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Odisha CHSE +2 Vocational Crop Production study materials
Odisha CHSE +2 Vocational Crop Production study resources

Odisha CHSE +2 Vocational Crop Production practice questions

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Question 1Introduction to Crop Production and Agronomy Fundamentals

In agronomy, the term 'cropping intensity' refers to which of the following?

  1. The depth to which ploughing is carried out before sowing
  2. The total weight of produce harvested from one hectare in a single season
  3. The number of crops grown on the same field in one agricultural year, expressed as a percentage of the standard single-crop year Correct answer.
  4. The proportion of a crop's biomass that is converted into economic yield

Explanation

Cropping intensity measures how many crops are raised on the same land within one year, usually expressed as a percentage where one crop per year equals 100 per cent. Multiple cropping raises this value above 100, indicating more intensive use of the land.

Question 2Introduction to Crop Production and Agronomy Fundamentals

A farmer in coastal Odisha wants to classify the crop grown between the main kharif and rabi seasons using residual soil moisture. Which cropping term best describes such a crop?

  1. Catch crop
  2. Mixed crop
  3. Relay crop
  4. Zaid crop Correct answer.

Explanation

Zaid or summer crops are short-duration crops grown in the gap between rabi and kharif, often on residual moisture or with limited irrigation. Catch crops are grown to utilise a short window before the main crop, while relay and mixed cropping involve overlapping or simultaneous growth.

Question 3Introduction to Crop Production and Agronomy Fundamentals

Which soil property is most directly improved by adding organic matter such as farmyard manure to a sandy loam field?

  1. Bulk density of the mineral fraction
  2. Depth of the underlying parent rock
  3. Water-holding capacity and cation exchange capacity Correct answer.
  4. Particle density of the sand grains

Explanation

Organic matter increases aggregation and the number of exchange sites, so both water retention and cation exchange capacity rise. It does not alter the density of individual mineral particles or the depth of parent material.

Question 4Introduction to Crop Production and Agronomy Fundamentals

A soil test reports a pH of 5.2 for a field intended for a rabi pulse crop. Which amendment is most appropriate to raise the pH towards neutrality?

  1. Elemental sulphur
  2. Gypsum
  3. Ammonium sulphate
  4. Agricultural lime Correct answer.

Explanation

Acidic soils are corrected by applying lime, usually ground limestone, which neutralises hydrogen ions and raises pH. Gypsum supplies calcium without raising pH, while sulphur and ammonium sulphate are acidifying.

Question 5Introduction to Crop Production and Agronomy Fundamentals

In the classification of tillage operations, which implement is primarily used for primary tillage in a paddy field?

  1. Leveller
  2. Mouldboard plough Correct answer.
  3. Cultivator
  4. Disc harrow

Explanation

Primary tillage opens up the soil to a considerable depth and is done with implements such as the mouldboard plough. Harrows, cultivators and levellers are secondary tillage tools used for finer preparation.

Question 6Introduction to Crop Production and Agronomy Fundamentals

Which of the following best explains why puddling is practised before transplanting rice?

  1. It increases soil aeration for root respiration
  2. It reduces water percolation losses and eases transplanting Correct answer.
  3. It raises soil temperature during winter
  4. It increases the bulk density of the plough layer

Explanation

Puddling destroys soil structure and creates a low-permeability layer that reduces percolation, conserving water, while the soft mud makes transplanting easy. It actually decreases aeration rather than increasing it.

Question 7Introduction to Crop Production and Agronomy Fundamentals

Which of the following is a leguminous pulse crop commonly grown in Odisha that can fix atmospheric nitrogen through root nodules?

  1. Sesame
  2. Maize
  3. Black gram Correct answer.
  4. Jute

Explanation

Black gram is a legume that forms symbiotic nodules with Rhizobium and fixes atmospheric nitrogen. Sesame, maize and jute are non-legumes and do not fix nitrogen symbiotically.

Question 8Introduction to Crop Production and Agronomy Fundamentals

A crop is described as being grown for its 'economic yield' of underground stem tubers. Which crop fits this description?

  1. Mustard
  2. Groundnut
  3. Ginger Correct answer.
  4. Sweet potato

Explanation

Ginger is grown for its underground rhizome, a modified stem that forms the economic yield. Sweet potato and groundnut yield root and pod respectively, while mustard yields seed.

