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Haryana BSEH Senior Secondary NSQF Agriculture study materials
Haryana BSEH Senior Secondary NSQF Agriculture study resources

Haryana BSEH Senior Secondary NSQF Agriculture practice questions

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Question 1Agronomy and Crop Production

Which crop is a kharif season crop in Haryana, normally sown with the onset of the south-west monsoon?

  1. Wheat
  2. Cotton Correct answer.
  3. Mustard
  4. Gram

Explanation

Kharif crops are sown with the arrival of monsoon rains in June-July and harvested in autumn. Cotton is a typical kharif crop of Haryana's semi-arid tracts, whereas wheat, mustard and gram are grown in the rabi season.

Question 2Agronomy and Crop Production

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

  1. The total quantity of seed sown per hectare in a season
  2. The number of crops grown on the same field in a year expressed as a percentage of the net sown area Correct answer.
  3. The ratio of grain yield to total biological yield
  4. The proportion of the cropped area that is irrigated

Explanation

Cropping intensity measures how many times a field is cropped in a year, calculated as gross cropped area divided by net sown area, multiplied by 100. Higher intensity means the same land is used for more than one crop per year.

Question 3Agronomy and Crop Production

Which soil texture class generally holds the highest amount of plant-available water per unit depth among the following?

  1. Coarse gravelly sand
  2. Gravel
  3. Loam Correct answer.
  4. Coarse sand

Explanation

Loam combines adequate silt and clay with sand, giving good pore-size distribution and high available water capacity. Coarse sands and gravels drain rapidly and retain little water in the root zone.

Question 4Agronomy and Crop Production

A farmer wants to sow wheat in Haryana after a paddy harvest. Which practice best helps in timely wheat sowing after late paddy harvesting?

  1. Flooding the field for two weeks before ploughing
  2. Deep ploughing to bury all crop residues
  3. Broadcasting seed on unlevelled, cloddy soil
  4. Zero-till drilling of wheat into the standing stubble without burning Correct answer.

Explanation

Zero-till drilling allows wheat to be sown directly into paddy residue immediately after harvest, conserving moisture and avoiding the delay caused by residue burning and repeated tillage. This is a key conservation agriculture practice in the rice-wheat system.

Question 5Agronomy and Crop Production

Which of the following is a leguminous pulse crop commonly grown in Haryana during the rabi season?

  1. Sunflower
  2. Sugarcane
  3. Pearl millet (bajra)
  4. Chickpea (gram) Correct answer.

Explanation

Chickpea, locally called gram, is a rabi pulse that fixes atmospheric nitrogen through rhizobia and fits well into rotations. It is a major pulse crop of Haryana's rainfed and irrigated lands.

Question 6Agronomy and Crop Production

Seed rate for a crop is best defined as which of the following?

  1. The total weight of grain harvested per hectare
  2. The quantity of viable seed sown per unit area to achieve the desired plant population Correct answer.
  3. The depth at which seed is placed in the soil
  4. The number of irrigation events applied during the season

Explanation

Seed rate is the weight or number of seeds sown per hectare, adjusted for germination percentage and seed size so that the target plant stand is achieved. It is distinct from yield, irrigation and sowing depth.

Question 7Agronomy and Crop Production

Which irrigation method is generally most suitable for a row crop like maize grown on a field with limited water supply?

  1. Furrow irrigation along the crop rows Correct answer.
  2. Uncontrolled border flooding
  3. Basin flooding of the entire field
  4. Continuous overhead sprinkling day and night

Explanation

Furrow irrigation guides water along the crop rows, wetting the root zone while reducing evaporation losses from the whole surface. It suits row crops and uses water more efficiently than flooding the entire field.

Question 8Agronomy and Crop Production

In Haryana, which practice is recommended to control the parasitic weed striga in sorghum fields?

