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NCEA Level 2 Agricultural and Horticultural Science study materials
NCEA Level 2 Agricultural and Horticultural Science study resources

NCEA Level 2 Agricultural and Horticultural Science practice questions

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Question 1Agricultural and Horticultural Science (content domain unspecified in source)

A dairy farmer wants to reduce nitrate leaching into groundwater beneath a paddock that is grazed heavily in autumn. Which management practice is most likely to reduce leaching losses?

  1. Cultivating the paddock and leaving it fallow over winter
  2. Grazing the paddock to a very low residual cover before winter
  3. Deferring grazing so a plant cover remains over winter Correct answer.
  4. Applying nitrogen fertiliser immediately before heavy autumn rain

Explanation

An actively growing plant cover over winter takes up soil nitrate and holds it in plant tissue, reducing the amount that can be leached by drainage. Leaving a residual pasture cover also reduces the concentration of urinary nitrogen returned in one spot. Practices that add nitrogen or leave bare soil increase the risk of nitrate moving below the root zone.

Question 2Agricultural and Horticultural Science (content domain unspecified in source)

Which soil property is most directly improved by maintaining a high level of soil organic matter in a cropping paddock?

  1. Water-holding capacity and aggregate stability Correct answer.
  2. Soil pH measured in a water suspension
  3. The bulk density of the underlying parent rock
  4. The cation exchange capacity of the clay fraction only

Explanation

Organic matter binds soil particles into stable aggregates and holds water in pore spaces, so it improves both structure and water storage. These effects support root growth and reduce surface crusting and erosion. Organic matter does influence nutrient supply, but it does not directly set pH or alter parent rock density.

Question 3Agricultural and Horticultural Science (content domain unspecified in source)

A sheep farmer notices that ewes grazing pasture with a high proportion of perennial ryegrass show better liveweight gain in spring than ewes on older pasture dominated by browntop and sweet vernal. Which explanation best accounts for this difference?

  1. Ryegrass pastures have a lower stocking rate than older pastures
  2. Perennial ryegrass has a higher metabolisable energy and better spring growth than the resident species Correct answer.
  3. Older pasture species have a higher digestibility than ryegrass in spring
  4. Browntop and sweet vernal contain compounds that are toxic to sheep

Explanation

Improved pasture species such as perennial ryegrass are selected for high metabolisable energy, palatability and strong spring growth, so animals gain more liveweight per unit of dry matter eaten. Older resident species such as browntop and sweet vernal generally have lower feed value and slower early spring growth. The difference reflects feed quality and supply rather than toxicity or stocking rate.

Question 4Agricultural and Horticultural Science (content domain unspecified in source)

Which term describes the process by which a plant converts light energy into chemical energy stored in carbohydrates?

  1. Photosynthesis Correct answer.
  2. Respiration
  3. Translocation
  4. Transpiration

Explanation

Photosynthesis uses light energy, carbon dioxide and water to produce carbohydrates and oxygen in the chloroplasts. Respiration releases energy from those carbohydrates, transpiration is water loss through stomata, and translocation is the movement of sugars through the phloem.

Question 5Agricultural and Horticultural Science (content domain unspecified in source)

A grower wants to reduce the risk of clubroot in a brassica crop. Which practice is most effective as part of an integrated control programme?

  1. Increasing soil pH to 7.5 and above before planting
  2. Planting brassicas in the same block every season to build resistance
  3. Maintaining a long rotation with non-brassica crops and controlling brassica weeds Correct answer.
  4. Applying nitrogen fertiliser at double the recommended rate

Explanation

Clubroot is caused by a soil-borne organism that survives in soil and in brassica weeds, so a long break from brassica crops reduces the build-up of inoculum. Controlling brassica weeds removes alternative hosts. Raising pH can reduce disease severity but is not the primary control, and repeated brassica cropping increases inoculum.

Question 6Agricultural and Horticultural Science (content domain unspecified in source)

Which statement correctly describes the role of the rumen in a dairy cow?

  1. It stores bile produced by the liver
  2. It secretes hydrochloric acid that digests protein directly
  3. It absorbs most of the water from ingested feed
  4. It houses microbes that ferment fibrous plant material Correct answer.

