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BSEH Secondary Agriculture study materials
BSEH Secondary Agriculture study resources

BSEH Secondary Agriculture practice questions

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Question 1Agricultural Practices and Crop Production

Which soil property is improved most directly by adding well-decomposed organic manure to a sandy field?

  1. Bulk density of the bedrock
  2. Depth of the water table
  3. Water-holding capacity Correct answer.
  4. Soil pH

Explanation

Organic matter raises the water-holding capacity of coarse sandy soils because humus and the aggregates it forms retain moisture in pores that would otherwise drain freely. It also supports microbial activity and nutrient exchange. Bedrock bulk density and water-table depth are geological features unaffected by manure application.

Question 2Agricultural Practices and Crop Production

A farmer wants to sow maize seed at a depth that balances moisture availability with emergence. Which sowing depth is generally recommended for maize on a moist loam soil?

  1. 10 to 12 cm
  2. 4 to 6 cm Correct answer.
  3. 15 to 18 cm
  4. 1 to 2 cm

Explanation

Maize seed is typically placed about 4 to 6 cm deep in moist loam, which keeps the seed in contact with adequate moisture while still allowing the coleoptile to reach the surface. Very shallow sowing dries out quickly, while very deep sowing exhausts seed reserves before emergence.

Question 3Agricultural Practices and Crop Production

Which practice best reduces soil erosion on a sloping cultivated field during the rainy season?

  1. Leaving the field bare between seasons
  2. Planting cover crops and contour strips Correct answer.
  3. Burning crop residues after harvest
  4. Ploughing up and down the slope

Explanation

Cover crops protect the soil surface from raindrop impact, and contour strips slow runoff so water infiltrates rather than carrying topsoil downhill. Together they cut both splash and rill erosion. Bare or up-and-down-slope cultivation accelerates runoff and soil loss.

Question 4Agricultural Practices and Crop Production

Which group of organisms is chiefly responsible for converting atmospheric nitrogen into forms plants can use in the root nodules of legumes?

  1. Denitrifying bacteria
  2. Mycorrhizal fungi
  3. Rhizobium bacteria Correct answer.
  4. Nitrifying bacteria

Explanation

Rhizobium bacteria live symbiotically in legume root nodules and fix atmospheric nitrogen into ammonia that the plant can assimilate. Mycorrhizal fungi aid phosphorus uptake, while nitrifying and denitrifying bacteria act on nitrogen already present in the soil.

Question 5Agricultural Practices and Crop Production

What is the primary purpose of seed treatment with a fungicide before sowing?

  1. To break seed dormancy
  2. To increase seed size
  3. To supply nitrogen to the young plant
  4. To protect germinating seedlings from soil-borne and seed-borne pathogens Correct answer.

Explanation

Fungicidal seed treatment coats the seed to suppress seed-borne and soil-borne pathogens that attack during germination and early establishment. It does not supply nutrients, change seed size, or serve as a dormancy-breaking treatment.

Question 6Agricultural Practices and Crop Production

Which irrigation method generally gives the highest water-use efficiency in a widely spaced orchard crop?

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

Explanation

Drip irrigation delivers water directly to the root zone in small, frequent amounts, minimising evaporation, runoff, and deep percolation, so it achieves high water-use efficiency. Flood and furrow methods wet large areas and lose much water to evaporation and drainage.

Question 7Agricultural Practices and Crop Production

Which macronutrient is most closely associated with root development, flowering, and fruiting in crop plants?

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

Explanation

Potassium regulates water balance, enzyme activity, and carbohydrate transport and is strongly linked with root strength, flowering, and fruit quality. Nitrogen mainly drives vegetative growth, while phosphorus supports early root and energy metabolism and calcium supports cell wall structure.

Question 8Agricultural Practices and Crop Production

Which crop is a legume commonly grown for both grain and nitrogen fixation in rotation?

  1. Maize
  2. Sorghum
  3. Cowpea Correct answer.
  4. Cassava

Explanation

Cowpea is a legume that forms nodules with Rhizobium and fixes nitrogen, making it valuable in rotations for both grain and soil improvement. Maize, cassava, and sorghum are non-legumes and do not fix atmospheric nitrogen.

Question 9Agricultural Practices and Crop Production

A farmer applies a nitrogen fertilizer to a maize field just before heavy rainfall is forecast. What is the most likely consequence?

