1000 Most Important Agronomy MCQs with Explanation for ICAR JRF, NET, AFO & All Agriculture Exams
Integrated Farming System (IFS) refers to: a) Growing only one crop b) Integration of crop, livestock, fishery, poultry, etc. for synergistic resource use c) Monocropping d) Only organic farming
Answer: b) Integration of crop, livestock, fishery, poultry, etc. for synergistic resource use
Explanation: IFS combines various farm enterprises (crops, livestock, poultry, fishery, apiary, mushroom) where outputs of one become inputs for another. This ensures recycling of resources, risk diversification, higher income, and employment round the year.
The main advantage of IFS is: a) Increased dependence on external inputs b) Waste recycling and nutrient synergy c) Higher risk d) Seasonal employment
In IFS, “duck-cum-fish” integration is beneficial because: a) Ducks eat fish b) Ducks control weeds and pests in ponds, manure enriches water c) Fish eat ducks d) No interaction
Answer: b) Ducks control weeds and pests in ponds, manure enriches water
Explanation: In duck-fish integration, ducks in ponds control aquatic weeds and pests, their droppings fertilize the water (increasing fish food), and they get feed from pond organisms. This increases fish yield without external inputs.
The “Poultry-cum-fish” integration system utilizes: a) Poultry meat for fish b) Poultry droppings as pond fertilizer (increases fish productivity) c) Fish for poultry feed d) No interaction
Answer: b) Poultry droppings as pond fertilizer (increases fish productivity)
Explanation: Poultry droppings are rich in nitrogen and phosphorus, fertilizing fish ponds and promoting plankton growth (fish food). This increases fish yield while managing poultry waste. Poultry houses are often built over or near ponds.
“Vermicomposting” in IFS involves: a) Using earthworms to convert organic waste into nutrient-rich compost b) Growing vegetables c) Fish farming d) Poultry rearing
Answer: a) Using earthworms to convert organic waste into nutrient-rich compost
Explanation: Vermicomposting uses earthworms (Eisenia fetida) to decompose farm organic waste (crop residues, animal dung) into vermicompost – a high-quality organic manure rich in nutrients and beneficial microbes. It’s a key recycling component in IFS.
The “Rice-Fish” culture system is practiced in: a) Arid regions b) Waterlogged and low-lying areas c) Hilly areas d) Sandy soils
Answer: b) Waterlogged and low-lying areas
Explanation: Rice-fish culture integrates fish in flooded rice fields. Fish control weeds, pests, and algae; their movement aerates water; and manure fertilizes rice. Common in NE India, Kerala, and parts of SE Asia. Fish (carp, tilapia) are harvested along with rice.
The “Mushroom cultivation” in IFS utilizes: a) Fresh vegetables b) Agricultural wastes (paddy straw, wheat straw) as substrate c) Live plants d) Fish waste
Answer: b) Agricultural wastes (paddy straw, wheat straw) as substrate
Explanation: Mushroom cultivation uses agricultural residues (straw, sawdust) as growing substrate, converting waste into protein-rich food. Spent mushroom substrate can be used as manure. It provides additional income and employment.
“Apiculture” (bee-keeping) in IFS benefits crops through: a) Honey production only b) Pollination services (increased crop yields) c) Beeswax only d) Pest control
Answer: b) Pollination services (increased crop yields)
*Explanation: Bees provide pollination services that increase yields of many crops (sunflower, mustard, fruits, vegetables) by 20-30%. Honey and beeswax are additional products. Integrating apiculture enhances farm productivity and biodiversity.*
The “Goat-cum-crop” integration is common in: a) High rainfall areas b) Arid and semi-arid regions c) Cold deserts d) Coastal areas
Answer: b) Arid and semi-arid regions
Explanation: Goats are hardy animals suited to arid/semi-arid regions. They graze on scrub, weeds, and crop residues, providing meat, milk, and manure. Goat manure enriches soil for crop production. This integration is common in Rajasthan, Gujarat, and rainfed areas.
