I85PREP
⌘ K
IBPS AFO study materials
IBPS AFO study resources

IBPS AFO practice questions

One question at a time. Build your IBPS AFO 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 1Agriculture (professional knowledge for Agricultural Field Officer)

Which soil order in USDA Soil Taxonomy is characterised by a thick, dark surface horizon rich in organic matter and high base saturation, typical of the North American prairies and the Deccan black cotton soils of India?

  1. Oxisol
  2. Histosol
  3. Spodosol
  4. Mollisol Correct answer.

Explanation

Mollisols are defined by a mollic epipedon: a thick, dark, base-saturated surface horizon formed under grassland vegetation. The Indian black cotton soils (vertisols in Soil Taxonomy) often qualify as Mollisols because of their dark, high-base-saturation surface horizon. The other orders lack this combination of dark colour, structure and base saturation.

Question 2Agriculture (professional knowledge for Agricultural Field Officer)

In the classification of Indian soils, which soil group covers the largest area of the country and is derived largely from alluvium deposited by the Indo-Gangetic river systems?

  1. Laterite soil
  2. Alluvial soil Correct answer.
  3. Red soil
  4. Black soil

Explanation

Alluvial soils occupy roughly one-fourth of India's geographical area, the largest single group, and are formed from sediments transported and deposited by the Himalayan and peninsular rivers. They are widespread in the Indo-Gangetic plains, coastal deltas and river valleys. Black, red and laterite soils occupy smaller shares.

Question 3Agriculture (professional knowledge for Agricultural Field Officer)

A soil sample has a pH of 5.2 and the field is to be planted with a acid-sensitive pulse crop. Which amendment is agronomically appropriate to raise the pH towards the target range?

  1. Gypsum (calcium sulphate)
  2. Agricultural lime (calcium carbonate) Correct answer.
  3. Elemental sulphur
  4. Aluminium sulphate

Explanation

Acidic soils are corrected by adding a base-forming material, and ground limestone (calcium carbonate) is the standard amendment because it neutralises exchangeable aluminium and hydrogen and raises pH. The quantity required is fixed from the lime requirement test and the buffer capacity of the soil. Gypsum and aluminium sulphate supply calcium but do not raise pH.

Question 4Agriculture (professional knowledge for Agricultural Field Officer)

Which essential plant nutrient is absorbed mainly as the divalent cation and is a central atom of the chlorophyll molecule?

  1. Magnesium Correct answer.
  2. Molybdenum
  3. Iron
  4. Manganese

Explanation

Magnesium is taken up as Mg2+ and occupies the centre of the porphyrin ring of every chlorophyll molecule, so deficiency produces interveinal chlorosis on older leaves first. It also acts as a cofactor for many enzymes including ATPases and kinases. Iron and manganese are also involved in chloroplast function but are not constituents of chlorophyll.

Question 5Agriculture (professional knowledge for Agricultural Field Officer)

Which group of organisms is chiefly responsible for converting ammonium to nitrate in aerobic agricultural soils?

  1. Free-living nitrogen fixers such as Azotobacter
  2. Mycorrhizal fungi
  3. Denitrifying bacteria such as Pseudomonas
  4. Nitrifying bacteria such as Nitrosomonas and Nitrobacter Correct answer.

Explanation

Nitrification is a two-step aerobic process: Nitrosomonas-type bacteria oxidise ammonium to nitrite and Nitrobacter-type bacteria oxidise nitrite to nitrate. The process is favoured by warm, moist, well-aerated, neutral to slightly alkaline soils. The other groups either fix nitrogen, reduce nitrate, or form symbioses with roots.

Question 6Agriculture (professional knowledge for Agricultural Field Officer)

Seed rate for a crop is calculated with the formula (target plant population × test weight) ÷ (germination % × purity % × 100). If the target population is 400,000 plants per hectare and test weight is 40 g, what is the seed rate when germination is 90 percent and purity 100 percent?

