I85PREP
⌘ K
NCEA Level 3 Ag & Hort Science study materials
NCEA Level 3 Ag & Hort Science study resources

NCEA Level 3 Ag & Hort Science practice questions

One question at a time. Build your NCEA Level 3 Ag & Hort Science understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

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

In New Zealand pastoral farming, which clover species is most commonly used in sheep and beef pasture mixes because of its high nitrogen fixation and summer growth?

  1. Strawberry clover (Trifolium fragiferum)
  2. Red clover (Trifolium pratense)
  3. White clover (Trifolium repens) Correct answer.
  4. Subterranean clover (Trifolium subterraneum)

Explanation

White clover is the standard legume in New Zealand sheep and beef pastures because it spreads by stolons, tolerates close grazing, and fixes substantial nitrogen. Red clover is used mainly for silage and short-term leys, while subterranean and strawberry clovers suit drier or saline conditions.

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

A soil test reports a pH of 5.2 for a dairy pasture on a yellow-brown loam. What is the most appropriate management response?

  1. Apply superphosphate to raise pH
  2. Do nothing, because pH 5.2 is ideal for ryegrass and clover
  3. Apply lime to raise pH towards the target range for the soil and pasture species Correct answer.
  4. Apply gypsum to lower pH

Explanation

At pH 5.2, aluminium and manganese can become more soluble and reduce root growth, while phosphorus availability declines. Applying lime raises pH toward the target range (often about 5.8 to 6.0 for pasture), improving nutrient availability and legume performance.

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

Which process converts ammonium nitrogen to nitrate nitrogen in aerated agricultural soils?

  1. Leaching
  2. Volatilisation
  3. Nitrification Correct answer.
  4. Denitrification

Explanation

Nitrification is the microbial oxidation of ammonium to nitrite and then nitrate, carried out by bacteria in well-aerated soil. It makes nitrogen available for plant uptake but also makes nitrate vulnerable to leaching and denitrification.

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

What is the main purpose of pre-graze topping or controlling pasture residuals in a rotational grazing system?

  1. To raise the pasture's fibre content
  2. To reduce earthworm populations
  3. To maintain pasture quality and encourage tiller regrowth Correct answer.
  4. To increase the seed set of ryegrass

Explanation

Controlling residuals prevents seed head formation and dead material buildup, keeping pasture leafy and digestible. Leaving a consistent residual also supports rapid tiller regrowth and protects the base of the plant.

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

In a sheep breeding programme, what does 'scanning' (pregnancy scanning) primarily provide?

  1. The carcass weight of the ewe
  2. The wool micron of the ewe
  3. The number of fetuses and therefore expected lambing percentage Correct answer.
  4. The genetic merit of the ram

Explanation

Pregnancy scanning uses ultrasound to determine how many fetuses each ewe is carrying, allowing feed and management to be targeted. It gives an early estimate of lambing percentage and helps identify dry ewes.

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

Which factor most directly limits pasture growth on a dryland hill country farm during a typical summer dry period?

  1. Excessive soil aeration
  2. Soil moisture deficit Correct answer.
  3. Low soil temperature
  4. Excess soil nitrogen

Explanation

During summer dry spells, soil moisture falls below the level needed for plant growth, and pasture growth slows or stops. This moisture deficit is the primary limit in dryland systems where irrigation is unavailable.

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

Which horticultural practice best reduces the risk of disease carry-over between successive crops of the same species?

  1. Applying nitrogen fertiliser after harvest
  2. Continuous cropping of the same species
  3. Crop rotation with unrelated plant families Correct answer.
  4. Increasing plant density

Explanation

Many pathogens survive in soil or crop debris and are host-specific, so rotating to an unrelated plant family breaks the disease cycle. Continuous cropping of the same species allows pathogen populations to build up.

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

Which of the following is a key advantage of biological nitrogen fixation by legumes in a mixed pasture?

  1. It prevents pasture pests
  2. It eliminates the need for trace elements
  3. It increases soil phosphorus content
  4. It reduces the need for nitrogen fertiliser inputs Correct answer.

Explanation

Legumes form symbiotic relationships with rhizobia that convert atmospheric nitrogen into forms plants can use, reducing reliance on nitrogen fertiliser. The fixed nitrogen also becomes available to companion grasses through cycling of plant material and excreta.