  1. Reduced weed competition
  2. Improved soil structure
  3. Leaching and volatilisation losses of nitrogen Correct answer.
  4. Increased nitrogen use efficiency

Explanation

Applying nitrogen shortly before heavy rain risks leaching of nitrate below the root zone and volatilisation or denitrification losses, lowering efficiency. Timing applications to crop demand and avoiding imminent heavy rain conserve the nutrient.

Question 10Agricultural Practices and Crop Production

Which factor most strongly determines the length of the critical weed-free period in a maize crop?

  1. Soil parent material
  2. Crop growth rate and canopy closure timing Correct answer.
  3. Colour of the maize leaves
  4. Time of fertilizer manufacture

Explanation

The critical weed-free period depends on how quickly the crop establishes a canopy that suppresses weeds and on its competitive ability and growth rate. Fast canopy closure shortens the period during which weeds must be controlled. Leaf colour, parent material, and fertilizer manufacture timing do not determine it.

Question 11Agricultural Practices and Crop Production

In a crop rotation, why is it recommended to alternate cereals with legumes and root crops?

  1. To break pest and disease cycles and balance nutrient use Correct answer.
  2. To maintain the same pest and disease cycle
  3. To ensure the same nutrients are depleted each season
  4. To reduce soil organic matter

Explanation

Alternating crop families disrupts the life cycles of pests and pathogens that are host-specific and balances nutrient uptake, with legumes adding nitrogen. This improves soil health and reduces reliance on chemical control.

Question 12Agricultural Practices and Crop Production

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

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

Explanation

Magnesium is mobile in the plant, so deficiency appears first on older leaves as interveinal chlorosis while veins stay green. Iron deficiency typically appears on young leaves, and calcium and boron deficiencies cause distortion of growing points rather than interveinal yellowing of older leaves.

Question 13Agricultural Practices and Crop Production

Which pest management approach relies on releasing natural enemies such as parasitic wasps into a crop?

  1. Cultural control
  2. Biological control Correct answer.
  3. Chemical control
  4. Mechanical control

Explanation

Biological control uses living organisms, including predators and parasitoids, to suppress pest populations. Cultural control modifies practices such as planting dates, and mechanical control uses physical removal or barriers.

Question 14Agricultural Practices and Crop Production

Why is it important to dry harvested grain to a safe moisture content before storage?

  1. To improve the germination of stored seed
  2. To prevent mould growth and insect infestation Correct answer.
  3. To make the grain more attractive in colour
  4. To increase grain weight

Explanation

Drying grain to a safe moisture level limits fungal growth and insect activity that cause spoilage and mycotoxin production. Moist grain heats and moulds rapidly in storage. Drying does not increase weight or improve appearance as a primary purpose.

Question 15Agricultural Practices and Crop Production

A farmer wants to control a soil-borne pathogen that persists on crop residues. Which cultural practice most directly reduces the pathogen population in the soil?

  1. Irrigating more frequently
  2. Applying more nitrogen fertilizer
  3. Incorporating a non-host break crop and managing residues Correct answer.
  4. Increasing plant density

Explanation

Using a non-host break crop starves the pathogen of its host, and residue management removes the substrate on which it survives. Together these reduce the soil population over time. Higher density, extra nitrogen, or irrigation do not target the pathogen directly and may worsen disease.

Question 16Agricultural Practices and Crop Production

What is the main advantage of using certified seed rather than seed saved from the previous harvest?

  1. Certified seed requires no fertilizer
  2. Certified seed is always cheaper
  3. Certified seed never needs pest control
  4. Certified seed has verified purity, germination, and health standards Correct answer.

Explanation

Certified seed has been tested and verified for genetic purity, germination percentage, and freedom from specified seed-borne diseases and weed seeds. This gives more reliable establishment and yield, though it costs more and still requires normal crop management.

Question 17Agricultural Practices and Crop Production

Which soil textural class generally has the greatest cation exchange capacity and ability to retain nutrients?

  1. Silt loam
  2. Clay Correct answer.
  3. Loamy sand
  4. Sandy loam

Explanation

Clay particles carry the highest surface charge and surface area among soil separates, so clay soils generally have the greatest cation exchange capacity and nutrient retention. Sandy soils retain fewer nutrients because their particles have little charge and low surface area.

Question 18Agricultural Practices and Crop Production

Which practice is most effective for breaking seed dormancy in a hard-seeded legume?