  1. 16 kg/ha
  2. 17.8 kg/ha Correct answer.
  3. 20 kg/ha
  4. 14.4 kg/ha

Explanation

Using the formula, 400,000 × 40 g gives 16,000,000 g or 160 kg of pure germinable seed equivalent. Dividing by 90 percent germination (0.90) gives 177.8 kg per 10, which is 17.8 kg/ha. Purity of 100 percent does not change the result.

Question 7Agriculture (professional knowledge for Agricultural Field Officer)

Which irrigation scheduling approach bases the next irrigation on the cumulative evaporation from a standard pan multiplied by a crop coefficient?

  1. Tensiometer method
  2. Feel-and-appearance method
  3. IW/CPE ratio method Correct answer.
  4. Gravimetric sampling method

Explanation

The irrigation water to cumulative pan evaporation (IW/CPE) ratio schedules irrigation when a fixed depth of water has been depleted relative to pan evaporation, adjusted by a crop coefficient. A common ratio for many field crops is 0.8 to 1.0. The other methods measure soil moisture directly rather than using evaporative demand.

Question 8Agriculture (professional knowledge for Agricultural Field Officer)

In apiculture, which caste of honeybee performs the dance that communicates the direction and distance of a food source to foragers?

  1. Worker field bee Correct answer.
  2. Queen
  3. Forager nurse bee
  4. Drone

Explanation

The round and waggle dances are performed by worker field bees that have located nectar or pollen and return to the hive. The angle of the waggle run relative to vertical encodes direction relative to the sun, and the duration encodes distance. Drones and the queen do not forage.

Question 9Agriculture (professional knowledge for Agricultural Field Officer)

A farmer wants to control a lepidopteran pod borer using a microbial biopesticide that acts as a stomach poison. Which product matches this mode of action?

  1. Bacillus thuringiensis var. kurstaki Correct answer.
  2. Beauveria bassiana
  3. Pseudomonas fluorescens
  4. Trichoderma viride

Explanation

Bacillus thuringiensis produces crystalline delta-endotoxins that are activated in the alkaline larval gut and destroy gut epithelial cells, so it must be ingested. It is therefore effective against lepidopteran larvae such as pod borers. The other organisms are mainly antagonists or contact pathogens.

Question 10Agriculture (professional knowledge for Agricultural Field Officer)

Which breeding method involves growing the F1 generation and selecting individual plants in subsequent generations without deliberate selfing or crossing, relying on natural pollination?

  1. Bulk method Correct answer.
  2. Backcross method
  3. Pedigree method
  4. Mutation breeding

Explanation

In the bulk method the F2 and later generations are grown as a bulk population and natural selection operates until single plants are selected, usually from F5 or F6 onwards. It is cheap and suited to handling large populations, though it gives less control over individual genotypes than pedigree selection.

Question 11Agriculture (professional knowledge for Agricultural Field Officer)

A cytoplasmic-genetic male sterility system is used to produce hybrid seed in a crop. Which component must be grown in isolation and is essential for the hybrid seed to be fertile?

  1. The maintainer line grown without isolation
  2. The B line with normal cytoplasm
  3. The R line with restorer genes Correct answer.
  4. The A line carrying sterile cytoplasm

Explanation

In a three-line hybrid system the A line is male sterile, the B line maintains sterility, and the R line supplies dominant restorer genes so that the F1 hybrid is male fertile. The R line must be grown in isolation and its pollen used to pollinate the A line. Without restoration the hybrid would remain sterile.

Question 12Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is a characteristic symptom of bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae?

  1. Orange-yellow powdery pustules on the leaf surface
  2. Silver-grey streaks with black dots on the panicle neck
  3. Water-soaked lesions that turn yellow to white along leaf margins, starting from the tip Correct answer.
  4. Circular brown spots with grey centres scattered on the leaf blade

Explanation

Bacterial blight produces water-soaked stripes along the leaf margins that enlarge and become yellow to straw-white, often beginning near the leaf tip, and bacterial ooze may appear in humid conditions. The disease spreads through irrigation water, rain splash and infected seed. The other descriptions match fungal diseases.