  1. Sowing sorghum repeatedly on the same plot year after year
  2. Growing resistant or tolerant sorghum varieties and rotating with non-host crops Correct answer.
  3. Increasing nitrogen fertilizer heavily in the same field
  4. Flood irrigating the field continuously for the whole season

Explanation

Striga is a root parasite whose seeds persist in soil, so host resistance combined with rotation to non-host crops reduces the soil seed bank and infection. Continuous sorghum cropping and heavy nitrogen do not eliminate the parasite.

Question 9Agronomy and Crop Production

Which of the following is the primary purpose of applying farmyard manure to a field before sowing a cereal crop?

  1. To increase soil pH sharply within one week
  2. To sterilize the soil against all pathogens
  3. To supply organic matter and improve soil physical and biological properties Correct answer.
  4. To act as a quick-acting nitrogen top dressing during tillering

Explanation

Farmyard manure is a bulky organic source that adds organic carbon, improves aggregation, water retention and microbial activity. It releases nutrients slowly and is not a substitute for a rapid top dressing or a soil sterilant.

Question 10Agronomy and Crop Production

A field has a soil test value of 180 kg available nitrogen per hectare. Which interpretation is most appropriate for a cereal crop?

  1. The level indicates a deficiency of phosphorus
  2. The level is low, so nitrogen fertilizer is needed to meet the crop requirement Correct answer.
  3. The level shows the soil is saline
  4. The level is very high, so no nitrogen is needed at all

Explanation

Available nitrogen around 180 kg/ha is generally rated low for cereals, so fertilizer nitrogen must supplement soil supply to reach the crop's requirement. Soil test values for nitrogen do not indicate phosphorus status or salinity.

Question 11Agronomy and Crop Production

Which of the following best explains why legumes are included in a crop rotation with cereals?

  1. They deplete soil nitrogen faster than cereals
  2. They fix atmospheric nitrogen symbiotically and add residual nitrogen to the soil Correct answer.
  3. They eliminate the need for any irrigation
  4. They prevent all weeds from germinating

Explanation

Legumes form symbiotic associations with rhizobia that fix atmospheric nitrogen, part of which remains in residues and benefits the following cereal. They do not eliminate irrigation or weed problems, and they do not deplete nitrogen faster than cereals.

Question 12Agronomy and Crop Production

What is the main agronomic advantage of transplanting paddy seedlings into a puddled field rather than direct dry seeding?

  1. Better weed suppression and easier water management in the puddled soil Correct answer.
  2. Guaranteed higher yield under all moisture conditions
  3. Elimination of all insect pests
  4. Complete elimination of the need for fertilizer

Explanation

Puddling destroys soil structure and creates a reduced, waterlogged root zone that suppresses many weeds while making water management easier. It does not guarantee higher yield in every situation, nor does it remove fertilizer or pest needs.

Question 13Agronomy and Crop Production

In wheat, the critical stage for irrigation that most affects grain yield is which of the following?

  1. Crown root initiation stage Correct answer.
  2. Post-harvest drying stage
  3. Late dough stage
  4. Harvest stage

Explanation

Crown root initiation, about 20-25 days after sowing, is when the crown roots develop and the plant sets its yield potential; moisture stress at this stage sharply reduces yield. Other critical stages include tillering and grain filling, but the dough and harvest stages are too late to correct stress.

Question 14Agronomy and Crop Production

Which of the following is the most appropriate measure to reduce nitrate leaching in a sandy loam field under intensive cereal cropping?

  1. Increasing irrigation frequency without changing nitrogen timing
  2. Applying the entire nitrogen dose well before the monsoon
  3. Split nitrogen application to match crop demand and avoid heavy pre-monsoon doses Correct answer.
  4. Burning crop residues before sowing

Explanation

Splitting nitrogen into doses timed to crop uptake reduces the amount of nitrate present when drainage occurs, especially in sandy loams with low water and nutrient retention. Heavy pre-monsoon doses are most vulnerable to leaching.

