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VCE Agricultural and Horticultural Studies study materials
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VCE Agricultural and Horticultural Studies practice questions

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Question 1Agricultural and horticultural systems and production

Which soil property most directly determines the amount of plant-available water a soil can hold?

  1. Depth of the parent rock
  2. Soil texture and organic matter content Correct answer.
  3. Presence of earthworms
  4. Soil colour and slope position

Explanation

Plant-available water depends on pore size distribution, which is governed mainly by texture and by organic matter that increases aggregation and water-holding capacity. Colour, slope and parent rock depth affect other soil behaviours but not the water-holding capacity directly.

Question 2Agricultural and horticultural systems and production

A grower wants to reduce wind erosion on a bare, sandy paddock over summer. Which practice addresses the cause most directly?

  1. Deep ripping the paddock in spring
  2. Maintaining surface cover such as stubble or a cover crop Correct answer.
  3. Increasing irrigation frequency
  4. Applying nitrogen fertiliser before sowing

Explanation

Wind erosion occurs when bare, dry, loose soil particles are lifted by wind, so keeping the surface covered reduces the wind speed at the soil surface and anchors particles. Fertiliser, ripping and irrigation do not provide the physical protection that surface cover gives.

Question 3Agricultural and horticultural systems and production

In a legume–cereal rotation, the main agronomic benefit to the following cereal crop is:

  1. Elimination of all soil-borne pathogens
  2. Reduced need for phosphorus fertiliser
  3. Higher soil pH
  4. Increased nitrogen supply from legume residues Correct answer.

Explanation

Legumes form symbioses with rhizobia and fix atmospheric nitrogen, which is returned to the soil in roots and residues and becomes available to the following cereal. Phosphorus, pathogen control and pH are not automatically improved by the legume phase.

Question 4Agricultural and horticultural systems and production

Which of the following best describes the role of stomata in a crop leaf?

  1. They absorb mineral nutrients from the soil
  2. They regulate gas exchange and water loss Correct answer.
  3. They store starch for later use
  4. They transport sugars through the phloem

Explanation

Stomata are pores that open to allow carbon dioxide in for photosynthesis and oxygen out, while water vapour escapes through the same pores. Their opening and closing balances carbon gain against transpirational water loss.

Question 5Agricultural and horticultural systems and production

A farmer applies a herbicide that kills only the weeds present at spraying and leaves no residual soil activity. This herbicide is best described as:

  1. Contact or knockdown Correct answer.
  2. Systemic soil fumigant
  3. Residual pre-emergent
  4. Selective pre-plant incorporated

Explanation

A herbicide that acts on emerged weeds and breaks down quickly without leaving soil residues is a knockdown or contact-type product. Residual herbicides persist in soil to control weeds that germinate later.

Question 6Agricultural and horticultural systems and production

Which factor is the most important reason for maintaining a break between successive crops of the same species in a paddock?

  1. To increase the cation exchange capacity of the soil
  2. To encourage beneficial insects to leave the paddock
  3. To allow soil temperature to rise
  4. To reduce build-up of host-specific pests and diseases Correct answer.

Explanation

Many pathogens and pests survive in soil or residues and multiply when the same host species is grown repeatedly, so a break reduces their populations. Other factors such as temperature and exchange capacity are not managed by rotation in this way.

Question 7Agricultural and horticultural systems and production

In livestock production, the term 'feed conversion ratio' refers to:

  1. The kilograms of feed required per kilogram of liveweight gain Correct answer.
  2. The ratio of roughage to concentrate in a ration
  3. The percentage of a herd that requires supplementary feeding
  4. The proportion of pasture dry matter lost to trampling

Explanation

Feed conversion ratio expresses how efficiently an animal converts feed into body gain, calculated as feed consumed divided by liveweight gain. Lower values indicate more efficient conversion.

Question 8Agricultural and horticultural systems and production

Which practice is most likely to reduce nitrate leaching into groundwater beneath a horticultural crop?