Question 9Introduction to Crop Production and Agronomy Fundamentals

Which of the following statements about the critical period of crop-weed competition is correct?

  1. It is the time taken by a herbicide to kill weeds
  2. It is the period during which weed competition most reduces final crop yield Correct answer.
  3. It is the period after crop harvest when weeds set seed
  4. It is the entire life span of the crop from sowing to harvest

Explanation

The critical period is the interval in which weeds must be controlled to prevent unacceptable yield loss, usually early in crop growth. Weed competition outside this window has a smaller effect on final yield.

Question 10Introduction to Crop Production and Agronomy Fundamentals

An agronomist recommends a herbicide that kills only grasses while leaving broad-leaved crops unharmed. Such a herbicide is classified as which type?

  1. Soil sterilant
  2. Non-selective herbicide
  3. Contact herbicide
  4. Selective herbicide Correct answer.

Explanation

Selective herbicides kill certain plant groups while sparing others, which is why a grass-killer can be used in a broad-leaved crop. Non-selective herbicides kill most vegetation, and soil sterilants prevent all growth.

Question 11Introduction to Crop Production and Agronomy Fundamentals

A farmer applies 120 kg of urea to one hectare. Approximately how much nitrogen does this supply, given that urea contains about 46 per cent nitrogen?

  1. 27.6 kg
  2. 46.0 kg
  3. 120.0 kg
  4. 55.2 kg Correct answer.

Explanation

Nitrogen supplied equals the quantity of urea multiplied by its nitrogen fraction, that is 120 times 0.46, which gives about 55.2 kg of nitrogen. The remaining mass is mainly carbon, oxygen and hydrogen.

Question 12Introduction to Crop Production and Agronomy Fundamentals

Which nutrient is described as a secondary nutrient in plant nutrition?

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

Explanation

Calcium, along with magnesium and sulphur, is classed as a secondary nutrient because plants need it in moderate amounts. Nitrogen is a primary nutrient, while zinc and boron are micronutrients.

Question 13Introduction to Crop Production and Agronomy Fundamentals

In a crop rotation plan, which sequence best illustrates the principle of alternating deep-rooted and shallow-rooted crops?

  1. Cotton followed by wheat followed by cotton Correct answer.
  2. Potato followed by potato followed by potato
  3. Rice followed by rice followed by rice
  4. Maize followed by maize followed by maize

Explanation

A good rotation alternates crops with different rooting depths and nutrient demands, such as a deep-rooted cotton followed by a shallow-rooted wheat. Continuous cropping of a single species depletes the same soil layer and encourages pests.

Question 14Introduction to Crop Production and Agronomy Fundamentals

Which of the following describes the principle of 'minimum tillage'?

  1. Applying herbicides instead of any cultivation
  2. Ploughing to the maximum possible depth to improve drainage
  3. Reducing soil disturbance to the minimum needed for crop establishment Correct answer.
  4. Ploughing only when weeds are present

Explanation

Minimum tillage limits soil disturbance to what is required for seed placement and establishment, conserving moisture, structure and organic matter. It is not about maximum depth or purely replacing cultivation with chemicals.

Question 15Introduction to Crop Production and Agronomy Fundamentals

Which of the following is the primary reason for treating seed with a fungicide before sowing?

  1. To protect emerging seedlings from soil-borne and seed-borne pathogens Correct answer.
  2. To break dormancy in freshly harvested seed
  3. To supply nitrogen to the young seedling
  4. To increase the germination percentage of the seed lot

Explanation

Seed treatment with fungicide coats the seed and protects the germinating seedling from pathogens carried on the seed or present in the soil. It does not add nutrients or break dormancy.

Question 16Introduction to Crop Production and Agronomy Fundamentals

Which of the following best describes 'seed rate' in crop production?

  1. The weight or number of seeds sown per unit area of land Correct answer.
  2. The percentage of seeds that germinate in a laboratory test
  3. The spacing maintained between two adjacent rows
  4. The depth at which seeds are placed in the soil

Explanation

Seed rate is the quantity of seed, by weight or number, sown over a given area to achieve the desired plant population. Germination percentage, row spacing and sowing depth are separate seed and planting parameters.

Question 17Introduction to Crop Production and Agronomy Fundamentals

A farmer wants to reduce soil erosion on a sloping field in the Eastern Ghats. Which agronomic measure is most directly effective?