. The “dairy-cum-biogas” system in IFS involves: a) Using cow dung for biogas production b) Direct use of dung as fuel c) Burning crop residues d) Chemical fertilizers
Answer: a) Using cow dung for biogas production
Explanation: In dairy-cum-biogas system, cow dung is fed into biogas plants to produce methane (for cooking, lighting) and slurry (nutrient-rich manure for crops). This recycles waste, provides clean energy, and reduces dependence on external fuel and fertilizers.
“Azolla” cultivation in IFS is important as: a) Fish feed b) Green manure (nitrogen-rich) c) Poultry feed supplement d) All of the above
Answer: d) All of the above
Explanation: Azolla is a free-floating aquatic fern that fixes atmospheric nitrogen through symbiosis with Anabaena. It’s used as green manure in rice, protein-rich feed for poultry, pig, and fish, and as biofertilizer. It grows rapidly in shallow water.
The “Horticulture + Livestock + Fishery” integration is an example of: a) Monocropping b) Integrated Farming System c) Shifting cultivation d) Organic farming only
Answer: b) Integrated Farming System
Explanation: Combining horticulture (fruits, vegetables) with livestock (dairy, goat, poultry) and fishery (fish pond) on same farm is a classic IFS. Components complement each other – pond water irrigates crops, livestock manure fertilizes fish pond and crops, etc.
. “Boundary plantation” in IFS refers to: a) Planting crops in boundaries b) Planting trees/fodder on field boundaries for multiple benefits c) Fencing only d) No specific purpose
Answer: b) Planting trees/fodder on field boundaries for multiple benefits
Explanation: Boundary plantation involves planting trees (fodder, fruit, timber) on field bunds and boundaries. They provide additional products, act as windbreaks, reduce erosion, and don’t compete with main crops for space.
The main objective of IFS for small and marginal farmers is: a) Maximizing risk b) Ensuring year-round income and employment, reducing risk c) Dependence on single crop d) Purchasing all inputs from market
Answer: b) Ensuring year-round income and employment, reducing risk
Explanation: IFS diversifies farm enterprises, providing income and employment throughout the year. If one component fails (crop failure), others (livestock, poultry) sustain income. This reduces risk and improves livelihood security for small farmers.
The “Integrated Nutrient Management” (INM) in IFS combines: a) Only chemical fertilizers b) Organic manures, biofertilizers, and chemical fertilizers c) Only organic manures d) Only biofertilizers
Answer: b) Organic manures, biofertilizers, and chemical fertilizers
Explanation: INM integrates all nutrient sources – organic (FYM, compost, green manure), biological (biofertilizers), and inorganic (chemical fertilizers) in an optimal combination. This maintains soil health, improves nutrient use efficiency, and sustains productivity.
“Multitier cropping” in IFS involves: a) Growing crops of different heights together b) Growing same height crops c) Monocropping d) No interaction
Answer: a) Growing crops of different heights together
Explanation: Multitier cropping (multistoried) grows crops of different heights together – tall trees (coconut), medium (fruit trees), and short (vegetables, spices) in same area. It optimizes space, light, and resource use, common in homestead gardens of Kerala.
. The “homestead farming” in Kerala is a classic example of: a) Monocropping b) Integrated Farming System c) Shifting cultivation d) Plantation agriculture
Answer: b) Integrated Farming System
Explanation: Homestead farming in Kerala integrates coconut, pepper, banana, vegetables, spices, livestock, poultry, and fish pond in small holdings. It provides diverse produce, recycles waste, and ensures year-round food and income – an excellent IFS model.
“Biogas slurry” from IFS is valuable as: a) Fuel only b) Organic manure rich in nutrients c) Animal feed d) Pesticide
Answer: b) Organic manure rich in nutrients
Explanation: Biogas slurry (digested from biogas plant) is an excellent organic manure with higher available nutrients than raw dung. It contains N, P, K, and micronutrients in available forms and improves soil health when applied to crops.
