- Which of the following is a primary nutrient for plants?
a) Iron
b) Manganese
c) Nitrogen
d) Zinc
Answer: c) Nitrogen
Explanation: Primary nutrients are those required by plants in relatively large quantities: Nitrogen (N), Phosphorus (P), and Potassium (K). They are also called macronutrients. Iron, manganese, and zinc are micronutrients needed in smaller amounts.
- The element that is a constituent of chlorophyll molecule is:
a) Nitrogen
b) Phosphorus
c) Potassium
d) Calcium
Answer: a) Nitrogen
Explanation: Nitrogen is an essential constituent of the chlorophyll molecule, proteins, nucleic acids, and many other plant compounds. Chlorophyll contains nitrogen in its porphyrin ring structure. Magnesium is also a component of chlorophyll.
- Which nutrient is essential for energy transfer reactions in plants (ATP formation)?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Sulfur
Answer: b) Phosphorus
Explanation: Phosphorus is a component of ATP (adenosine triphosphate), the energy currency of cells. It’s involved in all energy transfer reactions, photosynthesis, respiration, and genetic material (DNA, RNA).
- The deficiency symptom of nitrogen appears first on:
a) Young leaves
b) Old leaves
c) Stem
d) Flowers
Answer: b) Old leaves
Explanation: Nitrogen is a mobile element in plants, meaning it can be translocated from older tissues to younger growing points when deficient. Therefore, deficiency symptoms (chlorosis – yellowing) appear first on older leaves, starting from leaf tip along midrib.
- DAP (Diammonium phosphate) fertilizer contains:
a) 18% N and 46% P2O5
b) 46% N and 18% P2O5
c) 20% N and 20% P2O5
d) 12% N and 32% P2O5
Answer: a) 18% N and 46% P2O5
*Explanation: DAP (Diammonium phosphate) contains 18% Nitrogen and 46% Phosphorus (as P2O5). It’s a high-analysis, water-soluble fertilizer suitable for many crops and soils. The other common phosphate fertilizer is SSP (Single Superphosphate) with 16% P2O5.*
- Which of the following is a potassium fertilizer?
a) Urea
b) MOP (Muriate of Potash)
c) SSP
d) Ammonium sulfate
Answer: b) MOP (Muriate of Potash)
Explanation: Muriate of Potash (KCl) contains 60% K2O and is the most common potassium fertilizer. Urea (46% N) is nitrogenous, SSP (16% P2O5) is phosphatic, and ammonium sulfate (21% N, 24% S) is nitrogenous with sulfur.
- The process by which plants absorb nutrients in ionic form through roots is called:
a) Photosynthesis
b) Transpiration
c) Nutrient uptake
d) Respiration
Answer: c) Nutrient uptake
*Explanation: Nutrient uptake is the process by which plants absorb mineral nutrients from the soil solution through their root systems. Nutrients are absorbed mainly as ions (cations like NH4+, K+, Ca2+ and anions like NO3-, H2PO4-, SO42-).*
- Zinc deficiency in plants causes:
a) Interveinal chlorosis in young leaves
b) Purple discoloration of leaves
c) Necrosis of leaf tips
d) Rolling of leaves
Answer: a) Interveinal chlorosis in young leaves
Explanation: Zinc deficiency causes interveinal chlorosis (yellowing between veins) in young leaves because zinc is relatively immobile in plants. Other symptoms include small leaves (little leaf), rosetting, and shortened internodes.
- Which of the following is a micronutrient?
a) Calcium
b) Magnesium
c) Sulfur
d) Boron
Answer: d) Boron
*Explanation: Boron is a micronutrient required in small quantities (0.5-2 ppm in plant tissue). Calcium, magnesium, and sulfur are secondary nutrients (required in moderate amounts) – not micronutrients but also not primary nutrients (NPK).*
- The critical limit for available nitrogen in soil is generally considered as:
a) 100 kg/ha
b) 280 kg/ha
c) 500 kg/ha
d) 1000 kg/ha
Answer: b) 280 kg/ha
*Explanation: The critical limit for available nitrogen (alkaline permanganate method) in soil is generally considered as 280 kg/ha. Soils with available N below this are classified as low, 280-560 kg/ha as medium, and above 560 kg/ha as high in nitrogen.*
- Which method of fertilizer application involves placing fertilizer in bands on one or both sides of the seed?
a) Broadcasting
b) Drilling
c) Side dressing
d) Foliar application
Answer: c) Side dressing
Explanation: Side dressing involves placing fertilizer in bands or strips on one or both sides of the plant rows, usually after crop emergence. This ensures nutrients are available in the root zone and reduces fixation losses, especially for phosphorus.