  1. Increasing the depth of ploughing each season
  2. Growing crops in contour strips with a cover crop between them Correct answer.
  3. Sowing crops in rows running straight up and down the slope
  4. Removing all crop residues after harvest

Explanation

Contour strip cropping with cover reduces the length of slope and slows runoff, cutting soil loss. Rows running up and down the slope, residue removal and deep ploughing all accelerate erosion.

Question 18Introduction to Crop Production and Agronomy Fundamentals

Which of the following combinations correctly matches a crop with its most common season of cultivation in Odisha?

  1. Mustard with kharif
  2. Wheat with kharif
  3. Groundnut with rabi as the main season
  4. Rice with kharif Correct answer.

Explanation

Rice is the principal kharif crop in Odisha, sown with the onset of the monsoon. Wheat and mustard are mainly rabi crops, and groundnut is predominantly a kharif crop in the state.

Question 19Introduction to Crop Production and Agronomy Fundamentals

In the context of plant nutrients, what does the term 'luxury consumption' mean?

  1. Uptake of a nutrient beyond the amount needed for optimum growth without increasing yield Correct answer.
  2. The uptake of water along with dissolved nutrients
  3. Uptake of nutrients only when they are supplied through organic manure
  4. The loss of nutrients through leaching below the root zone

Explanation

Luxury consumption occurs when a plant absorbs more of a nutrient than it needs for maximum growth, so the extra uptake does not raise yield. Potassium is a classic example. This is wasteful and should be avoided through balanced fertilisation.

Question 20Introduction to Crop Production and Agronomy Fundamentals

Which of the following statements about intercropping is correct?

  1. Two or more crops are grown simultaneously in distinct rows on the same field Correct answer.
  2. The next crop is sown before the harvest of the standing crop
  3. A single crop is grown repeatedly on the same field for several years
  4. Two or more crops are grown one after another in the same season

Explanation

Intercropping involves growing two or more crops simultaneously on the same field in a definite row arrangement. Growing crops one after another is sequential cropping, repeated single cropping is monoculture, and sowing into a standing crop is relay cropping.

Question 21Soil Science, Soil Fertility and Plant Nutrition

Which soil texture class is described as having the highest proportion of sand particles, giving it large pore spaces and rapid drainage?

  1. Clayey soil
  2. Sandy soil Correct answer.
  3. Loamy soil
  4. Silty soil

Explanation

Sandy soil is dominated by coarse sand particles, which create large pore spaces that let water drain away quickly and hold little moisture or nutrients. Clayey and silty soils have much finer particles with small pores that retain water strongly. Loamy soil is a balanced mixture rather than a sand-dominated class.

Question 22Soil Science, Soil Fertility and Plant Nutrition

In soil science, the term 'soil profile' refers to which of the following?

  1. The population of earthworms and microbes in the topsoil
  2. The vertical arrangement of horizons from the surface down to the parent material Correct answer.
  3. The total weight of soil contained in one hectare of plough layer
  4. The proportion of sand, silt and clay in a single sample

Explanation

A soil profile is a vertical cross-section of the soil showing the sequence of horizons (such as O, A, B and C) from the surface down to the underlying parent material. Each horizon differs in colour, texture and composition. The other options describe separate soil properties rather than the vertical horizon sequence.

Question 23Soil Science, Soil Fertility and Plant Nutrition

Which soil microorganism group is chiefly responsible for converting atmospheric nitrogen into plant-available forms in the root nodules of legumes?

  1. Rhizobium bacteria Correct answer.
  2. Penicillium fungi
  3. Nitrosomonas bacteria
  4. Actinomycetes

Explanation

Rhizobium bacteria live symbiotically in root nodules of legumes and fix atmospheric nitrogen into ammonia that the plant can use. Nitrosomonas oxidises ammonium to nitrite in nitrification rather than fixing free nitrogen. Penicillium is a fungus and actinomycetes are decomposers, neither being the legume nodule nitrogen fixer.

Question 24Soil Science, Soil Fertility and Plant Nutrition

Which of the following is classified as a macronutrient that plants require in relatively large amounts?

  1. Boron
  2. Potassium Correct answer.
  3. Molybdenum
  4. Zinc

Explanation

Potassium is one of the primary macronutrients, taken up by crops in large quantities and needed for enzyme activation, water regulation and grain filling. Zinc, boron and molybdenum are micronutrients required only in very small amounts, though they are still essential.

