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AFU Common Entrance Exam study materials
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AFU Common Entrance Exam practice questions

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Question 1Agriculture

Which soil texture class generally has the greatest water-holding capacity while still allowing adequate drainage for most field crops?

  1. Gravel
  2. Loam Correct answer.
  3. Sandy loam
  4. Coarse sand

Explanation

Loam contains a balanced mixture of sand, silt, and clay, giving it good aggregation, moderate pore space, and the ability to retain water while still draining freely. Coarse sands and gravels drain too rapidly and hold little water, while sandy loam holds less than a true loam. This balance is why loam is considered ideal for most field crops.

Question 2Agriculture

In crop rotation, including a legume such as cowpea mainly benefits the following cereal crop by:

  1. Adding fixed nitrogen to the soil Correct answer.
  2. Increasing soil bulk density
  3. Killing soil-borne fungi
  4. Raising soil pH

Explanation

Legumes form symbiotic associations with rhizobia that convert atmospheric nitrogen into forms plants can use, and residues release this nitrogen as they decompose. This reduces the nitrogen fertilizer needed by the following cereal. Legumes do not reliably raise pH or eliminate pathogens, and increasing bulk density would be harmful.

Question 3Agriculture

A farmer wants to control weeds in a maize field before the weeds emerge. Which herbicide timing is being described?

  1. Pre-emergence Correct answer.
  2. Fumigation
  3. Post-emergence
  4. Directed

Explanation

Pre-emergence herbicides are applied to the soil surface after sowing but before weeds (and often before the crop) emerge, forming a barrier that kills germinating weed seedlings. Post-emergence products are applied to already-emerged weeds, directed sprays target between crop rows, and fumigation sterilizes soil with gases.

Question 4Agriculture

Which of the following is the primary reason for applying lime to an acidic agricultural soil?

  1. To reduce organic matter
  2. To raise pH and improve nutrient availability Correct answer.
  3. To supply potassium
  4. To increase soil salinity

Explanation

Lime (calcium carbonate) neutralizes soil acidity, raising pH toward the range where most nutrients, especially phosphorus and molybdenum, become more available and where aluminium toxicity is reduced. It does not supply potassium, and raising salinity or destroying organic matter would be detrimental.

Question 5Agriculture

A herd of cattle is vaccinated against a viral disease. This practice is best described as:

  1. Euthanasia
  2. Therapy
  3. Quarantine
  4. Prophylaxis Correct answer.

Explanation

Vaccination is prophylactic because it prevents disease before exposure by stimulating protective immunity. Therapy treats existing illness, quarantine restricts movement of possibly infected animals, and euthanasia is humane killing. Prevention through vaccination is a cornerstone of herd health programs.

Question 6Agriculture

Which irrigation method typically delivers water most efficiently to the root zone of a widely spaced orchard?

  1. Furrow irrigation
  2. Drip irrigation Correct answer.
  3. Flood irrigation
  4. Sprinkler irrigation

Explanation

Drip irrigation applies water slowly and directly to the root zone through emitters, minimizing evaporation and runoff, which makes it highly efficient for widely spaced trees. Flood and furrow systems lose water to deep percolation and evaporation, and sprinklers wet foliage and non-root areas.

Question 7Agriculture

The main purpose of ploughing before planting is to:

  1. Increase soil compaction
  2. Sterilize the soil
  3. Loosen and invert the soil for seedbed preparation Correct answer.
  4. Raise the water table

Explanation

Ploughing breaks up compacted soil, buries residues and weeds, and creates a friable seedbed that lets roots penetrate and seeds germinate evenly. It does not sterilize soil, deliberately compact it, or affect the water table.

Question 8Agriculture

Which of the following is a cereal crop grown primarily for its grain?

  1. Sorghum Correct answer.
  2. Cassava
  3. Groundnut
  4. Soybean

Explanation

Sorghum is a grass grown mainly for its starchy grain used for food and feed. Soybean and groundnut are legumes grown for oil and protein, and cassava is a root crop grown for its starchy tubers.

Question 9Agriculture

A soil test reports a cation exchange capacity (CEC) of 25 cmol/kg. What does this value most directly indicate?