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

A dairy farmer wants to reduce nitrogen leaching from a winter forage crop grazed in situ. Which practice is most effective?

  1. Grazing the crop in smaller breaks with back-fencing and stand-off of stock Correct answer.
  2. Increasing stocking rate during winter
  3. Applying nitrogen fertiliser immediately before grazing
  4. Grazing the whole crop in one break

Explanation

Small breaks with back-fencing limit the area being trampled and urine-patched at any one time, and stand-off keeps animals off wet soils. Together these reduce the concentration of urinary nitrogen deposited and the risk of drainage losses.

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

In a kiwifruit orchard, why is artificial pollination sometimes used alongside bees?

  1. To increase the number of male vines needed
  2. To improve fruit size and uniformity when bee activity is limited Correct answer.
  3. To reduce the number of flowers produced
  4. To prevent fruit drop caused by frost

Explanation

Kiwifruit set depends on adequate pollen transfer, and cool or wet weather can reduce bee activity. Supplementary artificial pollination increases seed set, which is strongly linked to fruit size and uniformity.

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

Which statement best explains why a pasture sward dominated by ryegrass can decline in quality during late spring?

  1. Ryegrass stops photosynthesising in warm weather
  2. Rapid reproductive growth produces stem and seed head, lowering digestibility Correct answer.
  3. Clover outcompetes ryegrass in spring
  4. Soil nitrogen falls below zero

Explanation

In late spring, ryegrass shifts from vegetative to reproductive growth, producing stems and seed heads that are higher in fibre and lower in digestibility. Managing grazing to control this reproductive growth maintains quality.

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

A grower notices yellowing between the veins of young tomato leaves while veins remain green. Which nutrient deficiency is most likely?

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

Explanation

Interveinal chlorosis on young leaves is a classic sign of iron deficiency, because iron is relatively immobile in the plant and new growth shows symptoms first. Nitrogen and phosphorus deficiencies tend to affect older leaves first.

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

Which management practice best reduces nitrate leaching after a winter-grazed kale crop is finished?

  1. Leaving the ground fallow over winter
  2. Cultivating the soil repeatedly
  3. Applying urea to the paddock
  4. Establishing a fast-growing catch crop to take up residual nitrogen Correct answer.

Explanation

A catch crop sown after grazing takes up residual soil nitrogen, holding it in plant tissue over winter and reducing drainage losses. Fallowing leaves nitrogen vulnerable to leaching in high-rainfall periods.

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

In a sheep flock, what is the main reason for 'flushing' ewes before mating?

  1. To synchronise lambing with shearing
  2. To reduce the need for pregnancy scanning
  3. To increase ovulation rate and therefore potential lambing percentage Correct answer.
  4. To increase wool growth during pregnancy

Explanation

Flushing means improving ewe nutrition in the weeks before mating, which can increase ovulation rate and the number of lambs born. It is a nutritional tool for lifting reproductive performance.

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

What is the primary role of a shelterbelt on a New Zealand pastoral or horticultural property?

  1. Increasing soil pH
  2. Increasing rainfall
  3. Reducing wind speed to protect stock, crops and pasture Correct answer.
  4. Eliminating all pasture pests

Explanation

Shelterbelts reduce wind speed, lowering evaporation, protecting young plants and reducing stress on livestock. The sheltered zone improves pasture growth and reduces damage to horticultural crops.

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

A soil test shows high Olsen P and low sulphate sulfur on a dairy farm. Which fertiliser choice best addresses the sulfur deficiency while avoiding further phosphorus buildup?

  1. Superphosphate
  2. Diammonium phosphate
  3. Elemental sulfur or ammonium sulphate Correct answer.
  4. Lime

Explanation

When phosphorus is already adequate, applying more superphosphate would add unnecessary phosphorus. Elemental sulfur or ammonium sulphate supplies sulfur without adding phosphorus, matching the soil test result.

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

Which statement about the relationship between feed quality and animal performance in a pasture system is most accurate?

  1. Higher metabolisable energy and lower fibre generally support higher liveweight gain Correct answer.
  2. Feed quality is irrelevant for young stock
  3. Higher fibre always increases liveweight gain
  4. Metabolisable energy has no effect on milk production

Explanation

Metabolisable energy concentration and fibre content determine how much energy an animal can extract and how quickly feed passes through the rumen. Leafy, higher-energy pasture generally supports greater liveweight gain and milk production.