Question 15Agronomy and Crop Production

A farmer observes that his mustard crop is infested with aphids during the flowering stage. Which integrated pest management approach is most appropriate as a first step?

  1. Apply only fungicides to the field
  2. Monitor the pest population and conserve natural enemies before deciding on a chemical spray Correct answer.
  3. Uproot and burn the entire crop immediately
  4. Spray the most toxic insecticide repeatedly without scouting

Explanation

Integrated pest management begins with monitoring and conserving natural enemies such as ladybird beetles and parasitoids, and chemicals are used only when the pest crosses the economic threshold. Blind repeated spraying or destroying the crop is not justified.

Question 16Agronomy and Crop Production

Which of the following describes the correct sequence for raising a nursery of vegetable seedlings before transplanting?

  1. Sow seed deep in flooded basins and keep them submerged
  2. Transplant seedlings immediately after germination without hardening
  3. Prepare raised beds, sow treated seed, water lightly, and harden seedlings before transplanting Correct answer.
  4. Store seed in water for a week before sowing

Explanation

Raised beds improve drainage and aeration, treated seed reduces disease, light watering avoids damping off, and hardening before transplanting improves seedling survival in the field. Submerging seed or transplanting unhardened seedlings reduces establishment.

Question 17Agronomy and Crop Production

What is the main reason for practising crop residue mulching in a rainfed field in southern Haryana?

  1. To reduce evaporation and conserve soil moisture for the crop Correct answer.
  2. To attract more insect pests to the field
  3. To increase soil temperature to very high levels
  4. To eliminate the need for any fertilizer

Explanation

A residue mulch shades the soil surface, lowering evaporation and conserving moisture, which is critical in rainfed areas. It moderates rather than raises soil temperature excessively and does not replace fertilizer.

Question 18Agronomy and Crop Production

Which of the following is the correct agronomic meaning of 'land preparation' in crop production?

  1. The grading and packing of produce for market
  2. The application of nitrogen fertilizer after sowing
  3. The harvesting and threshing of the mature crop
  4. Tillage operations that create a suitable seedbed for germination and root growth Correct answer.

Explanation

Land preparation involves ploughing, harrowing and levelling to produce a seedbed with adequate tilth, aeration and moisture for germination and root penetration. Fertilizer application, harvesting and post-harvest handling are separate operations.

Question 19Agronomy and Crop Production

A farmer in Haryana wants to grow a short-duration catch crop between the harvest of early potato and the sowing of wheat. Which crop choice best fits this niche?

  1. A full-season cotton crop
  2. A long-duration sugarcane crop
  3. A perennial fruit tree
  4. A short-duration leafy vegetable or fodder crop Correct answer.

Explanation

A catch crop must occupy the field briefly without delaying the next main crop, so short-duration leafy vegetables or fodder fit well. Long-duration crops such as sugarcane, cotton or perennial trees would overlap and delay wheat sowing.

Question 20Agronomy and Crop Production

Which of the following statements about the effect of soil pH on nutrient availability is most accurate?

  1. Soil pH has no influence on nutrient availability
  2. Most nutrients are optimally available near pH 6.5, while extreme acidity or alkalinity reduces availability Correct answer.
  3. Nutrient availability is highest at pH 3.0
  4. Nutrient availability is highest at pH 10.0

Explanation

Near pH 6.5 most essential nutrients remain soluble and available while toxic levels of aluminium and manganese are low. Strong acidity fixes phosphorus and releases toxic aluminium, while strong alkalinity reduces availability of micronutrients such as iron and zinc.

Question 21Agronomy and Crop Production

Which of the following is the correct interpretation of a 'critical period of crop-weed competition'?

  1. The growth stage during which weeds must be controlled to prevent the greatest yield loss Correct answer.
  2. The stage when weeds are most beneficial to the crop
  3. The period after harvest when weeds are irrelevant
  4. The stage when only hand weeding is allowed by law

Explanation

The critical period is the interval in the crop's life when weed competition most reduces yield, so control must be timed to it. Weeds are never beneficial to the crop, and no law restricts control to hand weeding.