  1. A high capacity to retain exchangeable cations Correct answer.
  2. A high level of soluble salts
  3. A strongly acidic reaction
  4. A very sandy texture

Explanation

CEC measures the number of negatively charged sites on soil particles that hold cations such as calcium, magnesium, and potassium in exchangeable form. A value of 25 cmol/kg is relatively high, indicating strong nutrient retention, typically associated with clay or organic matter. It does not measure salinity, pH, or texture directly.

Question 10Agriculture

A field has a plant population of 50,000 plants per hectare and an average of 2.5 cobs per plant, each yielding 180 g of grain. What is the approximate grain yield?

  1. 11.25 t/ha
  2. 2.25 t/ha
  3. 45 t/ha
  4. 22.5 t/ha Correct answer.

Explanation

Yield equals plants per hectare multiplied by cobs per plant and by grain per cob: 50,000 × 2.5 × 0.180 kg = 22,500 kg, or 22.5 t/ha. Converting grams to kilograms before multiplying avoids a units error. This calculation assumes all cobs are harvested.

Question 11Agriculture

Which practice best reduces nitrate leaching from a field after harvest?

  1. Bare fallowing
  2. Establishing a cover crop Correct answer.
  3. Heavy irrigation
  4. Deep ploughing

Explanation

A cover crop takes up residual soil nitrate and holds it in plant tissue over winter, reducing leaching into groundwater. Bare fallow leaves nitrate vulnerable to leaching, deep ploughing can move nitrate downward, and heavy irrigation increases percolation losses.

Question 12Agriculture

A dairy cow shows reduced milk yield, weight loss, and a rough coat despite adequate feed. Which management action is most appropriate first?

  1. Withhold all water for a day
  2. Assess the ration for energy and protein balance and check for parasites Correct answer.
  3. Add more bedding to the stall
  4. Immediately increase milking frequency

Explanation

Reduced yield, weight loss, and poor coat condition suggest a nutritional deficiency or parasite burden, so evaluating the ration's energy and protein content and checking for internal parasites addresses the likely causes. Increasing milking frequency or withholding water would worsen the animal's condition, and bedding does not affect nutrition.

Question 13Agriculture

Integrated pest management (IPM) relies on which principle?

  1. Using only biological control agents
  2. Applying the maximum pesticide rate on a fixed calendar
  3. Combining monitoring, thresholds, and multiple control tactics Correct answer.
  4. Eliminating all insects from the field

Explanation

IPM integrates scouting, economic thresholds, cultural practices, biological control, and judicious pesticide use to keep pests below damaging levels. Calendar spraying ignores pest presence, eradication is unrealistic, and relying solely on biological agents is unnecessarily restrictive.

Question 14Agriculture

Which of the following best describes the function of rhizobia in the root nodules of a legume?

  1. Protecting roots from nematodes
  2. Absorbing phosphorus from the soil
  3. Breaking down soil organic matter
  4. Converting atmospheric nitrogen into ammonia for plant use Correct answer.

Explanation

Rhizobia live symbiotically in root nodules and use the enzyme nitrogenase to reduce atmospheric nitrogen to ammonia, which the plant assimilates. In return, the plant supplies carbohydrates. They do not decompose organic matter, absorb phosphorus, or defend against nematodes.

Question 15Agriculture

A seed lot has 90 percent germination and 95 percent purity. What is its pure live seed (PLS) percentage?

  1. 85.5 percent Correct answer.
  2. 95 percent
  3. 92.5 percent
  4. 90 percent

Explanation

Pure live seed is calculated by multiplying germination percentage by purity percentage: 0.90 × 0.95 = 0.855, or 85.5 percent. This figure tells growers how much of the seed lot will produce viable seedlings so seeding rates can be adjusted. Adding or averaging the two values is incorrect.

Question 16Agriculture

Which factor most strongly determines the length of the growing season for a rain-fed crop in a semi-arid region?

  1. Farm size
  2. Wind direction
  3. Soil colour
  4. Duration and amount of rainfall Correct answer.

Explanation

In semi-arid rain-fed systems, the period during which soil moisture is adequate for crop growth is governed mainly by the timing and amount of rainfall. Soil colour, wind direction, and farm size have little influence on the length of the moisture-limited growing period.