Question 13Agriculture (professional knowledge for Agricultural Field Officer)

A cotton field shows upward curling of leaves, thickened veins and enations on the underside of leaves, with stunted plants. Which pest is the most likely vector of the causal agent?

  1. Cotton aphid
  2. American bollworm
  3. Whitefly Correct answer.
  4. Pink bollworm

Explanation

The symptoms describe cotton leaf curl disease, a begomovirus transmitted persistently and circulatively by the whitefly Bemisia tabaci. Whitefly management is therefore central to controlling the disease. The other insects are chewing or sap-sucking pests that do not transmit this virus.

Question 14Agriculture (professional knowledge for Agricultural Field Officer)

Which herbicide is a selective, systemic, post-emergence graminicide that inhibits acetyl-CoA carboxylase and is used to control grassy weeds in broadleaf crops?

  1. Quizalofop-p-ethyl Correct answer.
  2. Pendimethalin
  3. Paraquat
  4. Atrazine

Explanation

Quizalofop-p-ethyl belongs to the aryloxyphenoxypropionate group and inhibits acetyl-CoA carboxylase in grasses, giving selective post-emergence control of grassy weeds in broadleaf crops such as soybean and groundnut. Atrazine and pendimethalin act mainly through soil application, and paraquat is a non-selective contact herbicide.

Question 15Agriculture (professional knowledge for Agricultural Field Officer)

In a crop rotation, a cereal is followed by a grain legume. Which benefit is most directly attributable to the legume component?

  1. Reduced leaching of nitrate below the root zone
  2. Increased soil organic carbon from cereal residues
  3. Symbiotic nitrogen fixation adding nitrogen to the system Correct answer.
  4. Improved soil structure through deep tap roots

Explanation

Grain legumes form nodules with rhizobia and fix atmospheric nitrogen, part of which remains in the soil and stubble for the following crop. This is the classic rotational benefit of including a pulse in a cereal sequence. The other effects are real but are not specific to the legume's nitrogen contribution.

Question 16Agriculture (professional knowledge for Agricultural Field Officer)

Which package of practices is recommended for safe storage of wheat grain at farm level to prevent insect infestation?

  1. Store at 18 to 20 percent moisture in open bags
  2. Store freshly harvested grain directly in jute bags without drying
  3. Dry grain to about 12 percent moisture and store in airtight or fumigated structures Correct answer.
  4. Mix grain with water before sealing in metal bins

Explanation

Wheat should be dried to roughly 12 percent moisture before storage, and the structure should be clean and either airtight or treated with a approved fumigant such as aluminium phosphide under supervision. Low moisture and exclusion of oxygen suppress insect multiplication and mould growth. High-moisture storage leads to heating, caking and mycotoxin risk.

Question 17Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the correct sequence of operations in the cultivation of transplanted rice?

  1. Puddling, nursery sowing, harvesting, transplanting
  2. Nursery sowing, puddling, transplanting, main-field manuring, harvesting
  3. Nursery sowing, puddling and levelling, transplanting of seedlings, weeding and fertiliser application, harvesting Correct answer.
  4. Direct seeding, puddling, transplanting, threshing

Explanation

Transplanted rice begins with raising seedlings in a nursery, followed by puddling and levelling of the main field to create a soft reduced-soil root bed, then transplanting of 20 to 25 day old seedlings, and finally crop care including weeding, fertiliser top dressing and harvesting. Puddling before nursery sowing or harvesting before transplanting is impossible in the normal sequence.

Question 18Agriculture (professional knowledge for Agricultural Field Officer)

The normal lapse rate of temperature in the troposphere is approximately 6.5 degrees Celsius per kilometre of ascent. If the temperature at ground level is 30 degrees Celsius, what is the approximate temperature at 2 km altitude?

  1. 23 degrees Celsius
  2. 13 degrees Celsius
  3. 17 degrees Celsius Correct answer.
  4. 20 degrees Celsius

Explanation

Applying the lapse rate, 2 km of ascent reduces temperature by 2 × 6.5 = 13 degrees Celsius. Subtracting 13 from 30 gives 17 degrees Celsius. This environmental lapse rate is used in agro-meteorology for estimating temperature at different elevations and for frost risk assessment.