Question 25Soil Science, Soil Fertility and Plant Nutrition

Which soil property is measured by a pH meter reading of the soil-water suspension?

  1. Soil organic carbon content
  2. Soil bulk density
  3. Soil reaction, indicating acidity or alkalinity Correct answer.
  4. Soil water-holding capacity

Explanation

Soil pH measures soil reaction, that is, whether the soil is acidic, neutral or alkaline, based on hydrogen ion activity in the soil solution. Bulk density measures mass per volume, water-holding capacity measures moisture retention, and organic carbon is measured by combustion or wet oxidation. pH is not a measure of any of these.

Question 26Soil Science, Soil Fertility and Plant Nutrition

A farmer notices that water stands on the field for many hours after rain and the soil feels sticky when wet and hard when dry. Which soil texture is most likely responsible?

  1. Sandy soil
  2. Clayey soil Correct answer.
  3. Loamy sand
  4. Coarse gravelly soil

Explanation

Clayey soil has very fine particles and tiny pore spaces, so it holds water strongly, drains slowly and becomes sticky when wet and hard on drying. Sandy and gravelly soils have large pores and drain rapidly, so water does not stand. Loamy sand also drains too freely to cause prolonged standing water.

Question 27Soil Science, Soil Fertility and Plant Nutrition

Which practice is most directly aimed at conserving soil moisture in a rainfed crop field?

  1. Burning crop residues after harvest
  2. Deep ploughing to expose subsoil
  3. Mulching the soil surface with crop residues Correct answer.
  4. Removing all vegetation from the field borders

Explanation

Mulching covers the soil surface with crop residues, reducing evaporation, moderating soil temperature and conserving moisture in rainfed fields. Deep ploughing exposes moist subsoil and increases evaporation, burning residues destroys organic matter, and removing vegetation increases exposure and erosion risk.

Question 28Soil Science, Soil Fertility and Plant Nutrition

Which process converts ammonium nitrogen in soil into nitrate nitrogen under aerobic conditions?

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

Explanation

Nitrification is the aerobic microbial oxidation of ammonium to nitrite and then to nitrate, carried out by Nitrosomonas and Nitrobacter. Denitrification converts nitrate to nitrogen gas under anaerobic conditions, ammonification releases ammonium from organic matter, and nitrogen fixation converts atmospheric nitrogen into combined forms.

Question 29Soil Science, Soil Fertility and Plant Nutrition

A soil test shows pH 5.0 and the crop to be grown is sensitive to acidity. Which amendment is most appropriate to raise the pH toward neutrality?

  1. Application of ammonium sulphate
  2. Application of gypsum
  3. Application of elemental sulphur
  4. Application of agricultural lime Correct answer.

Explanation

Agricultural lime (calcium carbonate) neutralises soil acidity and raises pH toward neutral, which suits acid-sensitive crops. Gypsum adds calcium and sulphur without raising pH much, elemental sulphur and ammonium sulphate both acidify the soil further, so they would worsen the problem.

Question 30Soil Science, Soil Fertility and Plant Nutrition

Which fertiliser material is the principal source of phosphorus supplied to crops?

  1. Ammonium sulphate
  2. Muriate of potash
  3. Single superphosphate Correct answer.
  4. Urea

Explanation

Single superphosphate supplies phosphorus as available phosphate along with calcium and sulphur, making it a standard phosphatic fertiliser. Urea and ammonium sulphate are nitrogenous fertilisers, and muriate of potash supplies potassium, so none of these is a phosphorus source.

Question 31Soil Science, Soil Fertility and Plant Nutrition

A grower applies 100 kg of urea (46 per cent N) to one hectare. Approximately how much nitrogen is supplied?

  1. 100 kg N
  2. 23 kg N
  3. 4.6 kg N
  4. 46 kg N Correct answer.

Explanation

Nitrogen supplied equals the quantity of fertiliser multiplied by its nitrogen percentage, so 100 kg urea times 0.46 gives 46 kg N per hectare. The other figures either treat the whole weight as nitrogen, halve it, or misplace the decimal point.

Question 32Soil Science, Soil Fertility and Plant Nutrition

Which nutrient deficiency in a crop typically appears first as interveinal chlorosis on older leaves because the nutrient is mobile within the plant?