Question 17Agriculture

A farmer notices yellowing between the veins of older leaves in a maize crop. Which nutrient deficiency is most likely?

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

Explanation

Nitrogen is mobile in the plant, so deficiency symptoms such as chlorosis appear first on older leaves as nitrogen is redistributed to new growth. Iron, calcium, and boron are relatively immobile, so their deficiencies typically appear on young leaves first.

Question 18Agriculture

Which storage practice best reduces post-harvest losses of dry grain?

  1. Drying grain to safe moisture and storing in airtight containers Correct answer.
  2. Mixing grain with soil
  3. Storing grain in a warm, humid room
  4. Storing freshly harvested wet grain in open sacks

Explanation

Drying grain to a safe moisture level before storage prevents mould growth and insect proliferation, and airtight containers limit oxygen and moisture exchange. Wet grain in open sacks, soil contamination, and warm humid conditions all accelerate spoilage and pest damage.

Question 19Agriculture

Cross-pollination in maize is mainly achieved by:

  1. Butterflies
  2. Honeybees
  3. Birds
  4. Wind Correct answer.

Explanation

Maize is a wind-pollinated crop; its tassels shed large quantities of light pollen that are carried by air currents to silks on neighbouring plants. Insects and birds play negligible roles in maize pollination. This is why isolation distances matter in seed production.

Question 20Agriculture

A farmer applies 200 kg of a 20-10-10 fertilizer per hectare. How much nitrogen (N) is applied?

  1. 60 kg N/ha
  2. 40 kg N/ha Correct answer.
  3. 20 kg N/ha
  4. 200 kg N/ha

Explanation

The first number in a fertilizer grade is the percentage of nitrogen by mass, so 20 percent of 200 kg is 40 kg of N per hectare. The remaining nutrients are 20 kg of P2O5 and 20 kg of K2O. Multiplying by the wrong grade number gives incorrect answers.

Question 21Agriculture

Which of the following is an example of a cultural method of weed control?

  1. Releasing a herbivorous insect
  2. Burning with a flame weeder
  3. Applying glyphosate
  4. Mulching and crop rotation Correct answer.

Explanation

Cultural weed control uses management practices such as mulching, crop rotation, and competitive crop canopies to suppress weeds. Herbicides are chemical, insects are biological, and flame weeders are physical or mechanical methods.

Question 22Agriculture

A poultry producer observes a sudden drop in egg production with soft-shelled eggs. Which nutritional factor should be examined first?

  1. Protein content of the starter feed
  2. Litter depth
  3. Calcium and phosphorus balance in the layer ration Correct answer.
  4. Water temperature

Explanation

Soft-shelled eggs indicate a shortage or imbalance of calcium and available phosphorus, which are needed for shell formation. Layer diets must supply adequate calcium, usually as limestone, and a correct calcium-to-phosphorus ratio. Starter feed protein, water temperature, and litter depth do not directly explain shell quality.

Question 23Agriculture

In a breeding program, a farmer repeatedly selects plants with the highest grain yield over several generations. This is an example of:

  1. Mass selection Correct answer.
  2. Hybridization
  3. Mutation breeding
  4. Tissue culture

Explanation

Mass selection involves choosing superior individual plants based on phenotype and propagating their seed to build a improved population. Mutation breeding uses induced genetic change, hybridization crosses distinct parents, and tissue culture propagates plants vegetatively.

Question 24Agriculture

A farmer wants to reduce soil erosion on a steep slope. Which combination of practices is most appropriate?

  1. Ploughing up and down the slope
  2. Removing all vegetation
  3. Deep ripping along the slope
  4. Contour ploughing combined with vegetative strips Correct answer.

Explanation

Contour ploughing follows the slope's elevation lines, slowing runoff, and vegetative strips trap sediment and stabilize soil. Ploughing up and down the slope channels water and accelerates erosion, bare soil is highly erodible, and ripping along the slope can concentrate flow.

Question 25Agriculture

Which statement about the economic threshold in pest management is correct?