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

In an integrated pest management programme for an orchard, what is the role of monitoring (e.g. pheromone traps)?

  1. To increase fruit size
  2. To kill all pests directly
  3. To replace all chemical controls permanently
  4. To determine pest pressure and time interventions appropriately Correct answer.

Explanation

Monitoring provides information on pest presence and population trends, allowing growers to act only when thresholds are reached. This reduces unnecessary sprays and improves timing of control.

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

Why does applying nitrogen fertiliser to a pasture in late autumn increase the risk of nitrogen loss compared with spring application?

  1. Warmer soils increase denitrification to zero
  2. Lower plant uptake and higher drainage reduce nitrogen use efficiency Correct answer.
  3. Nitrogen fertiliser becomes insoluble in cold soils
  4. Plants absorb more nitrogen in late autumn

Explanation

In late autumn, declining temperatures slow plant growth and nitrogen uptake, while rainfall and drainage increase. The combination means more of the applied nitrogen is left in the soil and vulnerable to leaching.

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

Which statement best describes the effect of treading damage (pugging) by cattle on wet pasture soils?

  1. It reduces soil porosity and pasture regrowth, increasing runoff and nutrient loss Correct answer.
  2. It improves soil aeration and drainage
  3. It has no effect on soil physical properties
  4. It increases pasture growth immediately

Explanation

Pugging compacts and smears the soil surface, destroying pore space and reducing water infiltration. This lowers pasture regrowth and increases runoff, sediment and nutrient loss to waterways.

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

A vineyard manager wants to reduce botrytis bunch rot risk in a humid region. Which combination of practices is most appropriate?

  1. Applying nitrogen to encourage dense growth
  2. Increasing canopy density and overhead irrigation
  3. Canopy management to improve airflow plus timely fungicide programmes Correct answer.
  4. Delaying harvest indefinitely

Explanation

Botrytis thrives in humid, still microclimates around bunches. Opening the canopy by leaf removal or shoot positioning improves airflow and reduces humidity, and fungicides timed to risk periods add further protection.

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

In a breeding programme, a ram has a high breeding value for growth but a high breeding value for dags (faecal contamination). How should a breeder interpret this?

  1. Selecting only on growth may increase dags, so a balanced selection index is needed Correct answer.
  2. Growth and dags are always favourably correlated
  3. Breeding values are not heritable
  4. High dag breeding value automatically improves growth

Explanation

Breeding values estimate genetic merit for each trait, and unfavourable genetic correlations mean selecting hard on one trait can worsen another. Using a selection index that weights multiple traits balances gain against undesirable side effects.

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

A dairy farm's nitrogen budget shows high imported supplement and fertiliser nitrogen with low nitrogen use efficiency. Which change is most likely to improve nitrogen use efficiency without reducing milk production?

  1. Applying all nitrogen fertiliser in winter
  2. Increasing both fertiliser nitrogen and supplement nitrogen
  3. Removing clover from the pasture
  4. Matching nitrogen inputs more closely to pasture growth and reducing surplus supplement Correct answer.

Explanation

Nitrogen use efficiency improves when inputs are matched to plant and animal demand, reducing surplus nitrogen that is vulnerable to loss. Trimming excess supplement and aligning fertiliser with growth periods lowers losses while maintaining feed supply.

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

Which explanation best accounts for the benefit of a diverse pasture mix (e.g. ryegrass, clover, plantain, chicory) in a dryland system?

  1. Diversity eliminates the need for grazing management
  2. All species have identical growth requirements
  3. Diverse mixes always have lower nutritive value
  4. Different species have complementary growth rhythms and rooting depths, buffering feed supply Correct answer.

Explanation

Species differ in seasonal growth, drought tolerance and root depth, so a diverse mix can maintain feed supply when conditions suit some species but not others. This complementarity buffers against seasonal variability.

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

A grower is deciding whether to use a cover crop between vegetable crops. Which reasoning best reflects the agronomic trade-offs?

  1. Cover crops have no effect on soil biology
  2. Cover crops eliminate the need for fertiliser in all cases
  3. Cover crops always increase the following crop's yield regardless of management
  4. Cover crops can improve soil structure and suppress weeds but must be managed to avoid water and nitrogen competition with the following crop Correct answer.