- Urea should not be applied to soil surface without incorporation because:
a) It is too soluble
b) It can be lost as ammonia gas through volatilization
c) It damages soil structure
d) It attracts pests
Answer: b) It can be lost as ammonia gas through volatilization
*Explanation: Urea applied to soil surface without incorporation is hydrolyzed by urease enzyme to ammonium carbonate, which decomposes to release ammonia gas (volatilization loss). Losses can be 20-40% if not incorporated within 2-3 days of application.*
- The nutrient that helps in protein synthesis and imparts dark green color to leaves is:
a) Phosphorus
b) Potassium
c) Nitrogen
d) Calcium
Answer: c) Nitrogen
Explanation: Nitrogen is a key component of amino acids, which are building blocks of proteins. It also imparts dark green color to leaves as it’s a component of chlorophyll. Adequate nitrogen gives plants healthy, dark green foliage.
- Which of the following is a slow-release nitrogen fertilizer?
a) Urea
b) Ammonium sulfate
c) Neem-coated urea
d) Calcium ammonium nitrate
Answer: c) Neem-coated urea
Explanation: Neem-coated urea is a slow-release fertilizer where urea granules are coated with neem oil or neem cake. The coating inhibits nitrification (conversion of ammonium to nitrate) and urease activity, reducing nitrogen losses and making nitrogen available over longer period.
- The phenomenon where plants show deficiency symptoms of an element even though it is present in sufficient quantity in soil is called:
a) Nutrient deficiency
b) Nutrient toxicity
c) Induced deficiency
d) Nutrient fixation
Answer: c) Induced deficiency
Explanation: Induced deficiency occurs when an element is present in adequate amounts in soil but is unavailable to plants due to antagonistic effects of other elements or unfavorable soil conditions (pH, waterlogging). Example: Iron deficiency in calcareous soils.
- Which nutrient deficiency causes “heart rot” in sugarbeet and “brown heart” in turnips?
a) Zinc deficiency
b) Iron deficiency
c) Boron deficiency
d) Manganese deficiency
Answer: c) Boron deficiency
Explanation: Boron deficiency causes various disorders: heart rot in sugarbeet and turnips, brown heart in rutabaga, hollow stem in cauliflower, fruit cracking in celery, and poor fruit set in many crops. Boron is essential for cell wall formation and membrane integrity.
- The 4R nutrient stewardship concept in fertilizer management refers to:
a) Right source, Right rate, Right time, Right place
b) Right rain, Right soil, Right crop, Right season
c) Right research, Right recommendations, Right results, Right returns
d) None of the above
Answer: a) Right source, Right rate, Right time, Right place
Explanation: The 4R nutrient stewardship is a globally accepted approach for sustainable fertilizer management: using the Right source of nutrient, at the Right rate, at the Right time, and in the Right place to optimize crop yield, minimize environmental impact, and maximize economic returns.
- The C:N ratio of FYM (Farm Yard Manure) is generally:
a) 5:1
b) 10:1
c) 20:1
d) 40:1
Answer: c) 20:1
*Explanation: Well-decomposed FYM typically has a C:N ratio around 20:1. Fresh manure may have wider ratio (30-40:1). The ideal C:N ratio for decomposition is 30:1, but FYM with 20:1 decomposes readily and releases nutrients without causing nitrogen immobilization.*
- Which of the following is a complete fertilizer?
a) Urea
b) SSP
c) 10-26-26
d) MOP
Answer: c) 10-26-26
*Explanation: A complete fertilizer contains all three primary nutrients (N, P2O5, K2O). 10-26-26 contains 10% N, 26% P2O5, and 26% K2O. Urea has only N, SSP only P, and MOP only K – these are incomplete or straight fertilizers.*
- The nutrient primarily responsible for root development and early plant growth is:
a) Nitrogen
b) Phosphorus
c) Potassium
d) Sulfur
Answer: b) Phosphorus
Explanation: Phosphorus is essential for root development, cell division, and early plant growth. It promotes vigorous root systems, which helps plants establish quickly and access water and nutrients from soil. P deficiency results in stunted growth and purple discoloration.