  1. It is the maximum pesticide dose allowed by law
  2. It is the pest density at which control measures should be initiated to prevent economic loss Correct answer.
  3. It is the level of pest damage that has already caused crop failure
  4. It is the total number of pests a field can support

Explanation

The economic threshold is the pest population level at which the cost of control equals the value of the damage that would occur if no action were taken, so intervention becomes justified. It is not a legal dose limit, a carrying capacity, or a level of already-total loss.

Question 26Agriculture

Which soil structure type is most favourable for root penetration and water movement in a cultivated topsoil?

  1. Columnar structure
  2. Granular (crumb) structure Correct answer.
  3. Platy structure
  4. Massive structure

Explanation

Granular or crumb structure consists of small, rounded aggregates with many pore spaces between them, which allows roots to penetrate easily and permits rapid water infiltration and drainage. Platy, columnar and massive structures restrict both air and water movement because they lack well-formed, rounded aggregates.

Question 27Agriculture

Which process converts ammonium (NH4+) to nitrate (NO3-) in the soil?

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

Explanation

Nitrification is the two-step microbial oxidation of ammonium to nitrite and then to nitrate, carried out mainly by Nitrosomonas and Nitrobacter. It makes nitrogen available as nitrate, which is highly mobile and readily taken up by crops.

Question 28Agriculture

Which livestock species is a ruminant with a four-compartment stomach?

  1. Sheep Correct answer.
  2. Horse
  3. Chicken
  4. Pig

Explanation

Sheep are true ruminants with a four-compartment stomach (rumen, reticulum, omasum, abomasum) in which microbial fermentation of fibrous feed occurs. Pigs and poultry are monogastric, and the horse is a hindgut fermenter rather than a ruminant.

Question 29Agriculture

Which term describes the removal of excess surface water from farmland by open channels or buried pipes?

  1. Drainage Correct answer.
  2. Leaching
  3. Irrigation
  4. Mulching

Explanation

Drainage is the removal of surplus water from the soil profile through open ditches, mole drains or buried tile pipes, preventing waterlogging and improving aeration. Irrigation, by contrast, adds water to the field.

Question 30Agriculture

Which pest control agent is derived from the bacterium Bacillus thuringiensis and acts as a stomach poison in caterpillars?

  1. A soil fumigant
  2. A microbial insecticide Correct answer.
  3. A contact herbicide
  4. A synthetic pyrethroid

Explanation

Bacillus thuringiensis produces protein crystals that are toxic to the larvae of many Lepidoptera when ingested, making it a biological or microbial insecticide. It is not a synthetic chemical, a fumigant or a herbicide.

Question 31Agriculture

Which animal product is the primary output of a broiler enterprise?

  1. Meat Correct answer.
  2. Eggs
  3. Wool
  4. Milk

Explanation

Broiler production is specialised for rapid growth of young chickens to supply poultry meat. Egg production comes from layers, while milk and wool come from dairy cattle and sheep respectively.

Question 32Agriculture

Which practice is the standard method for conserving soil moisture in a dryland field between cropping seasons?

  1. Maintaining a surface mulch or stubble cover Correct answer.
  2. Flood irrigation during the dry period
  3. Removing all crop residues after harvest
  4. Deep ploughing to bring subsoil to the surface

Explanation

A mulch or stubble cover reduces evaporation from the soil surface, lowers surface temperature and protects against erosion, thereby conserving stored moisture. Removing residues or deep ploughing exposes moist soil and increases evaporative losses.

Question 33Agriculture

Which unit is used to express the concentration of a nutrient element in a soil test report?

  1. Kilograms per hectare (kg/ha)
  2. Litres per second (L/s)
  3. Milligrams per kilogram (mg/kg) Correct answer.
  4. Megapascals (MPa)

Explanation

Soil test results for available nutrients are reported as a concentration in the soil, commonly milligrams per kilogram (ppm) or cmol/kg. Application rates are expressed in kg/ha, but the soil test itself measures concentration.

Question 34Agriculture

A farmer applies 300 kg of urea (46% N) per hectare. How much nitrogen is applied?

  1. 46 kg N/ha
  2. 64 kg N/ha
  3. 300 kg N/ha
  4. 138 kg N/ha Correct answer.