Explanation

The rumen is a large fermentation chamber containing bacteria, protozoa and fungi that break down cellulose and other plant fibres the cow cannot digest with its own enzymes. The products are volatile fatty acids and microbial protein that the cow absorbs. Acid digestion occurs mainly in the abomasum, and water absorption is not the rumen's primary role.

Question 7Agricultural and Horticultural Science (content domain unspecified in source)

A farmer wants to estimate pasture dry matter on offer before setting a stocking rate. Which method is most appropriate?

  1. Estimating pasture height by eye from the gate
  2. Measuring the soil moisture content of the topsoil
  3. Cutting several quadrat samples to ground level and drying them Correct answer.
  4. Weighing a single handful of pasture cut from one spot

Explanation

Dry matter is measured by cutting samples of known area to grazing height, drying them to remove moisture, and then calculating dry matter per hectare. Several quadrats are needed to account for paddock variability. A single handful or a visual estimate is not representative, and soil moisture does not measure pasture mass.

Question 8Agricultural and Horticultural Science (content domain unspecified in source)

Which factor is most likely to cause a spike in somatic cell count in a dairy herd?

  1. A change from pasture to a crop diet
  2. An outbreak of mastitis in the herd Correct answer.
  3. Applying urea fertiliser to the paddock
  4. Reducing the herd's stocking rate

Explanation

Somatic cells are mainly white blood cells that increase in milk in response to udder infection, so a mastitis outbreak raises the bulk somatic cell count. Diet changes, stocking rate and fertiliser application do not directly cause the immune response measured by somatic cell count.

Question 9Agricultural and Horticultural Science (content domain unspecified in source)

A horticulturalist is selecting a rootstock for a new apple block on a site with heavy, poorly drained soil. Which rootstock characteristic is most important to consider?

  1. The colour of the fruit produced by the scion
  2. The number of branches on the nursery tree
  3. The sugar content of the previous season's fruit
  4. Tolerance of wet soil conditions and resistance to root diseases Correct answer.

Explanation

On poorly drained sites, root health determines whether the tree establishes and survives, so tolerance of wet soil and resistance to root rot are key rootstock traits. Rootstocks also control tree vigour and size, which affects management. Fruit colour and sugar content are scion traits and are not the main issue on a wet site.

Question 10Agricultural and Horticultural Science (content domain unspecified in source)

Which practice best reduces soil erosion on a steep, cultivated hillside?

  1. Planting contour strips of vegetation and using minimum tillage Correct answer.
  2. Removing all shelterbelts to increase airflow
  3. Leaving the soil bare over winter to dry out
  4. Ploughing up and down the slope to speed drainage

Explanation

Contour strips slow down runoff and trap soil moving downslope, and minimum tillage keeps cover and root structure that hold the soil. Together they reduce both sheet and rill erosion. Ploughing up and down the slope concentrates water flow and accelerates erosion, and bare soil is highly vulnerable.

Question 11Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why a legume such as white clover is valuable in a pasture mixture?

  1. It releases nitrogen into the soil by decomposing its roots each night
  2. It prevents all nitrogen leaching from the paddock
  3. It fixes atmospheric nitrogen through a symbiotic relationship with rhizobia Correct answer.
  4. It supplies nitrogen to the soil without needing any phosphorus

Explanation

Rhizobia bacteria in root nodules of legumes convert atmospheric nitrogen into forms the plant can use, and this nitrogen becomes available to the pasture when plant material and dung are broken down. This reduces reliance on nitrogen fertiliser. Legumes do not stop leaching and still require adequate phosphorus and other nutrients to grow well.

Question 12Agricultural and Horticultural Science (content domain unspecified in source)

A grower notices that a crop has pale yellow older leaves while newer leaves remain green. Which nutrient deficiency is most consistent with this pattern?

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

Explanation

Nitrogen is mobile in the plant, so when supply is short the plant moves nitrogen from older leaves to growing points, causing older leaves to yellow first. Iron and calcium are relatively immobile, so deficiency symptoms appear on young leaves. Boron deficiency also affects growing points rather than causing general yellowing of older leaves.

Question 13Agricultural and Horticultural Science (content domain unspecified in source)

What is the main purpose of applying lime to a pastoral soil?

  1. To increase soil nitrogen content directly
  2. To increase soil pH and supply calcium Correct answer.
  3. To kill pasture weeds selectively
  4. To improve soil drainage by opening pores

Explanation

Lime is calcium carbonate, which neutralises soil acidity and raises pH, and it also supplies calcium. Raising pH improves the availability of several nutrients and supports clover growth. Lime does not add nitrogen, change physical drainage, or act as a selective herbicide.