Question 19Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following describes the role of a 'maintainer line' in hybrid seed production using cytoplasmic-genetic male sterility?

  1. It is male sterile and serves as the female parent
  2. It is a synthetic variety used for open pollination
  3. It restores fertility in the F1 hybrid
  4. It has normal fertile cytoplasm and is used to pollinate the A line to produce more A-line seed Correct answer.

Explanation

The maintainer (B) line carries normal fertile cytoplasm and the same nuclear background as the A line but lacks restorer genes. When it pollinates the male-sterile A line, the progeny remain male sterile, allowing the A line to be multiplied. Restorer lines, by contrast, make the F1 fertile.

Question 20Agriculture (professional knowledge for Agricultural Field Officer)

A field soil test reports 280 kg/ha of available nitrogen, and the recommended dose for the crop is 120 kg N/ha. If the soil contribution is credited at 30 percent of available nitrogen, what quantity of fertiliser nitrogen should be applied?

  1. 84 kg N/ha
  2. 120 kg N/ha
  3. 36 kg N/ha Correct answer.
  4. 48 kg N/ha

Explanation

Thirty percent of 280 kg/ha is 84 kg/ha as the soil nitrogen credit. Subtracting this credit from the 120 kg/ha recommendation leaves 36 kg N/ha to be supplied through fertiliser. Crediting soil nutrients reduces unnecessary fertiliser use and cost.

Question 21Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is a key advantage of drip irrigation over surface flooding in a horticultural crop?

  1. It requires no filtration or maintenance
  2. It uniformly wets the entire soil surface
  3. It leaches salts away from the root zone more effectively than flooding
  4. It applies water directly to the root zone with high application efficiency and reduced weed growth between rows Correct answer.

Explanation

Drip irrigation delivers water slowly and directly to the root zone, achieving application efficiencies of 85 to 95 percent and keeping the inter-row area dry, which suppresses weeds and reduces evaporation. It also permits fertigation. It does not wet the whole surface and needs filtration to prevent emitter clogging.

Question 22Agriculture (professional knowledge for Agricultural Field Officer)

Which agricultural extension approach is characterised by transferring technologies developed at research stations to farmers through demonstrations and field days, with the farmer treated mainly as a recipient?

  1. Farmer field school
  2. Participatory rural appraisal
  3. Technology transfer model Correct answer.
  4. Participatory technology development

Explanation

The technology transfer model is a linear, top-down approach in which research generates innovations and extension delivers them to farmers through demonstrations, field days and mass media. It contrasts with participatory approaches that involve farmers in diagnosis and technology design. Recognising the model helps explain why adoption can be low when technologies are not locally adapted.

Question 23Agriculture (professional knowledge for Agricultural Field Officer)

A soil has an exchangeable sodium percentage of 18 and a pH of 9.4 with poor infiltration. Which reclamation strategy is most appropriate?

  1. Apply gypsum and leach with good-quality water while providing subsurface drainage Correct answer.
  2. Flood the field without drainage to dilute the sodium
  3. Apply lime to raise pH further
  4. Apply ammonium sulphate to increase acidity

Explanation

These values indicate a sodic soil, where excess exchangeable sodium disperses clay and destroys structure. Gypsum supplies calcium that replaces sodium on the exchange complex, and the displaced sodium must then be leached below the root zone with adequate drainage. Without drainage, leaching would raise the water table and worsen the problem.

Question 24Agriculture (professional knowledge for Agricultural Field Officer)

In a quantitative genetics experiment, the phenotypic variance of a trait is 400 and the environmental variance is 100. What is the broad-sense heritability of the trait?

  1. 0.90
  2. 0.75 Correct answer.
  3. 0.50
  4. 0.25

Explanation

Broad-sense heritability is the ratio of genetic variance to phenotypic variance. Genetic variance equals 400 minus 100, which is 300, so heritability is 300/400 = 0.75. A value of this magnitude indicates that selection for the trait in the given environment should be reasonably effective.