Explanation

Cover crops can build organic matter, improve structure and suppress weeds, but they also use water and nitrogen. Termination timing and species choice determine whether benefits outweigh competition with the following cash crop.

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

In a ryegrass–white clover pasture, which process converts atmospheric nitrogen into a plant-available form within the root nodules?

  1. Biological nitrogen fixation by Rhizobium bacteria Correct answer.
  2. Mineralisation by saprophytic fungi
  3. Denitrification by Pseudomonas bacteria
  4. Nitrification by Nitrosomonas bacteria

Explanation

Rhizobium bacteria live symbiotically inside legume root nodules and use the enzyme nitrogenase to reduce atmospheric N2 to ammonia, which the plant can use. The other processes act on nitrogen already present in the soil rather than converting atmospheric gas.

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

A soil test reports a pH of 5.2 for a pastoral paddock. Which effect on nutrient availability is most likely?

  1. Reduced risk of aluminium toxicity to roots
  2. Increased availability of phosphorus and molybdenum
  3. Increased uptake of calcium by pasture plants
  4. Reduced availability of phosphorus and molybdenum Correct answer.

Explanation

In strongly acid soils, phosphorus becomes bound by aluminium and iron compounds and molybdenum availability declines, while aluminium toxicity risk rises. Liming raises pH and improves availability of these nutrients.

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

Which grazing management approach best maintains pasture quality and persistence in a ryegrass–clover sward?

  1. Grazing to a consistent residual and allowing adequate regrowth Correct answer.
  2. Continuous set-stocking at a low pasture residual
  3. Removing all stock during active spring growth
  4. Grazing only when seed heads have fully matured

Explanation

Rotational grazing to a target residual prevents shading of tillers and allows reserves to rebuild before the next grazing, maintaining quality and persistence. Continuously hard-grazing or letting pasture mature both reduce quality.

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

Which factor most directly determines the digestibility of pasture eaten by grazing livestock?

  1. The mineral content of the herbage
  2. The crude protein content of the herbage
  3. The moisture content of the herbage
  4. The fibre (neutral detergent fibre) content of the herbage Correct answer.

Explanation

Digestibility is largely governed by fibre content, since lignin and structural carbohydrates resist microbial breakdown in the rumen. As pasture matures, fibre rises and digestibility falls.

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

In a horticultural orchard, which practice best reduces the build-up of pests and diseases between seasons?

  1. Applying the same protectant fungicide on a fixed calendar
  2. Removing and destroying prunings and fallen fruit Correct answer.
  3. Increasing plant density to shade the orchard floor
  4. Irrigating overhead during the evening

Explanation

Removing and destroying prunings and fallen fruit breaks the carry-over cycle by eliminating overwintering inoculum and pest refuges. Calendar spraying and dense, wet canopies tend to increase rather than reduce risk.

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

Which statement best describes the purpose of a farm nutrient budget?

  1. It balances nutrient inputs against outputs to assess efficiency and losses Correct answer.
  2. It records the daily feed intake of each mob of stock
  3. It predicts the date of the first spring grazing
  4. It measures the pH of each paddock before fertiliser application

Explanation

A nutrient budget accounts for nutrients entering the farm (fertiliser, supplement, fixation) and leaving (products, leaching, volatilisation), allowing efficiency and loss to be assessed. This supports decisions on fertiliser and stocking.

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

Which practice best reduces soil erosion on a steep pastoral hillside?

  1. Cultivating the slope to establish new pasture
  2. Removing shelterbelts to increase airflow
  3. Grazing hard during wet winter months
  4. Maintaining a dense, well-rooted pasture cover Correct answer.

Explanation

A dense, well-rooted sward protects the soil surface from raindrop impact and holds soil particles in place, reducing erosion. Hard grazing and cultivation expose bare soil and increase loss.

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

Which feature of a plant variety is most associated with its genetic potential for yield?

  1. The method used to harvest it
  2. The colour of the flowers
  3. The genotype selected through breeding Correct answer.
  4. The time of day it is irrigated

Explanation

Yield potential is determined by the genetic makeup of a variety, which is the basis for breeding selection. Management factors such as irrigation and harvest influence how much of that potential is realised.