Question 14Agricultural and Horticultural Science (content domain unspecified in source)

A farmer is planning a winter grazing crop of fodder beet for dairy cows. Which consideration is most important to manage the risk of nitrate poisoning?

  1. Introduce the crop gradually and avoid feeding it to hungry stock Correct answer.
  2. Apply extra nitrogen fertiliser before grazing
  3. Feed the crop only after a hard frost has killed the leaves
  4. Feed the whole crop at once to reduce selective grazing

Explanation

Fodder beet and other forage crops can contain high levels of nitrate, and hungry stock eating large amounts quickly are at greatest risk of nitrate poisoning. Introducing the crop gradually and ensuring animals are not hungry reduces intake of the risky material. Extra nitrogen increases nitrate levels, and frost does not reliably make the crop safe.

Question 15Agricultural and Horticultural Science (content domain unspecified in source)

Which feature of a greenhouse best helps to control temperature on a hot, sunny day?

  1. Watering the floor to raise humidity to saturation
  2. Increasing the heating set point
  3. Using shade cloth and opening vents to increase ventilation Correct answer.
  4. Sealing all vents to trap cool air

Explanation

Shade cloth reduces incoming solar radiation, and opening vents allows hot air to escape and cooler outside air to enter. Together they lower the internal temperature and protect plants from heat stress. Sealing vents traps heat, and raising the heating set point adds more heat.

Question 16Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best describes the purpose of crop rotation in a vegetable production system?

  1. It removes the need for any fertiliser application
  2. It guarantees that no pests or diseases will occur
  3. It allows the same crop to be grown in the same bed each year
  4. It reduces the build-up of soil-borne pests and helps maintain soil fertility Correct answer.

Explanation

Rotating crops from different families breaks the life cycles of soil-borne pests and diseases that build up when one crop is grown repeatedly. Including legumes and returning organic matter can also help maintain soil fertility. Rotation reduces risk but cannot guarantee freedom from pests, and fertiliser is still needed to meet crop requirements.

Question 17Agricultural and Horticultural Science (content domain unspecified in source)

A beekeeper wants to improve pollination of a kiwifruit orchard. Which practice is most likely to increase pollination success?

  1. Applying insecticide during the middle of the day at flowering
  2. Reducing the number of male vines to zero
  3. Removing all flowering plants from around the orchard
  4. Placing hives in the orchard during flowering and providing adequate shelter Correct answer.

Explanation

Kiwifruit relies on insects, especially bees, to transfer pollen from male to female vines, so placing hives in the orchard during flowering increases pollinator numbers. Shelter helps bees forage in windy conditions. Removing flowering plants reduces forage, and spraying insecticide during flowering can kill pollinators.

Question 18Agricultural and Horticultural Science (content domain unspecified in source)

What is the main advantage of using biological control in an integrated pest management programme?

  1. It reduces pest populations through natural enemies with less reliance on chemicals Correct answer.
  2. It kills all insects in the crop immediately
  3. It works equally well on all pests regardless of species
  4. It eliminates the need to monitor pest numbers

Explanation

Biological control uses predators, parasites or pathogens to suppress pest populations, which can reduce the need for chemical sprays and their side effects. It is usually part of an integrated programme alongside monitoring and other tactics. It does not act instantly on all insects and is specific to particular pests.

Question 19Agricultural and Horticultural Science (content domain unspecified in source)

A farmer is comparing two paddocks: one with a long history of cropping and one that has been in permanent pasture. Which difference is most likely to affect soil structure?

  1. Soil structure is determined only by the parent rock and cannot change with management
  2. The cropped paddock is likely to have higher earthworm populations
  3. The cropped paddock is likely to have more organic matter and better aggregation
  4. The permanent pasture is likely to have more organic matter and better aggregation Correct answer.

Explanation

Permanent pasture builds organic matter through root turnover, litter and dung, and the dense root network plus earthworm activity promotes stable aggregates. Repeated cultivation in cropping reduces organic matter and can break down structure. Soil structure is strongly influenced by management, not only by parent material.

Question 20Agricultural and Horticultural Science (content domain unspecified in source)

Which practice is most appropriate for reducing the risk of facial eczema in sheep and cattle?