- Biofertilizers for nitrogen fixation in non-leguminous crops like wheat include:
a) Rhizobium
b) Azotobacter
c) Azolla
d) Frankia
Answer: b) Azotobacter
Explanation: Azotobacter is a free-living nitrogen-fixing bacterium used as biofertilizer for non-leguminous crops like wheat, maize, and vegetables. Rhizobium is specific to legumes, Azolla (with Anabaena) is for rice, and Frankia nodulates non-legume trees.
- The nutrient that imparts disease resistance, stalk strength, and improves quality of fruits and grains is:
a) Nitrogen
b) Phosphorus
c) Potassium
d) Magnesium
Answer: c) Potassium
Explanation: Potassium (K) is known as the “quality nutrient.” It strengthens stalks and stems (preventing lodging), activates over 60 enzymes, regulates stomatal opening, improves disease resistance, and enhances quality parameters like size, color, taste, and shelf life of produce.
- Which of the following is an example of phosphatic fertilizer?
a) CAN (Calcium Ammonium Nitrate)
b) AS (Ammonium Sulfate)
c) SSP (Single Superphosphate)
d) SOP (Sulfate of Potash)
Answer: c) SSP (Single Superphosphate)
*Explanation: SSP contains 16% P2O5 and is a phosphatic fertilizer. CAN (26% N) and AS (21% N) are nitrogenous fertilizers, while SOP (50% K2O, 18% S) is a potassium fertilizer preferred for chloride-sensitive crops.*
- Foliar application of fertilizers is most effective when:
a) Soil conditions limit nutrient uptake
b) Quick response is needed
c) Micronutrients are to be applied in small quantities
d) All of the above
Answer: d) All of the above
*Explanation: Foliar fertilization is effective when soil conditions (high pH, salinity, cold temperature) limit nutrient uptake, when quick correction of deficiency is needed (rapid response within 2-5 days), and for micronutrients needed in small quantities where soil application may lead to fixation.*
- The amount of fertilizer containing 46% N required to supply 100 kg N per hectare is approximately:
a) 100 kg
b) 150 kg
c) 217 kg
d) 300 kg
Answer: c) 217 kg
*Explanation: If fertilizer contains 46% N, then to supply 100 kg N: 100 ÷ 0.46 = 217.4 kg. Therefore, approximately 217 kg of fertilizer (like urea) is needed per hectare to provide 100 kg of nitrogen.*
Agronomy MCQs – Set 6: Cropping Systems and Farming Methods (25 Questions)
- Growing two or more crops simultaneously on the same land in a mixed stand without distinct row arrangement is called:
a) Intercropping
b) Mixed cropping
c) Relay cropping
d) Sequence cropping
Answer: b) Mixed cropping
Explanation: Mixed cropping involves growing two or more crops simultaneously on the same land without any distinct row arrangement. This traditional practice is common in rainfed areas as an insurance against crop failure. The crops are mixed randomly.
- In intercropping, the objective is to:
a) Maximize yield of both crops
b) Achieve yield advantage through complementarity
c) Grow crops without any competition
d) Eliminate the need for fertilizers
Answer: b) Achieve yield advantage through complementarity
Explanation: Intercropping aims to achieve yield advantage by growing crops that complement each other in resource use (light, water, nutrients), reduce pest incidence, and provide overall greater productivity and stability than sole cropping.
- The ratio used to compare the total land area needed under sole cropping to yield the same produce as intercropping is:
a) Harvest index
b) Crop intensity index
c) Land Equivalent Ratio (LER)
d) Competition ratio
Answer: c) Land Equivalent Ratio (LER)
*Explanation: LER is the ratio of the area needed under sole cropping to produce the same yields as intercropping. LER > 1 indicates intercropping advantage (yield advantage), LER = 1 indicates no advantage, LER < 1 indicates disadvantage.*
- Relay cropping means:
a) All crops planted at the same time
b) Second crop planted after harvest of first
c) Second crop planted before harvest of first
d) Crops grown in different seasons
Answer: c) Second crop planted before harvest of first
Explanation: Relay cropping involves planting the second crop into the standing first crop before it is harvested. This allows better utilization of time, resources, and extends the growing season, especially in areas with short growing periods.
- Which of the following is an example of parallel multiple cropping?
a) Wheat followed by rice
b) Potato + Radish
c) Maize + Cowpea (1:1 row ratio)
d) Pigeonpea intercropped with soybean
Answer: b) Potato + Radish
Explanation: Parallel multiple cropping involves growing two or more crops together without distinct row arrangement, often with different maturity times. Potato + radish is an example where radish matures early and is harvested, leaving potato to grow further.