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

Explanation

Magnesium is mobile in the plant, so when it is deficient the plant moves it from older leaves to growing points, causing interveinal chlorosis on older leaves first. Calcium, boron and iron are immobile, so their deficiency symptoms appear first on young leaves and growing tips.

Question 33Soil Science, Soil Fertility and Plant Nutrition

Green manuring with a leguminous crop improves soil fertility mainly through which mechanism?

  1. Permanent removal of soil potassium reserves
  2. Direct neutralisation of soil acidity by root exudates
  3. Addition of organic matter and biologically fixed nitrogen when the crop is incorporated Correct answer.
  4. Increase of soil bulk density through root compaction

Explanation

A leguminous green manure crop fixes atmospheric nitrogen symbiotically and, when ploughed in, adds nitrogen-rich organic matter that improves fertility and structure. It does not neutralise acidity, it adds rather than removes nutrients, and it generally lowers rather than raises bulk density.

Question 34Soil Science, Soil Fertility and Plant Nutrition

Which soil erosion type is characterised by the removal of a thin uniform layer of topsoil by raindrop splash and sheet flow?

  1. Gully erosion
  2. Wind erosion
  3. Sheet erosion Correct answer.
  4. Rill erosion

Explanation

Sheet erosion removes a relatively uniform thin layer of topsoil across the surface by raindrop splash and unchannelled sheet flow. Rill and gully erosion cut distinct channels, and wind erosion is driven by wind rather than water flow.

Question 35Soil Science, Soil Fertility and Plant Nutrition

In a soil test report, a cation exchange capacity value indicates which of the following?

  1. The volume of water held at field capacity
  2. The soil's capacity to hold and exchange positively charged nutrient ions Correct answer.
  3. The total quantity of anions leached below the root zone
  4. The rate at which organic matter decomposes

Explanation

Cation exchange capacity measures the number of negatively charged exchange sites on clay and organic matter that hold positively charged ions such as calcium, magnesium and potassium for plant uptake. It is not a measure of anion leaching, decomposition rate or water content.

Question 36Soil Science, Soil Fertility and Plant Nutrition

Why is incorporation of well-decomposed farmyard manure preferred over applying fresh manure shortly before sowing?

  1. Fresh manure raises soil pH to harmful levels immediately
  2. Fresh manure contains no plant nutrients at all
  3. Well-decomposed manure has stable nutrients and does not cause temporary nitrogen immobilisation or heat damage to seedlings Correct answer.
  4. Well-decomposed manure is always free of weed seeds while fresh manure is sterile

Explanation

Well-decomposed farmyard manure has already undergone microbial breakdown, so its nutrients are more stable and it does not trigger strong nitrogen immobilisation or heating near germinating seed. Fresh manure is still decomposing and can immobilise nitrogen and injure seedlings. Fresh manure does contain nutrients and is not sterile.

Question 37Soil Science, Soil Fertility and Plant Nutrition

Which irrigation scheduling approach best matches water supply to crop water demand in a canal command area?

  1. Irrigating a fixed volume daily regardless of crop stage
  2. Irrigating only after plants show permanent wilting
  3. Irrigating at critical growth stages based on soil moisture and crop water requirement Correct answer.
  4. Irrigating continuously whenever canal water is available

Explanation

Scheduling irrigation around critical growth stages using soil moisture status and crop water requirement delivers water when the crop needs it most and uses canal supply efficiently. Continuous irrigation wastes water, irrigating only after permanent wilting causes yield loss, and a fixed daily volume ignores changing crop demand.

Question 38Soil Science, Soil Fertility and Plant Nutrition

Which combination of soil conditions most favours denitrification losses from applied nitrate fertiliser?

  1. Strongly acidic, well-aerated loam with low moisture
  2. Well-drained, aerated sandy soil with low organic matter
  3. Dry, cracked soil with high oxygen levels
  4. Waterlogged, poorly aerated soil with abundant organic matter Correct answer.

Explanation

Denitrification is carried out by anaerobic bacteria that convert nitrate to nitrogen gases when oxygen is scarce. Waterlogged, poorly aerated soil rich in organic matter provides the anaerobic conditions and energy source these bacteria need. Well-drained, dry or strongly aerated soils favour aerobic processes and retain nitrate better.