Question 22Agronomy and Crop Production

A farmer applies 120 kg N, 60 kg P2O5 and 40 kg K2O per hectare to wheat. Which statement correctly describes this as a fertilizer recommendation?

  1. It is the seed rate for wheat
  2. It specifies the exact weight of urea, DAP and muriate of potash to be applied
  3. It is the total quantity of farmyard manure to be applied
  4. It is a graded fertilizer dose expressed in terms of nutrients, not in terms of fertilizer material weight Correct answer.

Explanation

Fertilizer recommendations are expressed as kilograms of nutrients (N, P2O5, K2O) per hectare; the farmer must convert these to fertilizer material weights using the nutrient content of each fertilizer. The doses given are nutrient-based, not material weights or manure quantities.

Question 23Agronomy and Crop Production

In a rice-wheat rotation, continuous puddling for rice followed by conventional wheat sowing leads to which soil problem over years?

  1. Complete elimination of all soil-borne pathogens
  2. Permanent increase in soil porosity
  3. Increased organic carbon content in the subsoil
  4. Subsurface compaction and deterioration of soil structure that impedes wheat root growth Correct answer.

Explanation

Repeated puddling destroys aggregates and creates a compacted layer below the plough depth, restricting water infiltration and wheat root penetration. It does not increase subsoil organic carbon or porosity, nor does it eliminate pathogens.

Question 24Agronomy and Crop Production

A grower wants to compare the water productivity of two irrigation schedules for wheat. Which measure is the most appropriate indicator?

  1. Total hours spent irrigating
  2. Number of labourers employed for irrigation
  3. Grain yield per unit of water applied (kg per hectare per millimetre) Correct answer.
  4. Total number of irrigations applied

Explanation

Water productivity relates output to water input, so grain yield per unit of water applied allows a valid comparison of schedules. Counting irrigations, hours or labourers describes inputs but not the efficiency of converting water into grain.

Question 25Agronomy and Crop Production

Which of the following best explains why a legume-cereal intercropping system such as pigeonpea with sorghum can give a yield advantage over sole cropping?

  1. Complementary resource use in time and space plus nitrogen transfer from the legume Correct answer.
  2. Elimination of all pests by the intercrop
  3. Identical root depths causing maximum competition
  4. Complete shading of the legume by the cereal

Explanation

Intercropping can exploit complementary canopy and root niches so that the combined land equivalent ratio exceeds one, and the legume may transfer some fixed nitrogen to the cereal. Identical root depths and complete shading would increase competition rather than give an advantage.

Question 26Agronomy and Crop Production

In a crop production plan for Haryana, a farmer is advised to follow a 'multiple cropping sequence'. Which of the following best describes this practice?

  1. Growing two or more crops on the same field in a single agricultural year in a planned order Correct answer.
  2. Growing only one long-duration crop each year to conserve soil moisture
  3. Growing several crops together in the same season without any row arrangement
  4. Growing the same crop repeatedly on the same field year after year

Explanation

Multiple cropping is the intensification of cropping in time and space, and a multiple cropping sequence means raising two or more crops in a planned order on the same field within one year. This raises cropping intensity and total returns per hectare compared with a single annual crop.

Question 27Agronomy and Crop Production

A farmer in the Karnal area wants to sow wheat at the optimum time. Which agronomic reason best justifies timely sowing of wheat in Haryana?

  1. Early sowing always increases vegetative growth without any risk of frost damage
  2. Sowing date has no effect on yield as long as the recommended seed rate is used
  3. Late sowing shifts grain filling into rising temperatures, which shortens the grain-filling period and lowers yield Correct answer.
  4. Late sowing increases the number of effective tillers and so compensates for lost time

Explanation

In wheat, delayed sowing pushes the reproductive and grain-filling phases into hotter weather, so the crop matures faster and grain weight falls. Timely sowing allows the crop to complete tillering and grain filling under cooler, more favourable temperatures.