- The system where trees and agricultural crops are grown together is called:
a) Silviculture
b) Agrisilviculture
c) Horticulture
d) Aquaculture
Answer: b) Agrisilviculture
Explanation: Agrisilviculture is a component of agroforestry where agricultural crops are grown together with trees/shrubs. The trees provide additional products (timber, fuel, fodder) while crops give annual returns. It optimizes land use and provides ecological benefits.
- Growing a single crop on a farm year after year is called:
a) Crop rotation
b) Monocropping
c) Multiple cropping
d) Lay farming
Answer: b) Monocropping
Explanation: Monocropping (monoculture) is the agricultural practice of growing the same single crop on the same land year after year. This can lead to soil fertility depletion, buildup of pests and diseases, and increased risk from market or weather fluctuations.
- The practice of growing crops in the space between rows of trees or shrubs is called:
a) Alley cropping
b) Strip cropping
c) Contour cropping
d) Terrace cropping
Answer: a) Alley cropping
Explanation: Alley cropping involves growing agricultural crops in the alleys or spaces between rows of trees or shrubs (usually nitrogen-fixing species). The trees are pruned periodically to provide green manure and reduce competition with crops.
- In multiple cropping, cropping intensity is calculated as:
a) (Gross cropped area / Net sown area) × 100
b) (Net sown area / Gross cropped area) × 100
c) (Total cropped area / Fallow area) × 100
d) (Irrigated area / Total cropped area) × 100
Answer: a) (Gross cropped area / Net sown area) × 100
Explanation: Cropping intensity measures how intensively the land is used for crop production in a year. If gross cropped area (total area cropped including multiple crops) is 200 hectares and net sown area (physical area) is 100 hectares, cropping intensity is 200%.
- Which of the following cropping systems is most suitable for irrigated areas with high rainfall?
a) Mono-cropping
b) Multiple cropping
c) Shifting cultivation
d) Dry farming
Answer: b) Multiple cropping
*Explanation: Multiple cropping is most suitable for irrigated areas and regions with adequate rainfall where water is available throughout the year. It allows growing 2-3 crops annually, maximizing land productivity and farmer income.*
- The most common intercropping system in rainfed areas of India is:
a) Rice-wheat
b) Sorghum + Pigeonpea
c) Potato + Onion
d) Sugarcane + Wheat
Answer: b) Sorghum + Pigeonpea
*Explanation: Sorghum (cereal) + pigeonpea (legume) is the most common intercropping system in rainfed areas of central and southern India. Sorghum is harvested early (100-120 days), leaving pigeonpea (180-200 days) to utilize residual moisture.*
- The main advantage of intercropping legumes with cereals is:
a) Nitrogen fixation by legumes benefits cereals
b) Better weed control
c) Reduced pest incidence
d) All of the above
Answer: d) All of the above
Explanation: Legume-cereal intercropping provides multiple benefits: legumes fix atmospheric nitrogen benefiting associated cereal (direct transfer through root exudates or from residue decomposition), provide better ground cover reducing weeds, and break pest cycles.
- Paired row planting system where wider row spacing is alternated with narrower rows is called:
a) Skip row planting
b) Paired row planting
c) Bed planting
d) Ridge planting
Answer: b) Paired row planting
Explanation: Paired row planting involves growing two rows close together (paired) followed by a wider space, then another pair. This facilitates intercropping, irrigation, and intercultural operations. It’s common in maize, cotton, and sugarcane.
- The system where crops are grown on raised beds separated by furrows for irrigation/drainage is called:
a) Ridge and furrow system
b) Broad bed and furrow system
c) Contour system
d) Flat bed system
Answer: b) Broad bed and furrow system
*Explanation: Broad bed and furrow (BBF) system involves making broad raised beds (1.2-1.5 m wide) separated by furrows. Crops are grown on beds, and furrows serve for irrigation and drainage. It’s excellent for vertisols in rainfed areas (developed by ICRISAT).*
- Sequential cropping means:
a) Growing two or more crops in sequence on the same land in a year
b) Growing crops simultaneously
c) Growing crops with trees
d) Growing the same crop repeatedly
Answer: a) Growing two or more crops in sequence on the same land in a year
Explanation: Sequential cropping involves growing two or more crops in succession on the same land in a year, where the second crop is planted after harvesting the first. Examples include rice-wheat, maize-potato, etc.