Explanation

Nitrogen applied equals the product mass multiplied by the nitrogen percentage: 300 kg × 0.46 = 138 kg N/ha. The remaining mass is mainly carbon, oxygen, hydrogen and the carrier fraction.

Question 35Agriculture

A crop requires 120 kg N/ha. How much ammonium sulphate (21% N) must be applied per hectare?

  1. 252 kg/ha
  2. 571 kg/ha Correct answer.
  3. 2520 kg/ha
  4. 120 kg/ha

Explanation

Divide the required nitrogen by the nutrient concentration: 120 ÷ 0.21 = 571 kg of ammonium sulphate per hectare. This delivers the 120 kg N needed by the crop.

Question 36Agriculture

Which factor most directly determines the plant-available water-holding capacity of a soil?

  1. Slope aspect
  2. Texture and organic matter content Correct answer.
  3. Soil colour
  4. Presence of earthworms alone

Explanation

Textural class and organic matter content determine pore-size distribution, which governs how much water a soil can hold and release to plants. Sandy soils hold little water, while clay and organic-rich soils hold more.

Question 37Agriculture

A field has a plant population of 40,000 plants per hectare and each plant produces an average of 150 g of grain. What is the estimated grain yield?

  1. 6,000 kg/ha Correct answer.
  2. 600 kg/ha
  3. 1,500 kg/ha
  4. 60,000 kg/ha

Explanation

Yield equals plants per hectare multiplied by grain per plant: 40,000 × 0.150 kg = 6,000 kg/ha, or 6 tonnes per hectare. Converting grams to kilograms before multiplying avoids errors of scale.

Question 38Agriculture

Which practice is the most effective way to break the life cycle of a soil-borne pathogen that survives in crop residues?

  1. Increasing plant density
  2. Irrigating more frequently
  3. Rotating with a non-host crop for several seasons Correct answer.
  4. Applying a nitrogen top-dressing

Explanation

A non-host rotation deprives the pathogen of its host and allows residue to decompose, reducing inoculum in the soil. Fertilizer, density and irrigation changes do not remove the pathogen's food source.

Question 39Agriculture

Which livestock feeding practice best reduces the risk of acidosis in cattle fed a high-grain diet?

  1. Gradual adaptation with adequate roughage in the ration Correct answer.
  2. Removal of all forage from the diet
  3. Sudden introduction of the full grain ration
  4. Feeding large single meals once daily

Explanation

Rumen microbes need time to adapt to starch, and roughage stimulates chewing and saliva production, which buffers rumen pH. Sudden grain loading or forage removal allows acid accumulation and causes acidosis.

Question 40Agriculture

Which management measure is most appropriate for controlling mastitis in a dairy herd?

  1. Feeding hay only during lactation
  2. Increasing the protein content of the concentrate
  3. Post-milking teat disinfection and regular milking-machine maintenance Correct answer.
  4. Extending the milking interval

Explanation

Mastitis is largely an infectious disease of the udder, so teat disinfection after milking and properly maintained machines reduce bacterial entry and teat damage. Nutritional or milking-interval changes do not address the infection route.

Question 41Agriculture

Which characteristic best distinguishes a hybrid maize variety from an open-pollinated variety?

  1. Hybrid seed must be repurchased each season to maintain performance Correct answer.
  2. Open-pollinated varieties always outyield hybrids
  3. Hybrids are propagated only by vegetative cuttings
  4. Hybrid seed can be saved indefinitely without yield loss

Explanation

Hybrid performance depends on the specific combination of parent lines, so grain saved from a hybrid segregates and loses vigour in the next generation. Open-pollinated varieties can be saved and reselected, though they generally yield less than hybrids.

Question 42Agriculture

Which soil conservation measure is most suitable for a field with a gentle slope of 3 to 5 percent?

  1. Planting in straight up-and-down rows
  2. Contour cultivation with grassed waterways Correct answer.
  3. Complete levelling of the field
  4. Terracing with concrete walls

Explanation

On gentle slopes, contour cultivation slows runoff and grassed waterways safely carry concentrated flow, giving effective erosion control at low cost. Concrete terracing is excessive for such gradients, and up-and-down rows accelerate erosion.