  1. Mechanical scarification or hot water treatment Correct answer.
  2. Soaking in cold water
  3. Exposing the seed to light
  4. Storing in a moist warm place

Explanation

Hard seed coats restrict water uptake, so scarifying the coat mechanically or with hot water allows imbibition and germination. Cold soaking or light exposure does not overcome an impermeable seed coat.

Question 19Agricultural Practices and Crop Production

A farmer notices that maize plants in a field are stunted with purple-tinged leaves and poor root development. Which nutrient deficiency is most likely?

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

Explanation

Phosphorus deficiency commonly causes stunted growth with purple or reddish discolouration of leaves, especially in young plants, and poor root development. Nitrogen deficiency mainly causes general yellowing, while potassium deficiency causes leaf-edge scorch.

Question 20Agricultural Practices and Crop Production

Which cropping system most closely matches the description of growing two or more crops together in the same field in a defined arrangement?

  1. Intercropping Correct answer.
  2. Monoculture
  3. Fallow
  4. Relay cropping

Explanation

Intercropping is the cultivation of two or more crops simultaneously in the same field in a defined spatial arrangement. Monoculture grows one crop, fallow leaves land uncropped, and relay cropping overlaps the end of one crop with the start of another in sequence.

Question 21Agricultural Practices and Crop Production

A grower applies urea to a calcareous soil and leaves it on the surface without incorporation or rain. Which loss pathway is most likely to reduce nitrogen availability?

  1. Immobilisation by earthworms
  2. Volatilisation of ammonia Correct answer.
  3. Leaching of nitrate
  4. Fixation by Rhizobium

Explanation

Urea applied to the surface of a calcareous, alkaline soil hydrolyses to ammonium, and without incorporation or rainfall the ammonium can be converted to ammonia gas and lost by volatilisation. Leaching requires nitrate formation and downward water movement, which is not occurring here.

Question 22Agricultural Practices and Crop Production

A field has a long history of continuous maize and shows increasing damage from a soil-borne root pathogen. Which strategy best combines short-term control with long-term reduction of the pathogen?

  1. Applying more nitrogen to outgrow the disease
  2. Rotating with a non-host crop and using resistant varieties Correct answer.
  3. Applying the same fungicide every season
  4. Increasing maize plant density

Explanation

Combining a non-host rotation with resistant varieties reduces the pathogen population in the soil and limits infection of the current crop. Repeated use of the same fungicide selects for resistance, while higher density or nitrogen does not address the pathogen.

Question 23Agricultural Practices and Crop Production

In a comparison of irrigation scheduling methods, which approach best accounts for both soil moisture status and crop water demand?

  1. Irrigating on a fixed weekly calendar
  2. Irrigating only after plants show visible wilting
  3. Irrigating when the soil moisture deficit reaches a threshold set from evapotranspiration estimates Correct answer.
  4. Irrigating whenever the soil surface appears dry

Explanation

Scheduling that combines measured or estimated evapotranspiration with soil moisture thresholds matches water supply to actual crop demand and avoids both under- and over-irrigation. Fixed calendars ignore weather, surface dryness can be misleading, and waiting for wilting imposes stress.

Question 24Agricultural Practices and Crop Production

A farmer harvests a cereal crop at high moisture and stores it in a sealed silo. After several weeks the grain heats and develops a musty odour. Which explanation best accounts for this outcome?

  1. Insects removed moisture from the grain
  2. Fungal and microbial activity raised temperature and produced mycotoxins Correct answer.
  3. The grain respired aerobically and dried out
  4. The grain absorbed extra nitrogen from the air

Explanation

Moist grain in a sealed silo supports rapid fungal and microbial growth, which generates heat and off-odours and can produce mycotoxins, causing spoilage. The problem is excess moisture, not an external nitrogen source or insect drying.

Question 25Agricultural Practices and Crop Production

Which statement best explains why a legume in rotation can reduce the nitrogen fertilizer requirement of the following cereal crop?

  1. The legume lowers the soil pH permanently
  2. The legume removes all soil pathogens
  3. The legume leaves residual fixed nitrogen in the soil and residues Correct answer.
  4. The legume increases soil bulk density

Explanation

A legume fixes atmospheric nitrogen in symbiosis with Rhizobium, and some of that nitrogen remains in roots and residues and becomes available to the following cereal. This can reduce the fertilizer nitrogen needed, though the amount depends on the legume and how residues are managed.