  1. Leaving soil bare between crop rows
  2. Splitting nitrogen applications to match crop demand Correct answer.
  3. Irrigating heavily after each fertiliser application
  4. Applying all nitrogen fertiliser in a single dose before heavy rain

Explanation

Splitting nitrogen applications so that supply matches crop uptake reduces the amount of nitrate left in the soil when drainage occurs. Large single doses followed by heavy water input leave excess nitrate that can be leached.

Question 9Agricultural and horticultural systems and production

A crop shows interveinal yellowing on older leaves first, while veins remain green. Which nutrient deficiency is most consistent with these symptoms?

  1. Iron
  2. Boron
  3. Magnesium Correct answer.
  4. Calcium

Explanation

Magnesium is mobile in the plant, so when supply is short it is moved from older leaves to growing points, producing interveinal chlorosis on older leaves. Iron and calcium are largely immobile and show symptoms on new growth.

Question 10Agricultural and horticultural systems and production

A farmer wants to compare the yield of two wheat varieties under field conditions. Which experimental design element is most important to make the comparison reliable?

  1. Replicating each variety in several plots across the paddock Correct answer.
  2. Harvesting both varieties on the same day
  3. Applying the two varieties to large single strips
  4. Using the same seed rate for both varieties

Explanation

Replication across several plots allows natural variation in soil and microclimate to be averaged out, giving a more reliable estimate of the true difference between varieties. Single large strips confound variety with position in the paddock.

Question 11Agricultural and horticultural systems and production

Which statement best explains why a pasture containing a mixture of grasses and legumes is often more productive over a year than a grass-only pasture?

  1. Legumes supply fixed nitrogen and the species exploit different niches Correct answer.
  2. Grasses fix atmospheric nitrogen for the legumes
  3. Mixtures always have lower total water use
  4. Legumes shade the grasses and reduce competition

Explanation

Legumes contribute biologically fixed nitrogen to the sward, and the different rooting depths and growth patterns of grasses and legumes allow better use of water, light and nutrients across seasons. This complementarity supports more stable production.

Question 12Agricultural and horticultural systems and production

A soil test shows a pH of 4.8 in a paddock to be sown to a pH-sensitive crop. What is the most appropriate first action?

  1. Apply urea to acidify the surface further
  2. Deep rip the soil to mix the profile
  3. Apply lime and allow time for it to react before sowing Correct answer.
  4. Apply gypsum to raise pH immediately

Explanation

A pH of 4.8 is strongly acidic, and lime (calcium carbonate) is the standard amendment used to raise pH; it needs time and moisture to react through the soil. Gypsum supplies calcium and sulfur but does not raise pH.

Question 13Agricultural and horticultural systems and production

Integrated pest management (IPM) relies primarily on:

  1. Using only organic-approved products
  2. Combining monitoring, cultural controls and targeted chemicals when thresholds are reached Correct answer.
  3. Eliminating all insects from the crop
  4. Calendar spraying of broad-spectrum insecticides

Explanation

IPM combines monitoring, biological and cultural controls with chemical intervention only when pest numbers exceed an economic threshold, which slows resistance development and preserves natural enemies. Routine broad-spectrum spraying undermines these benefits.

Question 14Agricultural and horticultural systems and production

A dairy farmer increases stocking rate on the same area of pasture. Which outcome is most likely if supplementary feed is not increased?

  1. Reduced nutrient cycling through dung and urine
  2. Greater pasture utilisation per hectare but reduced per-animal intake Correct answer.
  3. Increased pasture residual and improved persistence
  4. Higher milk yield per cow with no added cost

Explanation

More animals on a fixed pasture area increases grazing pressure, so a greater proportion of grown pasture is harvested per hectare, but the feed available per animal falls unless supplements are supplied. This can reduce per-animal production and pasture persistence.

Question 15Agricultural and horticultural systems and production

Which irrigation scheduling approach makes most direct use of evaporation pan or weather data?

  1. Irrigating whenever the soil surface appears dry
  2. Irrigating only at night to reduce labour
  3. Replacing crop water use estimated from reference evapotranspiration and crop coefficients Correct answer.
  4. Scheduling on a fixed weekly interval

Explanation

Weather-based scheduling estimates crop water use from reference evapotranspiration adjusted by a crop coefficient, then applies water to replace that deficit. Fixed intervals and surface appearance are less reliable indicators of root-zone water status.