Question 43Agriculture

A farmer wants to determine the germination capacity of a seed lot before planting. Which test is appropriate?

  1. A moisture meter reading of the grain store
  2. A standard germination test on replicate samples in controlled conditions Correct answer.
  3. A visual inspection of the seed bag
  4. A soil test of the field

Explanation

A standard germination test sows replicate samples under controlled moisture and temperature and counts normal seedlings, giving a reliable percentage. Visual inspection, soil tests and store moisture readings do not measure seed viability.

Question 44Agriculture

Which practice most effectively reduces ammonia loss when urea is broadcast on the soil surface?

  1. Mixing urea with lime before spreading
  2. Leaving urea on the surface without rain
  3. Incorporating the urea into the soil soon after application Correct answer.
  4. Applying urea on a hot, windy afternoon

Explanation

Urea hydrolyses to ammonium at the surface, and warm, dry, windy conditions favour ammonia volatilisation. Incorporating urea into the soil places the ammonium where it is adsorbed and protected from loss.

Question 45Agriculture

Which factor is most important when selecting a site for a fish pond in a smallholder aquaculture system?

  1. A sandy subsoil for rapid seepage
  2. Proximity to a busy road for marketing
  3. A reliable water supply and suitable clay soil that holds water Correct answer.
  4. A steep rocky slope for easy drainage

Explanation

A pond needs a dependable water source and a soil with sufficient clay to seal the bottom and hold water. Steep rocky or sandy sites lose water and are difficult to construct and manage.

Question 46Agriculture

Which statement best explains why legumes are included in a crop rotation with cereals?

  1. Legumes remove all nitrogen from the soil
  2. Legumes add nitrogen to the soil through symbiotic fixation Correct answer.
  3. Legumes prevent all weed growth
  4. Legumes eliminate the need for any fertilizer

Explanation

Rhizobia in legume root nodules fix atmospheric nitrogen, and the residues release it for the following cereal crop. This reduces the nitrogen fertilizer requirement and breaks cereal disease cycles.

Question 47Agriculture

Which measure is most appropriate for controlling a stored-grain insect infestation without chemical fumigation?

  1. Increasing the moisture content of the grain
  2. Mixing grain with moist sand
  3. Hermetic storage that excludes oxygen Correct answer.
  4. Storing grain in open bags in sunlight

Explanation

Hermetic storage seals grain in an airtight container so that insects consume the available oxygen and die, giving chemical-free control. Raising moisture or leaving bags open encourages further infestation and mould.

Question 48Agriculture

A soil analysis reports a pH of 4.8 for a field intended for maize. Which action is most appropriate?

  1. Apply gypsum to raise the pH
  2. Apply agricultural lime and incorporate it before planting Correct answer.
  3. Apply elemental sulphur to lower the pH further
  4. Do nothing, since maize prefers strongly acid soils

Explanation

A pH of 4.8 is strongly acid and reduces the availability of phosphorus and molybdenum while increasing aluminium toxicity. Lime raises pH toward the target range for maize, and incorporation helps it react throughout the topsoil.

Question 49Agriculture

A farmer has a 2-hectare field and needs to apply a herbicide at 1.5 kg of active ingredient per hectare from a formulation containing 50% active ingredient. How much formulated product is required in total?

  1. 3 kg
  2. 12 kg
  3. 1.5 kg
  4. 6 kg Correct answer.

Explanation

Active ingredient needed is 1.5 kg/ha × 2 ha = 3 kg. Since the product is 50% active ingredient, formulated product is 3 ÷ 0.5 = 6 kg for the whole field.

Question 50Agriculture

Which statement about the water table and capillary rise best explains salt accumulation at the soil surface in an irrigated arid region?

  1. Salts are removed from the surface by capillary rise
  2. Surface salt accumulation occurs only in humid climates
  3. Deep water tables always cause surface salinisation
  4. A shallow saline water table allows capillary rise and evaporation to deposit salts at the surface Correct answer.

Explanation

When the water table is shallow, capillary action draws saline water upward and evaporation leaves the dissolved salts behind at or near the surface. Keeping the water table deep and applying leaching water prevents this salinisation.