Question 25Agriculture (professional knowledge for Agricultural Field Officer)

A crop has a crop coefficient of 1.15 at mid-season and the reference evapotranspiration for the period is 6 mm per day. If the soil water balance shows no stress and effective rainfall is negligible, what is the approximate daily crop water use?

  1. 5.2 mm
  2. 6.9 mm Correct answer.
  3. 7.5 mm
  4. 4.8 mm

Explanation

Crop evapotranspiration is estimated as ETc = Kc × ETo, so 1.15 × 6 mm gives 6.9 mm per day. This value is used to schedule irrigation by comparing cumulative crop water use with the available soil moisture in the root zone. The crop coefficient varies with growth stage and is highest at mid-season.

Question 26Agriculture (professional knowledge for Agricultural Field Officer)

Which soil order is characterized by a thick, dark surface horizon rich in organic matter and high base saturation, typically formed under grassland vegetation?

  1. Ultisol
  2. Spodosol
  3. Mollisol Correct answer.
  4. Oxisol

Explanation

Mollisols are the grassland soils with a dark, organic-rich epipedon (mollic horizon) and high base saturation, making them among the most fertile soils. They form under prairie or steppe vegetation where deep root systems and low leaching build humus. Oxisols, Spodosols, and Ultisols are strongly weathered or leached and do not have this combination of properties.

Question 27Agriculture (professional knowledge for Agricultural Field Officer)

In the context of plant nutrient deficiency, which symptom is most characteristic of magnesium deficiency in a crop?

  1. Marginal necrosis on young leaves
  2. Interveinal chlorosis on older leaves Correct answer.
  3. Purple coloration on older leaves
  4. Stunted growth with dark green leaves

Explanation

Magnesium is a central component of chlorophyll and is mobile in the phloem, so deficiency appears first as interveinal chlorosis on older leaves. The plant remobilizes Mg from older to younger tissue, leaving the older leaves yellow between green veins. Purple coloration suggests phosphorus deficiency, dark green stunting suggests nitrogen deficiency, and marginal necrosis on young leaves suggests calcium or boron deficiency.

Question 28Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the primary purpose of treating legume seed with a Rhizobium culture before sowing?

  1. To protect seedlings from soil-borne fungal pathogens
  2. To increase nodulation and symbiotic nitrogen fixation Correct answer.
  3. To accelerate germination by breaking seed dormancy
  4. To supply starter nitrogen to the young seedling

Explanation

Rhizobium inoculant introduces compatible rhizobia that form root nodules and fix atmospheric nitrogen in symbiosis with the legume. This improves the nitrogen supply to the crop and often leaves residual nitrogen for the following crop. It is not a fungicide, a dormancy-breaking treatment, or a nitrogen fertilizer.

Question 29Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is a kharif season crop in the Indian cropping calendar?

  1. Pearl millet (bajra) Correct answer.
  2. Chickpea (gram)
  3. Wheat
  4. Mustard

Explanation

Pearl millet is sown with the onset of the south-west monsoon and harvested in autumn, making it a kharif crop. Wheat, mustard, and chickpea are rabi crops grown in the cool, dry winter season. The distinction depends on the season of sowing and the crop's temperature and moisture requirements.

Question 30Agriculture (professional knowledge for Agricultural Field Officer)

Which type of tillage is performed to loosen soil below the normal ploughing depth without inverting the soil, in order to break a compacted layer?

  1. Disc ploughing
  2. Rotavating
  3. Levelling
  4. Subsoiling Correct answer.

Explanation

Subsoiling uses a heavy tine or subsoiler to fracture compacted subsoil layers below the depth reached by ordinary ploughs, improving water infiltration and root penetration. It does not invert the soil profile. Disc ploughing and rotavating work the surface layer, and levelling is a land-shaping operation.

Question 31Agriculture (professional knowledge for Agricultural Field Officer)

In apiculture, which product is primarily harvested from the brood combs and used as a protein-rich feed supplement?