Question 39Soil Science, Soil Fertility and Plant Nutrition

A soil analysis reports a very wide carbon-to-nitrogen ratio of about 60:1 after incorporation of mature cereal straw. What is the most likely short-term consequence for the following crop?

  1. Immediate luxury consumption of nitrogen by the crop
  2. Permanent loss of soil cation exchange capacity
  3. Temporary nitrogen immobilisation and possible nitrogen deficiency in young plants Correct answer.
  4. Rapid increase in available soil phosphorus

Explanation

Material with a wide carbon-to-nitrogen ratio, such as mature straw, gives decomposing microbes abundant carbon relative to nitrogen, so they draw on soil nitrate and immobilise it temporarily. Young plants may then show nitrogen deficiency until decomposition balances. It does not cause luxury nitrogen uptake, boost phosphorus, or permanently destroy exchange capacity.

Question 40Soil Science, Soil Fertility and Plant Nutrition

Which statement best explains why heavy, continuous cereal cropping without legumes or nitrogen fertiliser gradually reduces soil nitrogen availability?

  1. Cereal crops convert nitrate into atmospheric nitrogen in their leaves
  2. Cereal roots actively destroy soil clay minerals that hold nitrogen
  3. Nitrogen is destroyed by sunlight falling on bare soil between crops
  4. Harvested grain removes nitrogen faster than biological fixation and mineralisation can replenish it Correct answer.

Explanation

Each harvested cereal crop exports nitrogen in the grain, while the field has no legume to fix atmospheric nitrogen and only limited organic matter to mineralise. The nitrogen balance therefore becomes negative over successive crops. Cereal roots do not destroy clay minerals, crops do not fix nitrogen back into the air, and sunlight does not destroy soil nitrogen.

Question 41Soil Science, Soil Fertility and Plant Nutrition

A field shows patchy crop growth with poor nodulation on a legume. Which diagnostic step is most appropriate before deciding on a corrective input?

  1. Apply a broad-spectrum fungicide to the whole field immediately
  2. Apply nitrogen fertiliser heavily to force nodulation
  3. Test soil pH and check whether the correct Rhizobium inoculant was used, since acidity and wrong strain both impair nodulation Correct answer.
  4. Increase irrigation depth without checking soil moisture

Explanation

Poor legume nodulation can result from soil acidity, which suppresses Rhizobium survival, or from absence of a compatible effective strain in the inoculant. Testing pH and checking inoculant suitability directs the corrective action. Fungicide, extra irrigation or heavy nitrogen would not address the cause and heavy nitrogen can even suppress nodulation.

Question 42Soil Science, Soil Fertility and Plant Nutrition

In a long-term fertility trial, a soil receiving continuous ammonium-based fertiliser becomes progressively more acidic. Which explanation best accounts for this acidification?

  1. Acidification results from increased phosphorus fixation by iron oxides
  2. Nitrification of ammonium releases hydrogen ions, and crop uptake of nitrate leaves excess cations removed, acidifying the soil Correct answer.
  3. Crop removal of potassium is the direct cause of the pH fall
  4. Ammonium fertiliser adds free hydrochloric acid directly to the soil

Explanation

When ammonium is nitrified, hydrogen ions are released into the soil solution, and when the crop takes up nitrate while leaving excess cations behind, the soil becomes more acidic. Ammonium fertilisers do not add free hydrochloric acid. Phosphorus fixation and potassium removal do not directly drive the pH decline described.

Question 43Soil Science, Soil Fertility and Plant Nutrition

Which reasoning correctly links soil texture to irrigation management for a sandy loam compared with a clay loam?

  1. Clay loam drains faster than sandy loam and therefore needs more frequent irrigation
  2. Both soils require identical irrigation intervals because texture does not affect water retention
  3. Sandy loam holds less water and needs smaller, more frequent irrigations, while clay loam holds more water and can take larger, less frequent applications Correct answer.
  4. Sandy loam holds more water and should be irrigated less frequently than clay loam

Explanation

Sandy loam has larger pores and lower water-holding capacity, so water percolates quickly and smaller, more frequent irrigations suit it. Clay loam retains more water and can accept larger, less frequent applications. Texture strongly affects retention, and clay loam drains more slowly than sandy loam, not faster.