  1. Applying nitrogen fertiliser during warm, humid weather
  2. Increasing the amount of dead leaf litter in the pasture
  3. Monitoring spore counts and applying zinc supplementation when counts are high Correct answer.
  4. Grazing animals on the shortest pasture available

Explanation

Facial eczema is caused by a toxin from the fungus Pithomyces chartarum, which grows on dead pasture litter during warm, humid conditions. Monitoring spore counts allows farmers to act before animals are exposed, and zinc supplementation reduces the effect of the toxin. Reducing litter and avoiding practices that increase litter help lower risk.

Question 21Agricultural and Horticultural Science (content domain unspecified in source)

Which term describes the removal of a growing point to encourage branching in a young plant?

  1. Pruning
  2. Pinching Correct answer.
  3. Grafting
  4. Thinning

Explanation

Pinching is the removal of the soft growing tip of a shoot to break apical dominance and encourage side shoots, producing a bushier plant. Thinning removes whole plants to reduce competition, pruning removes larger wood, and grafting joins a scion to a rootstock.

Question 22Agricultural and Horticultural Science (content domain unspecified in source)

A grower wants to reduce water loss from a newly planted crop during a hot, windy period. Which practice is most effective?

  1. Applying a mulch and providing wind shelter Correct answer.
  2. Cultivating the soil to a fine, bare tilth
  3. Watering only at midday in full sun
  4. Increasing the nitrogen fertiliser rate

Explanation

Mulch reduces evaporation from the soil surface, and shelter lowers wind speed, which reduces transpiration and physical damage to young plants. Together they conserve water during a hot, windy period. Extra nitrogen and bare cultivated soil increase water demand and evaporation, and midday watering in full sun is less efficient.

Question 23Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why crossbreeding is used in commercial sheep production?

  1. It prevents all genetic variation in the flock
  2. It can combine desirable traits from different breeds and produce hybrid vigour Correct answer.
  3. It guarantees that all offspring will be identical
  4. It removes the need to select breeding animals

Explanation

Crossbreeding combines traits such as growth rate, fertility and carcass quality from different breeds, and the offspring often show hybrid vigour, which can improve performance. It does not make offspring identical and does not remove the need for selection of breeding stock.

Question 24Agricultural and Horticultural Science (content domain unspecified in source)

A crop of tomatoes is growing vigorously but producing very few flowers. Which factor is most likely to be responsible?

  1. Too much shade and excessive nitrogen Correct answer.
  2. A shortage of phosphorus in the soil
  3. Regular pruning of side shoots
  4. Low humidity and cool night temperatures

Explanation

Excessive nitrogen promotes vegetative growth at the expense of flowering and fruiting, and heavy shade reduces the light needed for flower initiation and fruit set. Balanced nutrition and good light are needed for reproductive growth. Phosphorus shortage and cool conditions usually reduce growth rather than cause lush plants with few flowers.

Question 25Agricultural and Horticultural Science (content domain unspecified in source)

Which practice is most likely to improve the efficiency of irrigation water use in a horticultural block?

  1. Scheduling irrigation using soil moisture monitoring and crop demand Correct answer.
  2. Flooding the block until water runs off the surface
  3. Irrigating only when plants show permanent wilting
  4. Applying water in small, frequent doses regardless of soil moisture

Explanation

Scheduling irrigation from soil moisture measurements and crop water demand applies water when the crop needs it and in the right amount, reducing waste from over-irrigation. Flooding to runoff and fixed small doses ignore actual demand. Waiting for permanent wilting causes yield loss that cannot be recovered.

Question 26Agricultural and Horticultural Science (content domain unspecified in source)

Which soil structure type is most desirable for horticultural crop production?

  1. Granular Correct answer.
  2. Massive
  3. Single grain
  4. Platy

Explanation

Granular structure consists of small, rounded aggregates that provide a good balance of large and small pores, supporting both drainage and water-holding capacity. This pore network allows roots to penetrate easily and air to move through the soil.

Question 27Agricultural and Horticultural Science (content domain unspecified in source)

Which process describes the conversion of ammonium to nitrate in the soil by bacteria?

  1. Nitrogen fixation
  2. Ammonification
  3. Denitrification
  4. Nitrification Correct answer.

Explanation

Nitrification is a two-step microbial process in which ammonium-oxidising bacteria convert ammonium to nitrite, and nitrite-oxidising bacteria convert nitrite to nitrate. Nitrate is the form most readily taken up by pasture and crop plants.