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

A grower wants to reduce the risk of nitrate leaching from a urine patch on a grazed paddock. Which approach is most effective?

  1. Increasing stocking rate in the same paddock
  2. Leaving the patch ungrazed for the rest of the year
  3. Applying more nitrogen fertiliser to dilute the patch
  4. Encouraging rapid pasture uptake and avoiding heavy late-autumn nitrogen applications Correct answer.

Explanation

Nitrate leaching risk is greatest when surplus nitrate is present and plant uptake is low, particularly in late autumn and winter. Matching nitrogen supply to pasture demand and avoiding late nitrogen applications reduces the surplus available to leach.

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

Which management strategy best reduces internal parasite burden in young lambs on pasture?

  1. Increasing lamb stocking density
  2. Grazing lambs repeatedly on the same paddock
  3. Treating only when lambs show severe clinical signs
  4. Using a planned drench programme with refugia and grazing management Correct answer.

Explanation

A planned programme that combines strategic drenching, maintaining a refugia population of unselected parasites, and grazing management slows resistance and reduces larval challenge. Waiting for severe signs allows contamination to build up.

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

Which explanation best accounts for the benefit of shelterbelts to horticultural crops on exposed sites?

  1. They reduce wind damage and evapotranspiration, improving growth Correct answer.
  2. They increase wind speed across the canopy
  3. They eliminate the need for irrigation
  4. They raise soil pH

Explanation

Shelter reduces wind speed, lowering mechanical damage and evaporative demand, which supports growth and fruit quality. Shelter does not remove the need for irrigation or alter soil pH.

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

A soil test shows Olsen P of 45 and a very low potassium level on a dairy farm. Which fertiliser strategy best addresses the potassium deficiency?

  1. Applying superphosphate only
  2. Applying a potassium fertiliser such as muriate of potash Correct answer.
  3. Applying nitrogen fertiliser
  4. Applying lime to raise pH

Explanation

Muriate of potash (potassium chloride) directly supplies potassium and is the standard choice for correcting a potassium deficiency. Superphosphate and nitrogen do not supply potassium, and lime addresses acidity.

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

In an integrated pest management programme, what is the main purpose of economic thresholds?

  1. To replace monitoring with calendar spraying
  2. To guide treatment timing based on pest density and crop value Correct answer.
  3. To determine the maximum pesticide dose allowed
  4. To eliminate all pests from the crop

Explanation

Economic thresholds define the pest density at which the cost of control equals the value of the damage prevented, guiding whether and when to treat. This avoids unnecessary sprays and supports IPM.

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

Which factor best explains why a legume component in a pasture mixture can improve animal performance?

  1. It raises the lignin content of the sward
  2. It reduces the protein content of the diet
  3. It lowers the fibre content of the diet and increases voluntary intake Correct answer.
  4. It increases the need for nitrogen fertiliser

Explanation

Legumes such as white clover are typically more digestible and lower in fibre than grasses, which increases voluntary intake and supports higher animal performance. They also fix nitrogen, reducing fertiliser need.

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

Which statement best describes the role of soil organic matter in maintaining soil structure?

  1. It binds soil particles into stable aggregates Correct answer.
  2. It eliminates the need for nutrients
  3. It reduces water-holding capacity
  4. It increases soil bulk density

Explanation

Organic matter acts as a binding agent, forming stable aggregates that improve porosity, aeration and water infiltration. It also increases water-holding capacity rather than reducing it.

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

In a breeding programme, why is selection based on estimated breeding values (EBVs) more effective than selection on raw phenotype alone?

  1. EBVs measure only the animal's current body weight
  2. EBVs ignore environmental effects entirely
  3. EBVs account for environmental influences and relatedness, improving prediction of genetic merit Correct answer.
  4. EBVs are based solely on the animal's age

Explanation

EBVs use pedigree and performance information to separate genetic merit from environmental effects, giving a more accurate prediction of the genes an animal passes on. Raw phenotype alone confounds genetics with management and environment.

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

Which practice best reduces the risk of soil structural damage from grazing wet pastures in winter?

  1. Standing stock off wet paddocks and using a feed pad or sacrifice paddock Correct answer.
  2. Grazing stock on wet paddocks at high stocking density
  3. Cultivating wet paddocks to improve drainage
  4. Increasing the number of stock on the wet paddock

Explanation

Standing stock off wet soils prevents pugging and compaction by keeping animal weight off the fragile surface. A feed pad or sacrifice paddock concentrates damage on a small area.