Question 26Agricultural Practices and Crop Production

A grower wants to reduce soil erosion on a sloping field between main crops. Which practice is most directly suited to protecting the soil surface during this period?

  1. Removing all vegetation to expose bare soil
  2. Deep ploughing to bury the topsoil
  3. Planting a fast-growing cover crop to shield the surface Correct answer.
  4. Burning crop residues to clear the field

Explanation

A cover crop establishes ground cover that intercepts raindrop impact and slows runoff, so soil particles are not detached and carried downslope. Bare or burned surfaces leave soil exposed, and ploughing loosens it further, increasing rather than reducing erosion risk.

Question 27Agricultural Practices and Crop Production

Which term describes the practice of growing a single crop species in a field season after season?

  1. Intercropping
  2. Mixed farming
  3. Relay cropping
  4. Monoculture Correct answer.

Explanation

Monoculture is the repeated cultivation of one crop species on the same land, which can simplify management but tends to build up pest and disease pressure. Intercropping and relay cropping both involve more than one species, and mixed farming combines crops with livestock.

Question 28Agricultural Practices and Crop Production

Which piece of information is most important to record when collecting a soil sample for laboratory analysis?

  1. The depth and location from which the sample was taken Correct answer.
  2. The time of day the laboratory opens
  3. The colour of the sampling bucket used
  4. The name of the person who delivered the sample

Explanation

Nutrient levels and other soil properties vary strongly with depth and position in the field, so a result is only interpretable if the sampling depth and location are recorded. Bucket colour, courier identity and laboratory opening hours do not influence the analytical result.

Question 29Agricultural Practices and Crop Production

Which plant part is primarily responsible for absorbing water and dissolved mineral nutrients from the soil?

  1. Flower petals
  2. Root hairs Correct answer.
  3. Stem nodes
  4. Leaf blades

Explanation

Root hairs are fine extensions of epidermal cells that greatly increase the absorbing surface area of the root and take up water and minerals. Leaves are mainly sites of photosynthesis and transpiration, stems provide support and transport, and petals are reproductive structures.

Question 30Agricultural Practices and Crop Production

A grower wants to sow a cereal at a target plant population of 300 plants per square metre. If laboratory germination is 90 percent and field establishment is expected to be 80 percent of viable seeds, approximately how many seeds per square metre should be sown?

  1. 417 Correct answer.
  2. 270
  3. 240
  4. 300

Explanation

The viable-and-establishing fraction is 0.90 multiplied by 0.80, which equals 0.72. Dividing the target population of 300 by 0.72 gives about 417 seeds per square metre, so sowing 417 compensates for both germination and establishment losses.

Question 31Agricultural Practices and Crop Production

A farmer wants to schedule irrigation for a vegetable crop grown on a sandy loam. Which approach best matches water application to actual crop demand?

  1. Irrigating on the same fixed calendar day each week regardless of weather
  2. Applying water only when plants visibly wilt
  3. Flooding the field once at the start of the season
  4. Replacing estimated evapotranspiration losses using soil moisture monitoring Correct answer.

Explanation

Scheduling that replaces estimated crop evapotranspiration, checked against measured soil moisture, applies water in step with actual demand and avoids both under- and over-irrigation. Fixed calendars, visible wilting and a single flooding ignore weather, soil storage and crop stage.

Question 32Agricultural Practices and Crop Production

A grower plans to control a grass weed in a broadleaf vegetable crop. Which herbicide characteristic is most important to check before use?

  1. The manufacturer's country of registration
  2. Selectivity for the crop and the spectrum of weeds controlled Correct answer.
  3. The size of the container supplied
  4. The colour of the product label

Explanation

Herbicide choice depends on whether the product selectively controls the target weed without injuring the crop, and on whether it covers the weed spectrum present. Label colour, container size and registration country do not determine biological fit.

Question 33Agricultural Practices and Crop Production

A farmer wants to store freshly harvested paddy safely for several months. Which combination of conditions best reduces storage losses?

  1. High grain moisture and warm, humid storage
  2. High grain moisture and sealed, unventilated bins
  3. Low grain moisture and warm, humid, unventilated storage
  4. Low grain moisture and cool, dry, well-ventilated storage Correct answer.

Explanation

Moulds and insects develop fastest when grain is damp and warm, so drying to a safe moisture content and keeping the store cool, dry and ventilated minimises spoilage. High moisture or warm humid conditions promote heating, mould and insect multiplication.