The “crop-livestock” integration is beneficial because: a) Livestock provide manure for crops b) Crop residues feed livestock c) Both a and b – synergistic relationship d) No interaction
Answer: c) Both a and b – synergistic relationship
Explanation: Crop-livestock integration creates synergy – crop residues (straw, stover) feed livestock, livestock provide manure for crops, draught power for operations. This recycles nutrients, reduces external inputs, and sustains productivity.
“Sericulture” (silk farming) in IFS involves: a) Rearing silkworms on mulberry leaves b) Fish farming c) Poultry rearing d) Mushroom cultivation
Answer: a) Rearing silkworms on mulberry leaves
Explanation: Sericulture integrates mulberry cultivation (on field bunds, boundaries) with silkworm rearing. Mulberry leaves feed silkworms, producing silk cocoons. Waste from silkworms can be used as manure. It’s an additional income source.
. The “FPO” (Farmer Producer Organization) concept in IFS helps farmers with: a) Collective production, processing, and marketing b) Individual farming only c) Reducing cooperation d) Increasing input costs
Answer: a) Collective production, processing, and marketing
Explanation: FPOs are farmer collectives that aggregate produce, access inputs at lower cost, provide processing facilities, and market collectively for better prices. They strengthen farmers’ bargaining power and reduce transaction costs.
“Value addition” in IFS means: a) Selling raw produce only b) Processing farm products to increase their value (milk to paneer, fruits to jam) c) Adding fertilizers d) Increasing farm size
Answer: b) Processing farm products to increase their value (milk to paneer, fruits to jam)
Explanation: Value addition involves processing primary products into higher-value items – making pickles from vegetables, jam from fruits, paneer from milk, flour from grains. This increases income, reduces post-harvest losses, and creates employment.
. The “National Livestock Mission” in India focuses on: a) Crop production b) Sustainable livestock development c) Fisheries only d) Organic farming
Answer: b) Sustainable livestock development
*Explanation: National Livestock Mission (launched 2014-15) aims for sustainable livestock development through breed improvement, feed management, disease control, and livestock entrepreneurship. It complements IFS by strengthening the livestock component.*
The “Blue Revolution” in India is associated with: a) Crop production b) Fisheries and aquaculture c) Organic farming d) Dairy development
Answer: b) Fisheries and aquaculture
Explanation: Blue Revolution refers to the rapid growth of fisheries and aquaculture in India through technology, infrastructure, and policy support. It’s integrated with crop production in IFS through fish farming in ponds and rice-fish systems.
The most suitable IFS model for a 1-hectare small farm in rainfed condition would include: a) Only rice crop b) Only livestock c) Crops + livestock + poultry + composting + boundary plantation d) Only vegetables
Explanation: For small rainfed farms, IFS should integrate drought-tolerant crops, small ruminants (goat/sheep) or poultry (low investment), composting units, and boundary plantations for fodder/fruit. This diversifies income, recycles resources, and reduces risk.