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

Which explanation best accounts for the benefit of crop rotation in a vegetable production system?

  1. It guarantees higher prices for the crop
  2. It removes the need for any pest monitoring
  3. It interrupts pest and disease cycles and helps maintain soil fertility Correct answer.
  4. It allows the same pest and disease cycle to continue

Explanation

Rotating to a different plant family interrupts the life cycles of soil-borne pathogens and pests and can improve nutrient balance. It does not guarantee prices or remove the need for monitoring.

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

A grower is considering using a cover crop between vegetable crops. Which reasoning best reflects the agronomic trade-off?

  1. Cover crops always increase the following crop's yield without cost
  2. Cover crops eliminate the need for fertiliser in all cases
  3. Cover crops have no effect on soil biology
  4. Cover crops can improve soil and suppress weeds but may use water and delay planting Correct answer.

Explanation

Cover crops can build organic matter, reduce erosion and suppress weeds, but they also use water and nutrients and can delay the following crop if termination is poorly timed. The decision requires weighing these benefits against costs.

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

Which statement best explains why irrigation scheduling based on soil moisture monitoring is preferred over fixed calendar scheduling?

  1. It guarantees no leaching will occur
  2. It removes the need to monitor crop stress
  3. It matches water supply to crop demand and reduces waste Correct answer.
  4. It applies water regardless of plant demand

Explanation

Monitoring soil moisture allows irrigation to be timed to actual crop water use, improving efficiency and reducing over-watering. Calendar scheduling ignores weather and soil variability and can waste water.

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

Which practice best reduces ammonia volatilisation losses when applying urea to pasture?

  1. Applying urea at very high rates in one pass
  2. Applying urea just before rain or irrigating it in Correct answer.
  3. Applying urea to dry, bare soil
  4. Applying urea on a hot, dry afternoon

Explanation

Volatilisation losses are greatest when urea sits on dry, warm surfaces without moisture to dissolve and incorporate it. Applying before rain or irrigation moves urea into the soil, reducing losses.

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

A dairy farm has high nitrogen inputs and low nitrogen use efficiency. Which change is most likely to improve efficiency?

  1. Reducing nitrogen inputs and improving pasture utilisation Correct answer.
  2. Applying nitrogen in late autumn
  3. Increasing imported supplement and fertiliser nitrogen
  4. Increasing stocking rate without changing feeding

Explanation

Low nitrogen use efficiency means much of the input is lost rather than converted to product. Reducing inputs and improving pasture utilisation (grazing management, matching supply to demand) captures more nitrogen in milk and reduces losses.

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

In a kiwifruit orchard, why might artificial pollination be used alongside bees?

  1. Bees damage the flowers
  2. Artificial pollination supplements bee activity when weather or bee numbers limit pollination Correct answer.
  3. Artificial pollination replaces the need for male vines
  4. Bees are ineffective at transferring pollen

Explanation

Bees are effective pollinators, but cool, wet or windy weather and low bee activity can limit pollination during the short flowering window. Artificial pollination supplements bee work to improve fruit set and fruit size.

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

Which statement best explains why a diverse pasture mix including plantain and chicory can reduce nitrogen leaching compared with ryegrass–clover alone?

  1. These species have deeper root systems and higher nitrogen uptake at times of leaching risk Correct answer.
  2. These species reduce pasture growth in summer
  3. These species fix more atmospheric nitrogen than clover
  4. These species increase urine patch concentration

Explanation

Deep-rooted species such as plantain and chicory can capture nitrate from deeper soil layers and grow actively when leaching risk is high, reducing the nitrate available to leach. They do not fix nitrogen like clover.

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

A grower applies the same fungicide active ingredient repeatedly against a foliar pathogen. Which outcome is most likely?

  1. The crop becomes immune to all diseases
  2. The fungicide becomes more effective over time
  3. Fungicide resistance develops in the pathogen population Correct answer.
  4. The pathogen population becomes more sensitive to the fungicide

Explanation

Repeated exposure to a single mode of action selects for resistant individuals within the pathogen population, reducing control. Resistance management uses different modes of action and integrates non-chemical controls.