Question 34Agricultural Practices and Crop Production

A farmer observes that a crop grown after a legume needs less nitrogen fertilizer than the same crop grown after a cereal. Which process best explains this?

  1. Biological nitrogen fixation by rhizobia in the legume root nodules Correct answer.
  2. Greater phosphorus release from legume residues
  3. Reduced leaching under legume canopies
  4. Faster decomposition of cereal straw

Explanation

Rhizobia in nodules on legume roots convert atmospheric nitrogen into forms the plant can use, and part of that nitrogen remains in residues and roots for the following crop. The benefit is a nitrogen effect rather than a phosphorus or leaching effect.

Question 35Agricultural Practices and Crop Production

A farmer wants to reduce the risk of a soil-borne disease building up in a continuously cropped field. Which strategy is most appropriate?

  1. Applying more nitrogen to the same crop each season
  2. Irrigating more frequently with the same crop
  3. Increasing plant density of the same susceptible crop
  4. Rotating with non-host crops and incorporating resistant varieties Correct answer.

Explanation

Soil-borne pathogens build up when a susceptible host is present repeatedly, so rotating to non-host crops starves the pathogen and resistant varieties limit infection. Intensifying the same crop, adding nitrogen or irrigating more does not remove the host and may worsen the problem.

Question 36Agricultural Practices and Crop Production

A grower wants to compare two maize varieties for yield. Which approach gives the most reliable comparison?

  1. Growing each variety in a different field in different years
  2. Growing both varieties in replicated plots within the same field and season Correct answer.
  3. Comparing yields reported on the two seed bags
  4. Growing one variety and estimating the other from memory

Explanation

Replication within the same field and season controls for soil variation and weather, so differences can be attributed to variety rather than environment. Different fields, different years, bag claims or memory introduce confounding factors.

Question 37Agricultural Practices and Crop Production

A farmer applies farmyard manure to a field. Which benefit is most directly associated with the organic matter it adds?

  1. Immediate elimination of all soil-borne pathogens
  2. Complete replacement of mineral fertilizer in all crops
  3. Improved soil structure and water-holding capacity Correct answer.
  4. Permanent increase in soil pH to alkaline levels

Explanation

Organic matter from manure binds soil particles into stable aggregates, improving aeration, infiltration and water retention. Manure does not sterilise soil, does not permanently raise pH, and cannot fully replace mineral fertilizer in all situations.

Question 38Agricultural Practices and Crop Production

A grower wants to establish a pasture on a degraded, compacted field. Which sequence of operations is most logical?

  1. Sow seed first, then assess compaction and fertility later
  2. Apply herbicide and leave the field bare for a season
  3. Increase grazing pressure to break the surface
  4. Assess and correct compaction, test and amend soil fertility, then sow a suitable species mixture Correct answer.

Explanation

Compacted soil restricts root growth and water movement, so relieving compaction and correcting fertility before sowing gives seedlings a better chance to establish. Sowing first, leaving the field bare or increasing grazing pressure does not address the underlying limitations.

Question 39Agricultural Practices and Crop Production

A farmer notices that a crop shows poor growth despite adequate rainfall and no visible pest damage. A soil test reports very low organic matter and low cation exchange capacity. Which interpretation is most consistent with these observations?

  1. The crop has an adequate supply of all nutrients
  2. The soil has limited ability to retain nutrients, so applied nutrients are readily leached Correct answer.
  3. The soil pH must be strongly alkaline
  4. The crop is suffering from excess phosphorus fixation by organic matter

Explanation

Low organic matter and low cation exchange capacity mean the soil holds few exchangeable nutrients, so mobile nutrients can leach away and the crop cannot access a steady supply. This explains poor growth even with adequate moisture and no pests.

Question 40Agricultural Practices and Crop Production

Two fields receive the same amount of nitrogen fertilizer, but the field with a history of heavy irrigation and sandy soil shows lower crop nitrogen uptake. Which explanation is most plausible?

  1. Nitrogen fertilizer is not needed on sandy soils
  2. The crop in the sandy field has a lower nitrogen requirement
  3. The sandy field has a higher cation exchange capacity that binds nitrate
  4. Nitrate has leached below the root zone in the sandy, heavily irrigated field Correct answer.