Question 16Agricultural and horticultural systems and production

A poultry producer notices eggshells becoming thin and cracked. Which dietary adjustment is most appropriate?

  1. Reduce protein to lower egg size
  2. Increase dietary fibre to slow passage
  3. Increase energy to raise body weight
  4. Increase calcium and available phosphorus to support shell formation Correct answer.

Explanation

Eggshell formation requires a steady supply of calcium and adequate available phosphorus and vitamin D for mineral metabolism, so thin shells often indicate a shortfall or imbalance of these nutrients. Fibre, protein and energy changes do not directly supply shell mineral.

Question 17Agricultural and horticultural systems and production

Which of the following best explains the benefit of controlled traffic farming?

  1. It allows deeper tillage across the whole paddock
  2. It eliminates the need for crop rotation
  3. It confines compaction to permanent wheel tracks so most of the soil remains uncompacted Correct answer.
  4. It increases the number of passes over the paddock

Explanation

Controlled traffic farming uses guidance to keep machinery wheels on the same permanent tracks, so compaction is confined to a small proportion of the paddock and the cropped soil retains better structure and infiltration. It does not remove the need for rotation or tillage.

Question 18Agricultural and horticultural systems and production

A grower observes that a block treated with a broad-spectrum insecticide has more aphids two weeks later than an untreated block. The most likely explanation is:

  1. The insecticide increased aphid reproduction directly
  2. Aphids became larger after treatment
  3. The untreated block had less nitrogen
  4. Natural enemies of aphids were reduced by the insecticide Correct answer.

Explanation

Broad-spectrum insecticides kill predatory and parasitic insects as well as pests, so aphid populations can rebound faster than their natural enemies and reach higher numbers. This resurgence effect is a recognised risk of non-selective sprays.

Question 19Agricultural and horticultural systems and production

In a crop rotation, a cereal is followed by a break crop and then by a cereal. Which principle does this sequence mainly exploit?

  1. Disruption of pathogen and weed life cycles between susceptible hosts Correct answer.
  2. Maintenance of a single soil microbial community
  3. Uniform depletion of all soil nutrients
  4. Continuous supply of the same root exudates

Explanation

Inserting a non-host break crop interrupts the build-up of cereal-specific pathogens and allows different weed control options, reducing pest and weed pressure before the next cereal. Continuous cropping of the same host would favour these problems.

Question 20Agricultural and horticultural systems and production

A sheep producer wants to reduce the risk of internal parasite populations becoming resistant to drench chemicals. Which strategy is most appropriate?

  1. Using combinations of drench groups and retaining some untreated animals as refugia Correct answer.
  2. Increasing stocking rate to dilute pasture contamination
  3. Drenching only the heaviest animals
  4. Drenching all animals frequently with the same product

Explanation

Resistance develops when surviving worms are repeatedly exposed to one chemical group, so rotating or combining groups and maintaining a population of susceptible worms in refugia slows selection. Frequent single-product drenching accelerates resistance.

Question 21Agricultural and horticultural systems and production

A vineyard on a sloping site shows poor vine vigour in a band across the mid-slope after heavy rain. Which explanation is most consistent with this pattern?

  1. Frost damage confined to the mid-slope
  2. Waterlogging or erosion where water accumulates or topsoil has been lost Correct answer.
  3. Nutrient deficiency caused by fertiliser placement in the row
  4. Herbicide drift from a neighbouring property

Explanation

Water moving down a slope can pond or concentrate in mid-slope bands, causing temporary waterlogging, and can also remove topsoil, both of which reduce root function and vine vigour. The banded pattern following heavy rain points to water movement rather than uniform fertiliser effects.

Question 22Agricultural and horticultural systems and production

A grower compares two nitrogen strategies: a single application of 150 kg N/ha at sowing versus 50 kg N/ha applied at three growth stages. Both supply the same total nitrogen. Which statement best explains why the split strategy may produce a higher yield?