  1. Bee pollen Correct answer.
  2. Propolis
  3. Honey
  4. Beeswax

Explanation

Pollen is collected by foragers and stored in comb cells as bee bread; it is the colony's main protein source and can be harvested with pollen traps for use as a feed supplement. Honey is the carbohydrate store, beeswax is comb-building material, and propolis is a resinous sealant. Pollen is the protein-rich product associated with brood rearing.

Question 32Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the correct botanical name of the causal organism of late blight of potato?

  1. Rhizoctonia solani
  2. Alternaria solani
  3. Pythium aphanidermatum
  4. Phytophthora infestans Correct answer.

Explanation

Late blight of potato is caused by Phytophthora infestans, an oomycete that produces water-soaked lesions on leaves and can destroy the crop rapidly in cool, humid weather. Alternaria solani causes early blight, Rhizoctonia solani causes black scurf and stem canker, and Pythium aphanidermatum causes damping-off and root rots.

Question 33Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is a primary tillage implement?

  1. Cultivator
  2. Leveler
  3. Harrow
  4. Mouldboard plough Correct answer.

Explanation

Primary tillage opens up the soil and is done with implements such as the mouldboard plough, which cuts and inverts a furrow slice. Cultivators, harrows, and levelers are used for secondary tillage and seedbed preparation after the primary operation. The distinction is based on the depth and purpose of the operation.

Question 34Agriculture (professional knowledge for Agricultural Field Officer)

A farmer applies 200 kg of urea (46% N) per hectare to a maize crop. How much nitrogen is actually supplied per hectare?

  1. 92 kg N Correct answer.
  2. 200 kg N
  3. 46 kg N
  4. 108 kg N

Explanation

The nitrogen content of urea is 46%, so 200 kg urea supplies 200 × 0.46 = 92 kg N per hectare. The calculation uses the fertilizer grade rather than the total weight of the material. The other values either ignore the concentration or use the non-nitrogen fraction.

Question 35Agriculture (professional knowledge for Agricultural Field Officer)

In a sprinkler irrigation system, the uniformity of water application is most directly affected by which of the following factors?

  1. Depth of the water table
  2. Crop row direction
  3. Soil organic matter content
  4. Operating pressure and nozzle spacing Correct answer.

Explanation

Sprinkler uniformity depends mainly on the pressure at the nozzles, nozzle size, spacing of sprinklers along the lateral, and wind conditions. Correct pressure and spacing ensure overlapping patterns that even out application. Soil organic matter, row direction, and water-table depth influence infiltration and crop growth but not the sprinkler distribution pattern itself.

Question 36Agriculture (professional knowledge for Agricultural Field Officer)

A crop has a seasonal consumptive use of 600 mm and the effective rainfall during the season is 150 mm. If irrigation efficiency is 70%, what is the net irrigation requirement and the gross irrigation requirement?

  1. Net 450 mm; gross 643 mm Correct answer.
  2. Net 450 mm; gross 450 mm
  3. Net 600 mm; gross 857 mm
  4. Net 750 mm; gross 1071 mm

Explanation

Net irrigation requirement is consumptive use minus effective rainfall: 600 − 150 = 450 mm. Gross irrigation requirement is net divided by irrigation efficiency: 450 ÷ 0.70 = 643 mm. The other options either fail to subtract effective rainfall or fail to divide by efficiency.

Question 37Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the most appropriate method for estimating the genetic advance expected from selection for a quantitative trait?

  1. Genetic advance = phenotypic variance ÷ environmental variance
  2. Genetic advance = genotypic variance × environmental variance
  3. Genetic advance = selection differential × heritability Correct answer.
  4. Genetic advance = selection differential ÷ heritability

Explanation

Genetic advance under selection is the product of the selection differential and the heritability of the trait, often expressed as GA = i × σp × h². It estimates the gain in the next generation when selecting the top performers. The other formulas do not represent the response to selection.

Question 38Agriculture (professional knowledge for Agricultural Field Officer)

In a seed production programme, which of the following is the correct sequence of seed classes from the breeder's original seed to the seed sold to farmers?