Question 44Soil Science, Soil Fertility and Plant Nutrition

A grower wants to reduce phosphorus fixation in an acidic red soil before applying phosphatic fertiliser. Which strategy is most sound?

  1. Apply more elemental sulphur to lower pH further before phosphate application
  2. Apply phosphatic fertiliser only to the subsoil at depth
  3. Flood the field permanently to convert all iron to the ferrous form
  4. Apply lime to raise pH toward the range where iron and aluminium fixation is reduced, then incorporate phosphate Correct answer.

Explanation

In acidic red soils, soluble phosphate is fixed by iron and aluminium, reducing its availability. Liming to a less acidic pH reduces this fixation so applied phosphate remains more available. Adding sulphur would acidify further and worsen fixation, permanent flooding is impractical and creates other problems, and placing phosphate deep in the subsoil does not solve fixation.

Question 45Crop Improvement, Seed Technology and Varietal Selection

In the seed production chain, which generation is produced directly from breeder seed under the supervision of the originating plant breeder?

  1. Truthful labelled seed
  2. Foundation seed
  3. Nucleus seed Correct answer.
  4. Certified seed

Explanation

Nucleus seed is the initial small quantity of seed produced under the direct supervision of the plant breeder and is used to multiply foundation seed. It represents the highest genetic purity stage in the chain. Foundation seed is the next step, produced from nucleus or breeder seed.

Question 46Crop Improvement, Seed Technology and Varietal Selection

A farmer wants to test whether a new paddy variety is genuinely higher yielding than the local variety before adopting it widely. Which practice best serves this purpose?

  1. Purchase certified seed of the new variety and sow it on the whole field
  2. Ask neighbouring farmers which variety they prefer
  3. Conduct a replicated varietal trial on the farm over two seasons Correct answer.
  4. Compare yields of the two varieties from memory of last year's harvest

Explanation

A replicated field trial over more than one season controls soil variation and seasonal effects, allowing a reliable comparison of varietal performance. Single-season or unreplicated observations can be confounded by environment. This is the basis of varietal recommendation.

Question 47Crop Improvement, Seed Technology and Varietal Selection

Which of the following is the standard method used for testing the germination percentage of a seed lot in a seed testing laboratory?

  1. Weighing 100 seeds on an analytical balance
  2. Soaking seeds in water and measuring their swelling
  3. Placing seeds on moist filter paper or sand under controlled temperature and counting normal seedlings Correct answer.
  4. Counting the number of seeds that float in salt solution

Explanation

Germination testing in a seed laboratory involves placing a known number of seeds on a moist substrate such as filter paper or sand under controlled temperature and light, then counting normal seedlings after a specified period. This gives the germination percentage of the lot. Weight, swelling or floating are not valid germination tests.

Question 48Crop Improvement, Seed Technology and Varietal Selection

In crop improvement, the term 'variety' as used in the Indian Seeds Act refers to which of the following?

  1. A group of plants that can be distinguished by a specific character and is genetically uniform and stable Correct answer.
  2. A mixture of seeds of two or more crops
  3. Any seed lot that has been cleaned and graded
  4. Seed produced by any farmer for personal use

Explanation

A variety, as defined for seed certification and registration, is a group of plants distinguishable by a specific character, uniform and stable in that character. This definition underpins variety identification and release. Cleaned seed or mixtures do not meet this genetic definition.

Question 49Crop Improvement, Seed Technology and Varietal Selection

Which of the following is a self-pollinated crop in which pureline selection is most appropriate?

  1. Castor
  2. Maize
  3. Pearl millet
  4. Rice Correct answer.

Explanation

Rice is a predominantly self-pollinated crop, so pureline selection from single plants is effective because the selected plants breed true. Maize, pearl millet and castor are cross-pollinated and need different breeding methods. Pureline selection is suited to self-pollinated crops.

Question 50Crop Improvement, Seed Technology and Varietal Selection

During seed certification, which of the following is checked as a field standard for a certified seed crop?

  1. Seed coat colour of the harvested produce
  2. Moisture content of the harvested seed
  3. Weight of 1000 grains of the harvested produce
  4. Isolation distance from other varieties of the same crop Correct answer.

Explanation

Isolation distance is a field standard checked during field inspection to prevent cross-pollination or contamination between seed crops of the same species. Moisture content and grain weight are seed quality parameters checked after harvest. Field standards address the growing crop.