  1. Split applications increase the crop's nitrogen requirement
  2. Single applications are absorbed more slowly by roots
  3. Split applications always increase total nitrogen uptake by leaching less
  4. Split applications better match supply to crop demand and reduce losses between stages Correct answer.

Explanation

Splitting nitrogen matches supply to the periods of greatest crop uptake, reducing the amount of nitrate exposed to leaching or denitrification between application and demand. A single early dose can leave excess nitrate vulnerable to loss before the crop needs it.

Question 23Agricultural and horticultural systems and production

A farmer uses a pasture phase in a cropping rotation. Which combination of benefits is most defensible?

  1. Permanent increase in soil pH
  2. Higher grain prices in the following season
  3. Improved soil structure and nitrogen supply, plus disruption of cereal disease cycles Correct answer.
  4. Guaranteed elimination of herbicide-resistant weeds

Explanation

Pasture phases add organic matter and root activity that improve structure and infiltration, legumes add nitrogen, and the change of host disrupts cereal disease and weed cycles. They do not guarantee weed elimination or change grain prices and pH permanently.

Question 24Agricultural and horticultural systems and production

A horticultural producer switches from overhead sprinklers to drip irrigation. Which outcome is most likely?

  1. Reduced water loss by evaporation and better placement of water in the root zone Correct answer.
  2. Greater wind erosion of inter-row soil
  3. Increased foliar disease because leaves stay wetter
  4. Higher leaching of nitrate below the root zone

Explanation

Drip irrigation delivers water directly to the root zone and keeps foliage dry, reducing evaporation and foliar disease while improving water use efficiency. Overhead sprinklers wet the whole canopy and soil surface, losing more water to evaporation.

Question 25Agricultural and horticultural systems and production

A producer wants to reduce methane emissions per kilogram of milk from a dairy herd. Which change is most likely to achieve this?

  1. Increasing the proportion of low-digestibility forage in the ration
  2. Improving forage digestibility and herd productivity per animal Correct answer.
  3. Extending the interval between calvings
  4. Reducing the frequency of feed analysis

Explanation

Methane is produced during rumen fermentation, and more digestible feed plus higher output per animal dilutes the methane emitted per kilogram of milk. Poorer quality forage and lower productivity increase emissions per unit of output.

Question 26Agricultural and horticultural systems and production

In a plant–soil system, which term describes the process by which legumes convert atmospheric nitrogen into forms usable by plants?

  1. Nitrification
  2. Biological nitrogen fixation Correct answer.
  3. Denitrification
  4. Mineralisation

Explanation

Biological nitrogen fixation is performed by rhizobia living in root nodules of legumes, which reduce atmospheric dinitrogen to ammonia that the plant can use. The other processes transform nitrogen already in the soil or return it to the atmosphere.

Question 27Agricultural and horticultural systems and production

Which soil property is most directly improved by adding organic matter such as compost or green manure to a sandy soil?

  1. Bulk density of the parent rock
  2. Depth to the watertable
  3. Soil pH
  4. Water-holding capacity Correct answer.

Explanation

Organic matter increases the soil's ability to retain moisture because humus and organic particles hold water that would otherwise drain rapidly through coarse sandy pores. It also supports aggregation and nutrient exchange, but its most immediate effect on a sandy soil is improved water retention.

Question 28Agricultural and horticultural systems and production

A producer wants to propagate a large number of genetically identical apple rootstocks quickly. Which technique is most suitable?

  1. Grafting seedling rootstocks
  2. Collecting open-pollinated seed
  3. Taking cuttings for vegetative propagation Correct answer.
  4. Cross-pollinating selected parents

Explanation

Vegetative propagation such as cuttings produces clones that carry the same genotype as the parent, so desirable rootstock traits are preserved exactly. Seed-based methods involve recombination and therefore produce variable offspring.

Question 29Agricultural and horticultural systems and production

Which animal production term describes the number of offspring born alive per female per reproductive cycle?

  1. Carcass dressing percentage
  2. Litter size Correct answer.
  3. Feed conversion ratio
  4. Weaning weight

Explanation

Litter size measures the number of live young produced by a female in one reproductive event, such as piglets per sow per farrowing. It is a key driver of reproductive efficiency in prolific species.