Question 28Agricultural and Horticultural Science (content domain unspecified in source)

A farmer is considering using a catch crop after harvesting a maize silage paddock. What is the main purpose of a catch crop in this situation?

  1. To fix atmospheric nitrogen for the following pasture
  2. To raise soil pH before the next crop is sown
  3. To capture residual soil nitrate and reduce leaching over winter Correct answer.
  4. To break the life cycle of root-knot nematodes

Explanation

A catch crop such as oats or annual ryegrass is sown quickly after harvest to take up nitrate left in the soil profile, preventing it from being leached below the root zone during wet winter months. The nitrogen is then recycled when the crop is grazed or incorporated.

Question 29Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why a fine seedbed is prepared for small-seeded crops such as carrots?

  1. Fine tilth prevents the emergence of weeds around the seedlings
  2. Fine tilth increases the soil bulk density to hold moisture
  3. Fine tilth improves contact between the small seed and moist soil, aiding germination Correct answer.
  4. Fine tilth raises soil temperature to above 25 degrees Celsius

Explanation

Small seeds have limited stored reserves and must germinate quickly, so they require close contact with moist soil particles to absorb water. A fine, firm seedbed provides this contact and avoids large air pockets that would dry the seed out.

Question 30Agricultural and Horticultural Science (content domain unspecified in source)

A dairy farmer wants to increase the metabolisable energy content of a pasture-based diet for early-lactation cows. Which supplementary feed is the most concentrated source of metabolisable energy per kilogram of dry matter?

  1. Kale forage
  2. Hay
  3. Pasture silage
  4. Barley grain Correct answer.

Explanation

Cereal grains such as barley are high in starch and typically contain around 12 to 13 megajoules of metabolisable energy per kilogram of dry matter. This is much higher than conserved forages such as silage, hay or kale.

Question 31Agricultural and Horticultural Science (content domain unspecified in source)

Which term describes the interval from conception to birth in a farm animal?

  1. Lactation length
  2. Gestation period Correct answer.
  3. Service period
  4. Weaning interval

Explanation

The gestation period is the length of pregnancy from conception to parturition. Its duration is characteristic of the species, for example about 283 days in cattle and about 147 days in sheep.

Question 32Agricultural and Horticultural Science (content domain unspecified in source)

A farmer is handling cattle in a race and wants to reduce stress on the animals. Which practice is most likely to achieve this?

  1. Loud vocal commands to speed up movement
  2. Loading animals in the heat of the afternoon
  3. Moving animals slowly with quiet handling and clear flight-zone pressure Correct answer.
  4. Using electric prodders whenever animals hesitate

Explanation

Cattle are prey animals with a wide flight zone, so calm, low-stress handling using pressure and release encourages movement without fear. Quiet handling reduces bruising, injuries and stress hormones.

Question 33Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best describes the role of a shelterbelt on a pastoral farm?

  1. It increases soil nitrogen through nitrogen fixation by its roots
  2. It prevents all rainfall from reaching the paddock behind it
  3. It raises the water table beneath the paddock
  4. It reduces wind speed, lowering evaporation and reducing chill stress on stock Correct answer.

Explanation

A shelterbelt slows wind speed in the lee of the trees, which reduces evaporation from soil and pasture and lessens wind chill on livestock. This can improve pasture growth and animal welfare, especially in exposed regions.

Question 34Agricultural and Horticultural Science (content domain unspecified in source)

A grower notices that a block of lettuce has leaves with brown, scorched margins on older leaves while the growing point remains healthy. Which nutrient deficiency is most consistent with this symptom?

  1. Potassium Correct answer.
  2. Manganese
  3. Nitrogen
  4. Iron

Explanation

Potassium is mobile within the plant, so deficiency symptoms appear first on older leaves as marginal scorch or necrosis because the plant moves potassium to new growth. Iron and manganese are immobile, so their deficiencies show on young leaves.

Question 35Agricultural and Horticultural Science (content domain unspecified in source)

Which practice best reduces nitrate leaching from a grazed pasture paddock during winter?