Explanation

Nitrate is mobile and negatively charged, so it is not held on cation exchange sites and moves readily with drainage water. Sandy soils have low water-holding and exchange capacity, so heavy irrigation can push nitrate below the roots, reducing uptake.

Question 41Soil Science and Soil Management

A soil sample has a bulk density of 1.4 g/cm³ and a particle density of 2.8 g/cm³. What is its approximate porosity?

  1. 50% Correct answer.
  2. 25%
  3. 40%
  4. 70%

Explanation

Porosity equals 1 minus the ratio of bulk density to particle density, so 1 − (1.4/2.8) = 0.50, or 50%. This means half the soil volume is pore space available for air and water.

Question 42Soil Science and Soil Management

Which soil particle size class is defined as having a diameter between 0.002 mm and 0.05 mm in the USDA system?

  1. Sand
  2. Silt Correct answer.
  3. Gravel
  4. Clay

Explanation

In the USDA system silt particles range from 0.002 mm to 0.05 mm in diameter. Clay is smaller than 0.002 mm and sand is larger, from 0.05 to 2.0 mm.

Question 43Soil Science and Soil Management

A farmer's field tests at pH 5.2 with high exchangeable aluminum. Which amendment most directly corrects this condition?

  1. Elemental sulfur
  2. Agricultural lime Correct answer.
  3. Ammonium sulfate
  4. Gypsum

Explanation

Agricultural lime (calcium carbonate) neutralizes soil acidity and precipitates toxic exchangeable aluminum. Raising pH toward 6.0–6.5 reduces aluminum solubility and improves conditions for most crops.

Question 44Soil Science and Soil Management

Which soil horizon is the zone of maximum accumulation of illuviated clay, iron, or aluminum oxides?

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

Explanation

The B horizon is the subsoil zone where materials leached from overlying horizons accumulate, a process called illuviation. Accumulation of clay, iron, or aluminum oxides is characteristic of this horizon.

Question 45Soil Science and Soil Management

Which soil structure type is most favorable for root penetration and water movement in a surface soil?

  1. Massive
  2. Columnar
  3. Granular Correct answer.
  4. Platy

Explanation

Granular structure consists of small, rounded aggregates that create abundant pore space for air, water, and roots. It is typical of productive surface horizons high in organic matter.

Question 46Soil Science and Soil Management

A soil has a cation exchange capacity of 20 cmol(+)/kg and is 60% base saturated. What is the approximate amount of exchangeable basic cations in cmol(+)/kg?

  1. 32
  2. 8
  3. 20
  4. 12 Correct answer.

Explanation

Base saturation is the proportion of the cation exchange capacity occupied by basic cations. Multiplying 20 cmol(+)/kg by 0.60 gives 12 cmol(+)/kg of exchangeable bases.

Question 47Soil Science and Soil Management

Which practice most effectively reduces soil erosion on a steep cultivated slope?

  1. Planting rows up and down the slope
  2. Increasing tillage depth
  3. Contour strip cropping Correct answer.
  4. Leaving the field bare after harvest

Explanation

Contour strip cropping alternates strips of close-growing vegetation with cultivated crops along the contour, slowing runoff and trapping sediment. It reduces both sheet and rill erosion on sloping land.

Question 48Soil Science and Soil Management

Which macronutrient is most commonly deficient in alkaline, calcareous soils because it forms insoluble compounds at high pH?

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

Explanation

In calcareous soils with high pH, phosphorus precipitates as calcium phosphate minerals, reducing its plant availability. This is a common reason phosphorus is banded rather than broadcast in such soils.

Question 49Soil Science and Soil Management

Which term describes the water content remaining in soil after gravity drainage has ceased and field capacity is reached?

  1. Permanent wilting point
  2. Hygroscopic water
  3. Field capacity Correct answer.
  4. Saturation

Explanation

Field capacity is the water content remaining after free drainage has removed gravitational water, typically about two days after saturation. It represents the upper limit of plant-available water under normal drainage.

Question 50Soil Science and Soil Management

A soil test reports 30 kg/ha of available phosphorus, and the recommended rate for the target crop is 60 kg/ha. How much phosphorus fertilizer should be applied to meet the shortfall?

  1. 90 kg/ha
  2. 30 kg/ha Correct answer.
  3. 0 kg/ha
  4. 60 kg/ha

Explanation

The shortfall is the recommended rate minus the available amount, so 60 − 30 = 30 kg/ha. This is the amount needed to bring the soil to the recommended level.