Question 30Agricultural and horticultural systems and production

Which practice best reduces soil erosion on a bare, sloping paddock during a wet winter?

  1. Removing contour banks
  2. Maintaining a cover crop or stubble cover Correct answer.
  3. Increasing cultivation frequency
  4. Deep ripping along the slope

Explanation

Ground cover intercepts raindrop energy, slows surface runoff and holds soil particles in place, which greatly reduces sheet and rill erosion. Bare cultivated soil is far more vulnerable to detachment and transport.

Question 31Agricultural and horticultural systems and production

In a greenhouse, which environmental factor is most commonly manipulated to control the rate of crop development and flowering time?

  1. Temperature Correct answer.
  2. Wind speed outside the structure
  3. Soil texture
  4. Atmospheric pressure

Explanation

Temperature governs the rate of plant development, including the accumulation of thermal time needed for flowering and maturity, so greenhouse managers adjust heating and ventilation to steer crop timing. Other listed factors are not practical or relevant controls inside a glasshouse.

Question 32Agricultural and horticultural systems and production

Which statement correctly describes the purpose of a market specification (such as a size grade) in horticultural supply chains?

  1. It sets the minimum quality and size criteria a product must meet to be sold into a market. Correct answer.
  2. It guarantees the farm will make a profit.
  3. It replaces the need for on-farm quality control.
  4. It determines the soil type required for production.

Explanation

Market specifications define measurable quality, size and presentation requirements so buyers receive consistent product and growers know what to target. Meeting a specification supports access to a market but does not guarantee financial returns.

Question 33Agricultural and horticultural systems and production

Which of the following is a renewable on-farm input that can reduce reliance on purchased fertiliser nitrogen?

  1. Single superphosphate
  2. Urea topdressing
  3. Legume-based pasture in the rotation Correct answer.
  4. Lime application

Explanation

Legume pastures host rhizobia that fix atmospheric nitrogen, which is then released to following crops when the pasture is grazed or incorporated. This biological source is regenerated each season and reduces dependence on bagged nitrogen.

Question 34Agricultural and horticultural systems and production

A cereal grower wants to reduce the risk of herbicide-resistant weeds developing in a paddock. Which strategy is most appropriate?

  1. Rotating herbicide groups and integrating non-chemical weed control Correct answer.
  2. Delaying all weed control until after seed set
  3. Using the same herbicide group every season at a reduced rate
  4. Applying the maximum label rate of one herbicide each year

Explanation

Resistance develops when the same mode of action is applied repeatedly, selecting survivors that carry resistance traits. Rotating herbicide groups and combining them with cultural controls such as cultivation, grazing or crop competition reduces selection pressure.

Question 35Agricultural and horticultural systems and production

A grower applies 200 kg/ha of a fertiliser containing 20% nitrogen. How much nitrogen is applied per hectare?

  1. 20 kg N/ha
  2. 100 kg N/ha
  3. 200 kg N/ha
  4. 40 kg N/ha Correct answer.

Explanation

The nitrogen applied equals the product rate multiplied by the nitrogen concentration: 200 kg/ha × 0.20 = 40 kg N/ha. This calculation is essential for matching application rates to crop demand.

Question 36Agricultural and horticultural systems and production

Which grazing management approach is most likely to improve pasture persistence in a perennial grass paddock that is currently continuously grazed?

  1. Grazing only during flowering
  2. Continuous heavy stocking all year
  3. Rotational grazing with adequate rest periods Correct answer.
  4. Increasing stocking rate without rest

Explanation

Rotational grazing gives plants rest periods to rebuild leaf area and root reserves, improving persistence and regrowth. Continuous heavy grazing depletes carbohydrate reserves and weakens plants over time.

Question 37Agricultural and horticultural systems and production

A fruit grower notices that bees are visiting flowers but fruit set is poor. Which factor should be investigated first?