  1. Cultivating the paddock to increase aeration
  2. Applying nitrogen fertiliser just before heavy rain
  3. Deferred grazing and avoiding nitrogen application in late autumn Correct answer.
  4. Grazing at high stocking density on wet soils

Explanation

Deferred grazing reduces the amount of urine and dung deposited during the high-risk wet period, and avoiding late-autumn nitrogen application limits the nitrate available to leach. Together these practices reduce the amount of nitrate moving below the root zone.

Question 36Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why a crop of peas is often included in a rotation before a cereal crop?

  1. Peas raise soil pH to neutral levels
  2. Peas increase soil bulk density to improve drainage
  3. Peas leave residual nitrogen in the soil that can benefit the following cereal Correct answer.
  4. Peas are immune to all soil-borne diseases

Explanation

Peas are legumes that form symbiotic associations with Rhizobium bacteria, fixing atmospheric nitrogen. When the pea crop residues break down, some of this nitrogen becomes available to the following cereal crop, reducing fertiliser requirements.

Question 37Agricultural and Horticultural Science (content domain unspecified in source)

A horticulturalist is planning an integrated pest management programme in a glasshouse. Which action is the first step in an effective IPM programme?

  1. Releasing predators before any pest is detected
  2. Applying a broad-spectrum insecticide on a weekly schedule
  3. Removing all beneficial insects to simplify control
  4. Monitoring and identifying pests to establish action thresholds Correct answer.

Explanation

IPM begins with regular monitoring and correct identification of pests so that action thresholds can be set. Control measures, including biological or chemical options, are only applied when pest numbers justify them.

Question 38Agricultural and Horticultural Science (content domain unspecified in source)

Which factor most directly determines the stocking rate a pasture can support over winter?

  1. The age of the pasture sward
  2. The number of paddocks on the farm
  3. The amount of pasture dry matter available per animal Correct answer.
  4. The average weight of the bulls on the farm

Explanation

Stocking rate must be matched to feed supply, and pasture dry matter available per animal is the key measure of that supply. If demand exceeds supply, animal performance and pasture persistence decline.

Question 39Agricultural and Horticultural Science (content domain unspecified in source)

Which practice is most likely to reduce the incidence of mastitis in a dairy herd?

  1. Teat spraying immediately after every milking Correct answer.
  2. Leaving cows standing in muddy yards after milking
  3. Milking cows with wet teats
  4. Sharing teat cups between cows without backflushing

Explanation

Post-milking teat disinfection kills bacteria on the teat skin while the teat canal is still open, reducing the chance of infection entering the udder. This is a core component of a mastitis control programme.

Question 40Agricultural and Horticultural Science (content domain unspecified in source)

A farmer notices that a mob of lambs has pale mucous membranes and poor growth despite adequate pasture. Which condition is most consistent with these signs?

  1. Ryegrass staggers
  2. Facial eczema
  3. Internal parasite burden Correct answer.
  4. Nitrate poisoning

Explanation

Pale mucous membranes and poor growth in young stock are classic signs of anaemia caused by blood-feeding internal parasites such as barber's pole worm. Faecal egg counts and drenching history would help confirm the diagnosis.

Question 41Agricultural and Horticultural Science (content domain unspecified in source)

Which term describes the practice of sowing a crop directly into the residue of the previous crop without cultivation?

  1. Conventional tillage
  2. Rotary hoeing
  3. No-till drilling Correct answer.
  4. Mouldboard ploughing

Explanation

No-till drilling places seed directly into undisturbed soil through the residue of the previous crop. It conserves soil moisture, reduces erosion and preserves soil structure compared with full cultivation.

Question 42Agricultural and Horticultural Science (content domain unspecified in source)

A grower wants to store harvested onions for several months. Which practice is most important to reduce storage rots?

  1. Storing onions in sealed plastic bags
  2. Harvesting onions when the necks are still green and thick
  3. Storing onions in a humid, warm shed
  4. Curing onions in warm, dry air before storage Correct answer.

Explanation

Curing allows the neck and outer skin to dry, forming a seal that resists rot organisms. Onions should then be stored cool and dry with good air movement to maintain quality.

Question 43Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why a greenhouse crop may benefit from supplementary carbon dioxide enrichment?

  1. Carbon dioxide eliminates the need for pollination
  2. Carbon dioxide raises the temperature inside the greenhouse
  3. Carbon dioxide reduces the need for irrigation water
  4. Carbon dioxide is a substrate for photosynthesis, so higher levels can increase growth when light is adequate Correct answer.