- The concept of “evergreen revolution” in agriculture emphasizes:
a) Only increasing food production
b) Sustainable productivity growth without ecological harm
c) Complete mechanization
d) Organic farming only
Answer: b) Sustainable productivity growth without ecological harm
Explanation: The evergreen revolution, a term coined by Dr. M.S. Swaminathan, emphasizes increasing agricultural productivity in a manner that is sustainable over time without causing ecological damage – improving productivity in perpetuity without ecological harm.
- Which of the following is NOT a principle of intercropping?
a) Choose crops with different maturity durations
b) Choose crops with similar rooting patterns
c) Choose crops with different growth habits
d) Choose crops with complementary resource use
Answer: b) Choose crops with similar rooting patterns
Explanation: Intercropping should pair crops with different rooting patterns (deep and shallow) to exploit different soil layers and reduce competition. Similar rooting patterns would compete for nutrients and water from the same zone.
- The total productivity per unit area and time in multiple cropping systems is measured by:
a) Yield per crop
b) Total biomass
c) Production efficiency
d) Harvest index
Answer: c) Production efficiency
Explanation: Production efficiency in multiple cropping measures output per unit area per unit time (kg/ha/day). This accounts for both yield and time taken, providing a better comparison between systems with different crop durations.
- Growing fodder crops in rotation with grain crops is beneficial because:
a) Fodder crops add organic matter
b) They break pest cycles
c) They provide animal feed and manure
d) All of the above
Answer: d) All of the above
Explanation: Fodder crops in rotation improve soil organic matter through root biomass, break pest/disease cycles, provide nutritious feed for livestock, and the manure from animals can be returned to fields, creating integrated crop-livestock farming systems.
- The system of growing rice on terraced fields on hill slopes is an example of:
a) Shifting cultivation
b) Contour farming
c) Terrace farming
d) Bench terracing
Answer: d) Bench terracing
Explanation: Bench terracing involves converting steep slopes into level steps or benches for crop cultivation, especially rice. It’s common in hilly areas of Northeast India, Himalayas, and other mountainous regions to control erosion and retain water.
- The main constraint in multiple cropping is:
a) Availability of improved varieties
b) Availability of water
c) Availability of labor
d) Availability of fertilizers
Answer: b) Availability of water
*Explanation: While all factors are important, the main constraint for multiple cropping (growing 2-3 crops annually) is adequate water availability throughout the year. Without sufficient irrigation or well-distributed rainfall, multiple cropping is not feasible.*
- Which of the following is a time dimension of cropping systems?
a) Intercropping
b) Mixed cropping
c) Crop rotation
d) Strip cropping
Answer: c) Crop rotation
Explanation: Cropping systems have both spatial and temporal dimensions. Crop rotation represents the temporal (time) dimension – the sequence of crops over years. Intercropping, mixed cropping, and strip cropping are spatial arrangements.
- Zero tillage is a practice of:
a) Plowing the field thoroughly
b) Sowing seeds without any prior tillage
c) Deep plowing once in 3 years
d) Minimum tillage with reduced operations
Answer: b) Sowing seeds without any prior tillage
Explanation: Zero tillage (no-till) involves sowing seeds directly into untilled soil with special planters that open a narrow slot for seed placement. It conserves soil moisture, reduces erosion, saves fuel and labor, and improves soil health through minimal disturbance.
- Conservation agriculture is based on three principles:
a) Tillage, fertilization, irrigation
b) Minimum soil disturbance, permanent soil cover, crop rotation
c) High inputs, high yields, high profits
d) Organic farming, biodynamics, natural farming
Answer: b) Minimum soil disturbance, permanent soil cover, crop rotation
Explanation: Conservation agriculture rests on three interlinked principles: (1) Minimum mechanical soil disturbance (no-till/reduced till), (2) Permanent organic soil cover (mulch/residues), and (3) Diversified crop rotations/associations.
- The main advantage of bed planting system is:
a) Better water management
b) Reduced compaction
c) Easy intercultural operations
d) All of the above
Answer: d) All of the above
Explanation: Bed planting (growing crops on raised beds) offers multiple advantages: irrigation water can be applied in furrows (saving 30-40% water), bed top remains uncompacted facilitating root growth, and intercultural operations (weeding, fertilizer application) are easier.