  1. Whether the trees were pruned last winter
  2. Whether the cultivar requires cross-pollination with a compatible polleniser Correct answer.
  3. Whether the orchard has a windbreak
  4. Whether the soil pH is above 6.0

Explanation

Poor fruit set despite bee activity often indicates a pollination compatibility problem, such as self-incompatibility or missing polleniser rows. Checking cultivar compatibility and polleniser placement is the logical first step before considering other factors.

Question 38Agricultural and horticultural systems and production

Which change to a piggery is most likely to reduce the volume of effluent that must be stored and spread on land?

  1. Feeding a higher protein diet
  2. Separating clean stormwater from contaminated effluent Correct answer.
  3. Covering the effluent pond
  4. Increasing the amount of wash-down water used

Explanation

Keeping clean roof and stormwater separate from manure-contaminated water reduces the total volume requiring storage and disposal. This lowers pressure on pond capacity and land application areas.

Question 39Agricultural and horticultural systems and production

A producer wants to estimate the liveweight gain of steers over a 90-day period. Which measurement approach is most appropriate?

  1. Weighing each animal at the start and end of the period using the same scales Correct answer.
  2. Asking the buyer for a weight estimate
  3. Weighing animals once at the end of the period
  4. Estimating weight from photographs at the end of the period

Explanation

Liveweight gain is calculated as the difference between start and end weights divided by the number of days, so both measurements are required using consistent equipment. Weighing at the same time of day and under similar conditions improves accuracy.

Question 40Agricultural and horticultural systems and production

Which crop sequence is the best example of using a break crop to disrupt a soil-borne cereal disease cycle?

  1. Wheat followed by canola followed by wheat Correct answer.
  2. Wheat followed by barley followed by wheat
  3. Wheat followed by wheat followed by oats
  4. Barley followed by triticale followed by barley

Explanation

A non-host break crop such as canola interrupts the build-up of cereal-specific pathogens by depriving them of a host for a season. This reduces inoculum before cereals return to the paddock.

Question 41Agricultural and horticultural systems and production

A grower notices that a block treated with a broad-spectrum insecticide has more aphids two weeks later than an untreated block. Which explanation is most consistent with integrated pest management principles?

  1. The insecticide increased soil nitrogen availability
  2. The insecticide caused the aphids to mutate into a new species
  3. The untreated block had more rainfall
  4. The insecticide killed natural enemies, allowing aphid populations to rebound Correct answer.

Explanation

Broad-spectrum insecticides can remove predators and parasitoids that normally suppress aphids, leading to a secondary outbreak when the pest reproduces without regulation. This is a recognised risk that IPM seeks to avoid through selective products and monitoring.

Question 42Agricultural and horticultural systems and production

A grower is deciding whether to invest in a new irrigation system. Which financial indicator best shows the time required for cumulative net benefits to equal the initial investment?

  1. Return on assets
  2. Break-even yield
  3. Payback period Correct answer.
  4. Gross margin

Explanation

Payback period measures how long it takes for accumulated returns from an investment to recover its initial cost. It is a simple indicator of investment risk and liquidity.

Question 43Agricultural and horticultural systems and production

Which factor most directly limits photosynthesis in a well-watered, well-fertilised crop canopy on a hot, bright day?

  1. Low soil temperature
  2. Lack of soil phosphorus
  3. Absence of root hairs
  4. Stomatal closure reducing carbon dioxide supply Correct answer.

Explanation

On hot, bright days plants close stomata to conserve water, which restricts carbon dioxide entry and limits photosynthesis even when light is abundant. This trade-off between water conservation and carbon gain is a key limitation in field crops.

Question 44Agricultural and horticultural systems and production

A dairy farmer wants to reduce the risk of milk quality downgrades from mastitis. Which practice is most directly preventive?

  1. Increasing milking frequency to four times daily
  2. Milking cows with wet teats
  3. Feeding a higher grain ration
  4. Using teat disinfection and dry-cow therapy as part of a herd health plan Correct answer.

Explanation

Teat disinfection after milking and dry-cow therapy target the bacteria that cause intramammary infections, reducing new mastitis cases. These practices are core components of a herd mastitis control plan.