Question 28Agronomy and Crop Production

A grower raises a nursery of paddy and wants healthy, vigorous seedlings for transplanting. Which practice is most appropriate for the nursery bed?

  1. Withhold all irrigation after sowing so that the seedlings develop deep roots
  2. Apply a light irrigation schedule and thin the seedlings so that each gets adequate space and light Correct answer.
  3. Sow the seed densely so that maximum seedlings are obtained from a small bed area
  4. Keep the nursery bed continuously submerged under deep water from sowing to uprooting

Explanation

A good paddy nursery needs adequate moisture but also light and space so seedlings develop strong stems and healthy roots. Light, frequent irrigation with proper spacing produces vigorous seedlings that establish well after transplanting.

Question 29Agronomy and Crop Production

A farmer applies a nitrogen fertilizer to a standing crop and then irrigates heavily the same day. Which management change would most improve nitrogen use efficiency?

  1. Apply the fertilizer in split doses and irrigate lightly to avoid deep percolation Correct answer.
  2. Broadcast the fertilizer on the dry surface and delay irrigation by a week
  3. Increase the dose of urea to compensate for the expected loss
  4. Mix the fertilizer with the seed at sowing time instead of applying it later

Explanation

Splitting nitrogen into doses matched to crop demand, and irrigating lightly so water does not move below the root zone, reduces leaching and volatilization losses. This raises the proportion of applied nitrogen taken up by the crop.

Question 30Agronomy and Crop Production

A farmer has two fields, one with a sandy loam and one with a heavy clay soil, and plans to irrigate both with the same volume of water. Which statement best explains the expected difference in irrigation performance?

  1. The clay soil will drain freely, so its plant-available water will be lower than that of the sandy loam
  2. Both soils will hold the same plant-available water because the applied volume is identical
  3. The sandy loam has lower water-holding capacity, so it will need lighter, more frequent irrigations than the clay Correct answer.
  4. The clay soil will accept water faster, so it needs a shorter irrigation interval than the sandy loam

Explanation

Sandy loam holds less plant-available water per unit depth than clay because of its coarser texture and lower porosity for retention. For the same applied depth, the sandy loam therefore exhausts its stored water sooner and requires lighter, more frequent irrigation.

Question 31Soil Science and Soil Health Management

Which soil texture class is considered the most suitable for most agricultural crops because it has a balanced proportion of sand, silt, and clay?

  1. Sandy soil
  2. Loam Correct answer.
  3. Gravelly soil
  4. Clay soil

Explanation

Loam holds a balanced mixture of sand, silt, and clay, so it combines good drainage and aeration with adequate water-holding capacity and nutrient retention. This balance makes it workable for a wide range of crops and irrigation practices.

Question 32Soil Science and Soil Health Management

A farmer's field soil feels smooth and floury when rubbed between the fingers and holds almost no shape when squeezed moist. Which particle size fraction dominates this soil?

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

Explanation

Silt particles are intermediate in size and give a smooth, floury or silky feel when rubbed, with little cohesion when moist. Sand feels gritty and clay feels sticky and can be moulded into a ribbon.

Question 33Soil Science and Soil Health Management

Which soil structure type is generally most favourable for root growth and water movement in agricultural topsoil?

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

Explanation

Granular structure consists of small, rounded aggregates that create a good balance of pore space for air, water, and roots. Platy and massive structures restrict water movement, while columnar structure is associated with sodic soils.

Question 34Soil Science and Soil Health Management

A soil sample has a pH of 5.2. Which management practice is most directly appropriate to correct this condition for a sensitive crop?

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

Explanation

A pH of 5.2 indicates strong acidity, and applying agricultural lime (calcium carbonate) raises pH by neutralizing soil acidity. Elemental sulphur and ammonium sulphate acidify soils further, while gypsum mainly supplies calcium and improves sodic soils without raising pH much.