Explanation

Photosynthesis uses carbon dioxide as a substrate, and in a closed greenhouse the concentration can fall below ambient during active growth. Enrichment raises the rate of photosynthesis and can increase yield, provided light and other factors are not limiting.

Question 44Agricultural and Horticultural Science (content domain unspecified in source)

Which practice is most likely to improve soil organic matter in a long-term cropping paddock?

  1. Repeatedly cultivating the soil to a fine tilth
  2. Returning crop residues and adding compost or green manure crops Correct answer.
  3. Burning crop residues after harvest
  4. Leaving the soil bare over winter

Explanation

Organic matter builds when carbon inputs from residues, compost or green manures exceed losses. Retaining residues and adding organic materials increases soil carbon over time, improving structure and water-holding capacity.

Question 45Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best describes transpiration in a pasture plant?

  1. The movement of sugars through the phloem
  2. The loss of water vapour from leaf surfaces through stomata Correct answer.
  3. The conversion of light energy into chemical energy
  4. The uptake of nutrients by root hairs

Explanation

Transpiration is the evaporation of water from the moist surfaces of leaf cells into the air spaces and out through stomata. It drives the upward movement of water and nutrients in the xylem and cools the leaf.

Question 46Agricultural and Horticultural Science (content domain unspecified in source)

A farmer is deciding whether to apply nitrogen fertiliser to a pasture paddock in early spring. Which information would be most useful in making that decision?

  1. The breed of cattle grazing the paddock
  2. The colour of the farm buildings
  3. The number of years the paddock has been in pasture
  4. The soil temperature and the pasture growth rate compared with feed demand Correct answer.

Explanation

Nitrogen response depends on soil temperature and the pasture's ability to grow, so growth rate and feed demand indicate whether extra nitrogen will be used efficiently. Applying nitrogen when growth is slow or feed is surplus wastes money and increases leaching risk.

Question 47Agricultural and Horticultural Science (content domain unspecified in source)

Which practice best protects a stream from nutrient and sediment runoff on a dairy farm?

  1. Draining a wetland adjacent to the stream
  2. Applying effluent to saturated soil near the stream
  3. Fencing off a riparian buffer zone and planting it with natives Correct answer.
  4. Grazing stock right up to the streambank

Explanation

A fenced and planted riparian buffer intercepts runoff, traps sediment and takes up nutrients before they reach the stream. Excluding stock also prevents bank damage and direct faecal contamination.

Question 48Agricultural and Horticultural Science (content domain unspecified in source)

Which statement best explains why crossbred ewes are often used as the maternal flock in commercial sheep production?

  1. Crossbred ewes always produce leaner meat than purebreds
  2. Crossbred ewes show hybrid vigour, giving better fertility and lamb survival Correct answer.
  3. Crossbred ewes are immune to internal parasites
  4. Crossbred ewes do not require shearing

Explanation

Hybrid vigour from crossing breeds can improve fertility, mothering ability and lamb survival in the maternal flock. These traits are then complemented by a terminal sire chosen for growth and carcass quality.

Question 49Agricultural and Horticultural Science (content domain unspecified in source)

A grower is planning to plant a new block of apple trees on a site with a history of replant disease. Which practice is most appropriate to reduce the risk?

  1. Applying extra nitrogen fertiliser at planting
  2. Pruning the new trees heavily after planting
  3. Fumigating the soil or planting a break crop before replanting Correct answer.
  4. Planting the new trees immediately into the old tree holes

Explanation

Replant disease is caused by a build-up of soil-borne pathogens and poor soil biology in old orchard soil. Fumigation or a break crop before replanting reduces the pathogen load and allows new trees to establish better.

Question 50Agricultural and Horticultural Science (content domain unspecified in source)

Which practice is most likely to reduce the risk of nitrate poisoning in cattle grazing a forage crop?

  1. Introducing cattle to the crop gradually and providing a roughage supplement Correct answer.
  2. Grazing the crop after a period of drought stress
  3. Grazing the crop when it is young and growing rapidly
  4. Applying nitrogen fertiliser immediately before grazing

Explanation

Nitrate accumulates in rapidly growing or stressed plants and can overwhelm the rumen's conversion to nitrite and then ammonia. Gradual introduction and roughage feeding slow intake and support rumen function, reducing risk.