. The “Grand Growth Period” (GGP) in sugarcane refers to: a) 0-60 days after planting b) 60-120 days after planting c) 120-270 days after planting d) 270-360 days after planting
Answer: c) 120-270 days after planting
*Explanation: The Grand Growth Period (GGP) in sugarcane occurs between 120-270 days after planting, characterized by rapid cane elongation, active tillering, and maximum biomass accumulation. This is the most critical phase for irrigation and nutrient management, as moisture stress during GGP can reduce yields by 40-50%.*
Which physiological disorder in rice is caused by excess iron toxicity? a) Khaira disease b) Bronzing c) Akiochi d) Straighthead
Answer: b) Bronzing
*Explanation: Bronzing in rice is caused by iron toxicity, common in acid sulfate soils and waterlogged conditions. Symptoms include small brown spots on lower leaves starting from tips, eventually covering entire leaves giving bronze appearance. It occurs when iron concentration exceeds 300-500 ppm in plant tissue.*
The critical limit of available zinc in soil for most crops is: a) 0.2 ppm b) 0.6 ppm c) 1.2 ppm d) 2.5 ppm
Answer: b) 0.6 ppm
*Explanation: The critical limit for available zinc (DTPA-extractable) in soil is 0.6 ppm. Soils with Zn below this are considered deficient. Zinc deficiency is widespread in Indian soils (about 50% soils deficient), causing yield losses in rice, wheat, maize, and pulses. Application of 25-50 kg ZnSO₄/ha corrects deficiency.*
Which weed is known to cause “Lathyrism” in humans when consumed? a) Parthenium hysterophorus b) Lathyrus sativus (Khesari) c) Argemone mexicana d) Datura stramonium
Answer: b) Lathyrus sativus (Khesari)
Explanation: Lathyrus sativus (Khesari dal) contains a neurotoxin called β-ODAP (β-N-oxalyl-L-α,β-diaminopropionic acid) which causes lathyrism – a paralytic disease characterized by irreversible spastic paraparesis when consumed in excess over long periods. The crop is, however, drought-tolerant and grown in rainfed areas.
. The “Hormone concept” of weed management utilizes: a) 2,4-D and other auxin-type herbicides b) Glyphosate only c) Paraquat only d) Atrazine only
Answer: a) 2,4-D and other auxin-type herbicides
*Explanation: The hormone concept refers to using synthetic auxins (2,4-D, MCPA, dicamba) that disrupt normal growth processes in broadleaf weeds. These herbicides mimic natural auxins (IAA), causing uncontrolled growth, epinasty, stem curling, and ultimately plant death. They are selective for broadleaf weeds in cereal crops.*
The “C4 plants” have higher water use efficiency because: a) They have Kranz anatomy b) They open stomata at night c) They have higher transpiration rate d) They lack bundle sheath cells
Answer: a) They have Kranz anatomy
*Explanation: C4 plants (maize, sugarcane, sorghum, pearl millet) have Kranz anatomy with two distinct photosynthetic cell types (mesophyll and bundle sheath cells). This concentrates CO₂ at the RuBisCO site, suppressing photorespiration and allowing higher photosynthetic efficiency with less water loss. Their water use efficiency is 2-3 times higher than C3 plants.*
. The “Vascular bundle arrangement” in monocot stem is: a) Conjoint, collateral and closed b) Conjoint, bicollateral c) Radial d) Concentric
Answer: a) Conjoint, collateral and closed
Explanation: Monocot stems have conjoint, collateral, and closed vascular bundles scattered throughout the ground tissue. “Conjoint” means xylem and phloem together, “collateral” means xylem and phloem on same radius with phloem outside, and “closed” means no cambium (secondary growth absent). Dicots have open vascular bundles with cambium.
. The “C/N ratio” of well-decomposed farm yard manure should be: a) 10:1 b) 20:1 c) 30:1 d) 40:1
Answer: b) 20:1
*Explanation: Well-decomposed FYM should have C:N ratio of 20:1 or less. Fresh manure has wider ratio (30-40:1). During decomposition, microorganisms use carbon as energy source and release CO₂, narrowing the ratio. FYM with C:N ratio below 20:1 mineralizes nitrogen rapidly, while wider ratios may cause temporary nitrogen immobilization.*
The “Tillage” operation that is done to create a seedbed after primary tillage is called: a) Primary tillage b) Secondary tillage c) Tertiary tillage d) Subsoiling
Answer: b) Secondary tillage
*Explanation: Secondary tillage follows primary tillage and aims to create a fine, firm seedbed for seed germination and plant establishment. Operations include harrowing, levelling, planking, and cultivating. It works on the top 10-15 cm soil, while primary tillage (ploughing) works deeper (15-30 cm).*
The “Sub-soiling” is done to: a) Create seedbed b) Break hardpan or compacted layers below plough depth c) Incorporate fertilizers d) Control weeds
Answer: b) Break hardpan or compacted layers below plough depth
*Explanation: Sub-soiling is a deep tillage operation (45-75 cm depth) that breaks hardpans, compacted layers, or plough soles without inverting soil. It improves water infiltration, root penetration, and drainage. It’s especially important in soils with restricted layers caused by repeated ploughing at same depth.*
. “Soil consistence” refers to: a) Soil color b) Soil texture c) Soil’s resistance to deformation and rupture d) Soil pH
Answer: c) Soil’s resistance to deformation and rupture
Explanation: Soil consistence describes the soil’s resistance to deformation or rupture at various moisture contents. Terms used: loose, soft, firm, hard when dry; loose, friable, firm when moist; sticky, plastic when wet. It affects tillage ease, root penetration, and trafficability.