Question 35Soil Science and Soil Health Management

Which practice is the most effective long-term measure for maintaining soil organic matter in a rainfed crop rotation?

  1. Burning crop residues after harvest
  2. Removing all crop residues for fodder
  3. Deep ploughing every season
  4. Adding well-decomposed farmyard manure and green manure Correct answer.

Explanation

Organic matter is built and maintained by adding carbon-rich materials such as farmyard manure, compost, and green manure crops. Residue burning and complete residue removal deplete the organic carbon pool.

Question 36Soil Science and Soil Health Management

In a soil test report, the term 'available nitrogen' usually refers to nitrogen extracted by which type of reagent?

  1. Alkaline potassium permanganate Correct answer.
  2. Sodium bicarbonate
  3. Neutral ammonium acetate
  4. Dilute sulphuric acid

Explanation

Available (alkaline permanganate-oxidizable) nitrogen is estimated by distilling the soil with alkaline potassium permanganate, which releases readily oxidizable organic nitrogen. Neutral ammonium acetate is used for exchangeable cations and sodium bicarbonate for available phosphorus.

Question 37Soil Science and Soil Health Management

A soil is classified as saline when which combination of properties is observed?

  1. Low electrical conductivity and high sodium adsorption ratio
  2. High electrical conductivity and high exchangeable sodium percentage
  3. High electrical conductivity, low exchangeable sodium percentage, and near-neutral pH Correct answer.
  4. Low electrical conductivity and high pH

Explanation

Saline soils are characterized by high soluble salt content, measured as high electrical conductivity, while the exchangeable sodium percentage remains low and pH is generally near neutral. Sodic soils, by contrast, have high exchangeable sodium and often high pH.

Question 38Soil Science and Soil Health Management

Which amendment is recommended for reclaiming a sodic soil with high exchangeable sodium?

  1. Superphosphate
  2. Urea
  3. Gypsum Correct answer.
  4. Muriate of potash

Explanation

Gypsum supplies calcium, which replaces sodium on the exchange complex, and the sodium is then leached away with good-quality irrigation water. This is the standard chemical amendment for sodic soil reclamation.

Question 39Soil Science and Soil Health Management

Which water-holding category is used in soil moisture terminology for water held between field capacity and permanent wilting point?

  1. Gravitational water
  2. Runoff water
  3. Capillary water Correct answer.
  4. Hygroscopic water

Explanation

Capillary water is retained in the soil pores between field capacity and permanent wilting point and is the main form available to plants. Gravitational water drains away, and hygroscopic water is held too tightly for plant uptake.

Question 40Soil Science and Soil Health Management

A field has a soil moisture content at field capacity of 28 percent and at permanent wilting point of 14 percent on a weight basis. If the bulk density is 1.4 g/cm3 and the root zone depth is 30 cm, what is the approximate available water capacity in mm?

  1. 59 mm Correct answer.
  2. 29 mm
  3. 118 mm
  4. 14 mm

Explanation

Available water on a weight basis is 28 minus 14, or 14 percent. Multiplying by bulk density (1.4) gives 19.6 percent by volume, and over 300 mm of depth this equals about 59 mm of available water.

Question 41Soil Science and Soil Health Management

Which microorganism group is chiefly responsible for converting atmospheric nitrogen into plant-available forms in symbiotic association with legume roots?

  1. Pseudomonas
  2. Azotobacter
  3. Rhizobium Correct answer.
  4. Nitrosomonas

Explanation

Rhizobium bacteria form nodules on legume roots and fix atmospheric nitrogen symbiotically, supplying nitrogen to the host plant. Azotobacter is free-living, while Nitrosomonas oxidizes ammonia in nitrification.

Question 42Soil Science and Soil Health Management

Which nutrient is most commonly deficient in Indian soils and is supplied by urea?