  1. Breeder seed → Certified seed → Foundation seed
  2. Breeder seed → Foundation seed → Certified seed Correct answer.
  3. Foundation seed → Breeder seed → Certified seed
  4. Certified seed → Foundation seed → Breeder seed

Explanation

The seed multiplication chain starts with breeder seed, which is used to produce foundation seed, and foundation seed is then multiplied to certified seed for distribution to farmers. Each class has defined genetic purity standards and is produced under certification. The other sequences reverse or skip steps in the chain.

Question 39Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the most important reason for practicing crop rotation with a non-host crop to manage a soil-borne pathogen?

  1. It increases the nitrogen content of the soil
  2. It improves the physical structure of the soil
  3. It attracts beneficial insects to the field
  4. It reduces the pathogen inoculum in the soil over time Correct answer.

Explanation

A non-host crop interrupts the life cycle of a soil-borne pathogen by depriving it of a susceptible host, so inoculum declines over successive seasons. Nitrogen fixation, soil structure improvement, and beneficial insects may be side benefits but are not the primary mechanism for disease management. The effectiveness depends on the pathogen's host range and survival structures.

Question 40Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the correct interpretation of a soil test value of 0.5 dS/m for electrical conductivity of a saturation extract?

  1. The soil is highly acidic
  2. The soil is normal for most crops Correct answer.
  3. The soil is strongly saline
  4. The soil is sodic

Explanation

Electrical conductivity of the saturation extract below about 2 dS/m is generally considered normal for crop production. Values above 4 dS/m are classified as saline, and sodicity is assessed by exchangeable sodium percentage rather than EC. A value of 0.5 dS/m does not indicate salinity, sodicity, or acidity.

Question 41Agriculture (professional knowledge for Agricultural Field Officer)

In the context of integrated pest management, which of the following is an example of a cultural control method?

  1. Releasing Trichogramma egg parasitoids
  2. Adjusting sowing date to avoid peak pest incidence Correct answer.
  3. Using a light trap to monitor moths
  4. Spraying a synthetic pyrethroid

Explanation

Cultural control manipulates agronomic practices such as sowing date, crop rotation, and sanitation to reduce pest build-up. Adjusting sowing date to escape a pest's peak period is a classic cultural tactic. Trichogramma release is biological control, pyrethroid spray is chemical control, and light traps are monitoring tools.

Question 42Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the most appropriate storage practice to prevent insect infestation in stored wheat at farm level?

  1. Drying grain to safe moisture and storing in airtight containers Correct answer.
  2. Storing grain in open heaps under sunlight
  3. Mixing grain with fresh cow dung before storage
  4. Storing freshly harvested grain in jute bags in a damp room

Explanation

Safe storage requires drying wheat to about 12% moisture and keeping it in airtight, moisture-proof containers to prevent insect development and mould growth. Freshly harvested damp grain, open heaps, and unhygienic additives promote infestation and spoilage. Airtight storage also limits oxygen available to insects.

Question 43Agriculture (professional knowledge for Agricultural Field Officer)

A farmer wants to estimate the plant population of a crop in a field. The row spacing is 60 cm and plant-to-plant spacing within the row is 20 cm. What is the approximate plant population per hectare?

  1. 8,333 plants/ha
  2. 83,333 plants/ha Correct answer.
  3. 33,333 plants/ha
  4. 833,333 plants/ha

Explanation

The area per plant is 0.60 m × 0.20 m = 0.12 m². One hectare is 10,000 m², so the population is 10,000 ÷ 0.12 ≈ 83,333 plants per hectare. The other options result from errors in unit conversion or in multiplying rather than dividing by the area per plant.

Question 44Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the correct order of the zones of a typical soil profile from the surface downward?

  1. O horizon, A horizon, E horizon, B horizon, C horizon, R horizon Correct answer.
  2. C horizon, A horizon, B horizon, O horizon, E horizon, R horizon
  3. A horizon, O horizon, B horizon, E horizon, C horizon, R horizon
  4. O horizon, B horizon, A horizon, E horizon, R horizon, C horizon

Explanation

A generalized soil profile begins with the organic O horizon, followed by the mineral A horizon, the eluvial E horizon, the illuvial B horizon, the weathered parent material C horizon, and finally bedrock R horizon. This sequence reflects the direction of soil-forming processes from the surface downward. The other options place horizons out of their normal stratigraphic order.