The “Atterberg limits” are used to characterize: a) Soil texture b) Soil structure c) Soil consistency (plasticity) in fine-grained soils d) Soil color
Answer: c) Soil consistency (plasticity) in fine-grained soils
Explanation: Atterberg limits (liquid limit, plastic limit, shrinkage limit) define the moisture content ranges where soil exhibits different consistency states. They’re crucial for characterizing clayey soils, determining their engineering properties, and predicting behavior under varying moisture conditions.
. The “Bulk density” of an ideal agricultural soil should be less than: a) 1.0 g/cc b) 1.4 g/cc c) 1.6 g/cc d) 2.0 g/cc
Answer: c) 1.6 g/cc
*Explanation: For most agricultural soils, bulk density should be less than 1.6 g/cc. Values above 1.6 g/cc indicate compaction that restricts root growth, reduces aeration, and limits water infiltration. Ideal bulk density for plant growth is 1.2-1.4 g/cc. Sandy soils have higher BD than clayey soils.*
. “Guttation” in plants occurs when: a) Stomata are open b) Root pressure is high and transpiration is low c) Transpiration is high d) Soil is dry
Answer: b) Root pressure is high and transpiration is low
Explanation: Guttation is the exudation of water droplets from hydathodes (specialized pores) at leaf margins. It occurs when root pressure is high (warm, moist soil) and transpiration is low (high humidity, early morning). It’s common in grasses, strawberry, tomato, and Colocasia.
“Imbibition” is a phenomenon of: a) Water absorption by seeds through hydrophilic colloids b) Water loss through stomata c) Water movement through xylem d) Water condensation
Answer: a) Water absorption by seeds through hydrophilic colloids
Explanation: Imbibition is the adsorption of water by hydrophilic colloids (proteins, cellulose, starch) in seed coats and tissues. It’s the first step in seed germination, causing swelling and softening of seed coat, activating enzymes, and initiating metabolic processes. Imbibition pressure can be very high (up to 1000 atm).
. The “Donnan equilibrium” in plant nutrition refers to: a) Equal distribution of ions b) Unequal distribution of ions across membrane due to fixed charges c) Passive absorption only d) Active transport only
Answer: b) Unequal distribution of ions across membrane due to fixed charges
Explanation: Donnan equilibrium describes the unequal distribution of ions across a semi-permeable membrane due to presence of nondiffusible ions (fixed charges) on one side. In plants, cell walls have fixed negative charges that attract cations (Ca²⁺, Mg²⁺, K⁺) and influence ion uptake and distribution.
“Luxury consumption” of nutrients refers to: a) Plants consuming nutrients in excess of their metabolic needs b) Plants dying from excess nutrients c) Deficiency symptoms appearing d) No nutrient uptake
Answer: a) Plants consuming nutrients in excess of their metabolic needs
Explanation: Luxury consumption occurs when plants absorb nutrients in amounts exceeding their immediate metabolic requirements when nutrients are abundantly available. This is common with potassium in many crops. The excess is stored in tissues and can be utilized later when external supply is limited.