Question 45Agricultural and horticultural systems and production

A vegetable grower applies a pre-emergent herbicide but heavy rain follows within hours. Which outcome is most likely?

  1. The herbicide will become more effective on established weeds
  2. The herbicide will increase soil pH
  3. The herbicide may leach into the crop row and cause injury to germinating seedlings Correct answer.
  4. The herbicide will break down instantly and have no effect

Explanation

Pre-emergent herbicides form a soil layer that germinating weeds absorb; heavy rain soon after application can move the chemical into the crop's germination zone and injure seedlings. This is why label advice often restricts application before forecast heavy rain.

Question 46Agricultural and horticultural systems and production

A producer is comparing two feeding strategies for a broiler flock. Strategy A gives a lower-cost ration with a feed conversion ratio of 1.9; Strategy B gives a higher-cost ration with a feed conversion ratio of 1.7. Which analysis is most complete?

  1. Choose Strategy B because the ratio is lower
  2. Compare the total feed cost per kilogram of liveweight gain for each strategy Correct answer.
  3. Choose Strategy A because the ration costs less per tonne
  4. Choose Strategy A because a higher ratio means more efficient growth

Explanation

The economically correct comparison combines ration price with feed conversion ratio to calculate feed cost per kilogram of gain, since a cheaper ration may still cost more per unit of growth if efficiency is poorer. Comparing only price or only ratio gives an incomplete picture.

Question 47Agricultural and horticultural systems and production

A soil test shows a paddock has a high phosphorus buffering index (PBI). What does this most likely mean for phosphorus fertiliser management?

  1. Less phosphorus fertiliser is needed because phosphorus is readily available
  2. Phosphorus is not required by the planned crop
  3. More phosphorus fertiliser is needed because the soil strongly adsorbs phosphorus Correct answer.
  4. Phosphorus will leach rapidly below the root zone

Explanation

A high phosphorus buffering index indicates the soil strongly adsorbs phosphate onto clay and iron or aluminium surfaces, reducing its availability to plants. Higher application rates are therefore generally required to raise and maintain soil phosphorus levels.

Question 48Agricultural and horticultural systems and production

A horticultural producer is comparing open-field production with a greenhouse system. Which combination of trade-offs is most accurate?

  1. Open-field production always yields more per square metre than greenhouses
  2. Greenhouse production offers greater environmental control and higher yield per area but higher capital and energy costs Correct answer.
  3. Greenhouse production offers lower capital costs and lower yields per area
  4. Open-field production offers complete control over temperature and humidity

Explanation

Protected cropping allows temperature, humidity and pest exposure to be managed, which typically raises yield per square metre and extends seasons, but requires substantial capital and ongoing energy inputs. Open-field systems have lower infrastructure costs but depend on weather.

Question 49Agricultural and horticultural systems and production

A farmer observes that a paddock yields well in the first year after a long pasture phase but declines in subsequent cereal years. Which explanation best accounts for this pattern?

  1. The pasture phase built soil nitrogen and structure that are gradually depleted by successive cereals Correct answer.
  2. The pasture phase lowered the soil pH below the tolerance of cereals
  3. The pasture phase increased soil-borne cereal pathogens that persist for years
  4. The pasture phase reduced soil organic carbon permanently

Explanation

Legume-based pastures accumulate nitrogen and improve soil structure, giving the first cereal crop a boost; successive cereal crops draw down that nitrogen and organic matter, so yields tend to decline without replenishment. This is a well-recognised feature of ley farming systems.

Question 50Agricultural and horticultural systems and production

A cotton grower uses deficit irrigation to stretch a limited water allocation. Which outcome is most consistent with expected crop responses?

  1. Slight yield reduction with a proportionally larger saving in water use, if deficits are timed to tolerant stages Correct answer.
  2. Large yield increase due to improved water-use efficiency
  3. No change in yield regardless of the timing of deficits
  4. Complete crop failure whenever any deficit is applied

Explanation

Deficit irrigation deliberately applies less water than full requirements, often during growth stages that are less sensitive to stress, producing a modest yield penalty for a larger water saving. Timing is critical because stress during flowering or grain filling causes disproportionate losses.