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

Explanation

Nitrogen is the most widely deficient nutrient in cultivated soils, and urea is the most commonly used nitrogen fertilizer. Zinc, boron, and molybdenum are micronutrients with narrower deficiency ranges.

Question 43Soil Science and Soil Health Management

In the context of fertilizer recommendations, what does the term 'STCR' refer to?

  1. Seed Treatment Crop Record
  2. Soil Test Crop Response Correct answer.
  3. Soil Texture Classification Report
  4. Standard Tillage Crop Rotation

Explanation

STCR stands for Soil Test Crop Response, an approach that uses soil test values and crop response data to prescribe fertilizer doses for a target yield. It improves fertilizer efficiency compared with blanket recommendations.

Question 44Soil Science and Soil Health Management

Which practice best reduces nitrate leaching from a sandy field receiving high nitrogen fertilizer?

  1. Flood irrigating immediately after fertilizer application
  2. Using only ammonium sulphate
  3. Splitting nitrogen application to match crop demand Correct answer.
  4. Applying the full nitrogen dose at sowing

Explanation

Splitting nitrogen applications synchronizes supply with crop uptake, reducing the amount of nitrate left in the soil to leach. Applying all nitrogen at sowing or heavy irrigation after fertilization increases leaching losses.

Question 45Soil Science and Soil Health Management

Which soil erosion type involves the removal of a thin uniform layer of topsoil by raindrop impact 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 shallow overland flow. Rills and gullies are concentrated channels, while wind erosion is driven by wind rather than water.

Question 46Soil Science and Soil Health Management

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

  1. Removing all vegetation from the slope
  2. Deep ploughing down the slope
  3. Contour bunding with vegetative barriers Correct answer.
  4. Burning residues before the monsoon

Explanation

Contour bunding and vegetative barriers slow runoff, trap sediment, and reduce slope length, which together cut soil loss on steep land. Ploughing down the slope, removing vegetation, and burning residues all accelerate erosion.

Question 47Soil Science and Soil Health Management

Which soil order in the USDA Soil Taxonomy is characterized by thick, dark, organic-rich surface horizons formed under grassland vegetation?

  1. Oxisols
  2. Aridisols
  3. Histosols
  4. Mollisols Correct answer.

Explanation

Mollisols have a thick, dark, base-rich surface horizon formed under grassland and are among the most fertile agricultural soils. Aridisols are dry soils, Oxisols are highly weathered, and Histosols are organic soils.

Question 48Soil Science and Soil Health Management

Which factor most directly determines the cation exchange capacity contributed by the clay fraction of a soil?

  1. Colour of the clay
  2. Type of clay mineral present Correct answer.
  3. Amount of gravel in the soil
  4. Depth of the water table

Explanation

Different clay minerals carry different surface charges, so the type of clay mineral strongly determines cation exchange capacity. Smectite clays have high CEC, while kaolinite has low CEC. Colour, water table depth, and gravel content do not directly determine CEC.

Question 49Soil Science and Soil Health Management

Which soil microorganism is chiefly responsible for the conversion of ammonia to nitrite during nitrification?

  1. Rhizobium
  2. Nitrosomonas Correct answer.
  3. Azospirillum
  4. Nitrobacter

Explanation

Nitrosomonas oxidizes ammonia to nitrite, and Nitrobacter then converts nitrite to nitrate in the second step of nitrification. Rhizobium and Azospirillum are nitrogen-fixing bacteria, not nitrifiers.

Question 50Soil Science and Soil Health Management

A soil test shows a high phosphorus value but the crop shows phosphorus deficiency symptoms. Which explanation is most plausible?

  1. Low soil temperature only
  2. Too much organic matter in the soil
  3. Excess nitrogen in the soil
  4. High soil pH or calcium carbonate fixing phosphorus Correct answer.

Explanation

In calcareous or high-pH soils, phosphorus is fixed as calcium phosphates and becomes unavailable even when total soil phosphorus is high. This mismatch between soil test value and plant uptake is a classic indicator of fixation.