of minimum tillage.

Advantage: Conserves soil structure and moisture; Disadvantage: Greater reliance on herbicides.

What does FCR stand for, and why is it important?

Feed Conversion Ratio – kg feed per kg weight gain; indicates production efficiency.

Which infection causes brown stomach worm in cattle?

Ostertagia ostertagi.

What is compensatory growth and when does it occur?

Accelerated growth after a period of under-nutrition once adequate feed is resumed.

State one key ethical concern with live animal export.

Animal welfare during long-distance transport and overseas slaughter conditions.

List two major greenhouse gases released from agriculture.

Methane (CH₄) and nitrous oxide (N₂O).

Which precision tool measures soil moisture tension for irrigation scheduling?

Tensiometer.

Explain ‘whole-farm planning’.

Mapping and managing all land units according to capability to optimise production and conserve resources.

Give one reason why grazing legumes in a pasture mix benefits grasses.

Legumes fix nitrogen, which grasses utilise for faster growth.

What is the basic principle behind laser land levelling?

A rotating laser provides a reference plane so grading equipment achieves a uniform slope for irrigation.

Define ‘standard error’ in experimental results.

A measure indicating how far the sample mean is likely to be from the true population mean; used for significance testing.

Why is stem width an important trait in hay grading?

Thinner stems generally indicate higher digestibility and feed quality.

Name two benefits of computerised livestock record systems.

Improved traceability (compliance) and better data for management decisions (e.g. fertility, growth rates).

What does the term ‘precision agriculture’ imply?

Managing spatial variability within fields using technology (GPS, sensors) for site-specific input application.

Which drought strategy allows animals to maintain weight with lower feed cost: early weaning or late weaning?

Early weaning – calves/lambs require less feed than lactating mothers, reducing total feed demand.

What is the main goal of sustainable agriculture?

Meet current food/fibre needs without compromising the ability of future generations to meet theirs.

Give one environmental advantage of drip irrigation over flood irrigation.

Reduces water use and minimises salinity risk by applying water directly to the root zone.

What is the purpose of a National Vendor Declaration (NVD)?

Provides traceability and food-safety information when livestock are moved or sold.

State the five ‘rights’ of chemical application in farming.

Right product, right dose, right time, right place, right way (equipment).

Which entity co-funds rural research corporations with producer levies?

The Australian Government (matching funds up to 0.5 % of GVP).

Why are experimental controls essential?

They provide a baseline, allowing effects of treatments to be compared validly.

Identify two soil chemical tests commonly performed before planting.

Soil pH and available nitrate/phosphorus (nutrient status).

What is the primary economic rationale for vertical integration by a farming enterprise?

Capture a larger share of the consumer dollar by owning processing/marketing stages.

Which pasture species would you select for a salty, waterlogged paddock?

Saltbush or tall wheatgrass – salt-tolerant species.

Define ‘biosecurity’ in agriculture.

Measures to protect against entry and spread of pests, diseases and weeds that harm agriculture and the environment.

Mention one social benefit of cooperative farming enterprises.

Shared resources and knowledge strengthen community ties and support small producers.

What characteristic of C4 plants makes them better suited to hot, arid climates?

Their photosynthetic pathway minimises photorespiration, increasing water-use efficiency at high temperatures.

Name the two stages of photosynthesis.

Light (photo-) reactions and dark (Calvin cycle) reactions.

Why is leaf area index (LAI) important for crop growth?

Greater LAI increases total photosynthetic surface, boosting biomass accumulation until shading limits efficiency.

What is the purpose of a shelterbelt on livestock farms?

Provide windbreaks, reduce stress and energy loss in animals, increase pasture growth and biodiversity.