Question 45Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the primary advantage of using a broad-bed furrow (BBF) system in rainfed Vertisol cultivation?

  1. It increases the soil pH permanently
  2. It allows continuous flooding of the field
  3. It eliminates the need for any fertilizer application
  4. It improves drainage and reduces waterlogging while conserving moisture in the bed Correct answer.

Explanation

Broad-bed and furrow systems on Vertisols separate the field into raised beds and furrows, so excess rainwater drains away while the beds retain moisture for crop roots. This reduces waterlogging and improves aeration in heavy clay soils. The system does not replace fertilizer, require flooding, or permanently change soil pH.

Question 46Agriculture (professional knowledge for Agricultural Field Officer)

In agricultural extension, which approach emphasizes working with farmer groups to identify their own problems and test locally adapted solutions?

  1. Technology transfer extension
  2. Regulatory extension
  3. Participatory extension Correct answer.
  4. Commodity-specialized extension

Explanation

Participatory extension involves farmers as partners in problem diagnosis, experimentation, and decision-making, often through farmer field schools or farmer research groups. Technology transfer is a top-down model, commodity-specialized extension focuses on a single crop or enterprise, and regulatory extension enforces rules. The participatory model is distinguished by farmer-led learning.

Question 47Agriculture (professional knowledge for Agricultural Field Officer)

A farmer has a field with a slope of 2% and wants to reduce soil erosion. Which of the following is the most appropriate mechanical measure?

  1. Flood irrigation
  2. Contour bunding Correct answer.
  3. Deep ploughing along the slope
  4. Removing all crop residues

Explanation

Contour bunding constructs small earthen bunds along the contour to slow runoff and trap sediment on gently sloping land. Ploughing along the slope, removing residues, and flood irrigation all increase erosion risk. The choice of measure depends on slope, rainfall, and soil type.

Question 48Agriculture (professional knowledge for Agricultural Field Officer)

Which of the following is the correct explanation of the term 'apomixis' in plant breeding?

  1. Seed formation without fertilization, producing progeny identical to the mother plant Correct answer.
  2. Development of fruit without seed formation
  3. Fertilization of the egg by two sperm nuclei
  4. Cross-pollination mediated by wind

Explanation

Apomixis is asexual seed formation in which the embryo develops without fertilization, so the offspring are genetically identical to the mother plant. It is of interest for fixing hybrid vigour in seed-propagated crops. Double fertilization, parthenocarpy, and wind pollination are different phenomena.

Question 49Agriculture (professional knowledge for Agricultural Field Officer)

In a disease forecasting system for a foliar pathogen, which combination of weather variables is most commonly used to predict a high risk of infection?

  1. Wind speed and solar radiation only
  2. Soil pH and organic matter
  3. Soil moisture and nitrogen status
  4. Leaf wetness duration and temperature Correct answer.

Explanation

Many foliar pathogens require a period of leaf wetness and a favourable temperature range for spore germination and infection, so these variables drive disease forecasting models. Soil pH, organic matter, and nitrogen status affect plant nutrition and some soil-borne diseases but are not the primary drivers of foliar infection events. Wind and radiation modify microclimate but are not sufficient alone.

Question 50Agriculture (professional knowledge for Agricultural Field Officer)

A crop is grown in a soil with a cation exchange capacity of 20 cmol(+)/kg and an exchangeable sodium percentage of 15. Which of the following is the most appropriate interpretation?

  1. The soil is acidic and needs liming
  2. The soil is normal and needs no amendment
  3. The soil is sodic and needs gypsum application Correct answer.
  4. The soil is saline and needs leaching with good drainage

Explanation

An exchangeable sodium percentage of 15 exceeds the usual threshold of 15% for sodic soils (some classifications use 15 as the boundary), indicating sodium dominance on the exchange complex. Such soils are reclaimed by applying gypsum, which supplies calcium to displace sodium, followed by leaching. Salinity is diagnosed from EC, and acidity from pH.