“Vant Hoff’s factor” in osmotic pressure calculation is represented by: a) i b) π c) Ψ d) R
Answer: a) i
*Explanation: Vant Hoff’s factor (i) accounts for the number of ions produced when a solute dissociates in solution. In osmotic pressure equation (π = iCRT), i = 1 for non-electrolytes (sucrose), i = 2 for NaCl (dissociates into Na⁺ and Cl⁻), i = 3 for CaCl₂. This affects soil water potential and plant water uptake.*
The “Energy flow” in ecosystem follows: a) Cyclic path b) Unidirectional path c) Random path d) Bidirectional path
Answer: b) Unidirectional path
Explanation: Energy flow in ecosystems is unidirectional – from sun → producers (plants) → consumers → decomposers. Energy is lost as heat at each trophic level (second law of thermodynamics). Unlike nutrients which cycle, energy flows through the system and cannot be recycled.
“Ecological succession” refers to: a) Seasonal changes in vegetation b) Changes in community composition over time in a given area c) Migration of species d) Daily fluctuations
Answer: b) Changes in community composition over time in a given area
Explanation: Ecological succession is the process of change in species composition of a community over time. Primary succession occurs on bare rocks (no soil initially), secondary succession on areas where vegetation was removed but soil exists. It proceeds from pioneer species to climax community.
. “Allelopathy” was first scientifically described by: a) Charles Darwin b) Hans Molisch (1937) c) Gregor Mendel d) Norman Borlaug
Answer: b) Hans Molisch (1937)
*Explanation: The term “allelopathy” was coined by Austrian scientist Hans Molisch in 1937, derived from Greek words “allelon” (mutual) and “pathos” (harm/suffering). It refers to the direct or indirect harmful or beneficial effects of one plant on another through release of chemical compounds.*
“Parthenium hysterophorus” control through biological method uses: a) Trichoderma b) Mexican beetle (Zygogramma bicolorata) c) Bacillus thuringiensis d) NPV
Answer: b) Mexican beetle (Zygogramma bicolorata)
Explanation: Zygogramma bicolorata (Mexican beetle) was introduced in India for biological control of Parthenium hysterophorus (Congress grass). Both adult beetles and larvae feed on Parthenium leaves, defoliating and suppressing the weed. It’s a successful classical biological control agent.
. The “critical stage” for weed competition in transplanted rice is: a) 0-15 days after transplanting b) 30-45 days after transplanting c) 60-75 days after transplanting d) 90-105 days after transplanting
Answer: b) 30-45 days after transplanting
*Explanation: The critical period of crop-weed competition in transplanted rice is 30-45 days after transplanting (DAT). During this period, weeds cause maximum yield loss (30-60%) if not controlled. Weed-free maintenance during this phase is essential. After canopy closure (45-50 DAT), weeds are suppressed by crop shade.*
“Stale seedbed technique” is most effective for controlling: a) Perennial weeds b) First flush of annual weeds from soil seed bank c) Parasitic weeds d) Aquatic weeds
Answer: b) First flush of annual weeds from soil seed bank
Explanation: Stale seedbed (false seedbed) technique involves preparing seedbed, irrigating to stimulate weed seed germination, destroying emerged weeds (by shallow tillage or non-selective herbicide), and then sowing crop. It effectively reduces the first flush of annual weeds from the soil seed bank.
“Solarization” for weed control is most effective when done during: a) Winter months (December-January) b) Summer months (May-June) c) Monsoon months (July-August) d) Any time of year
Answer: b) Summer months (May-June)
*Explanation: Solarization involves covering moist soil with transparent polythene for 4-6 weeks during hot summer months (May-June). Solar radiation heats soil to 45-55°C, killing weed seeds, pathogens, and nematodes. It’s most effective in areas with high temperatures and intense solar radiation.*
