← Combined Technical (NG)
Past Questions
Which one of the following element is almost non-essential for plants?
A)
Zn
B)
Ca
C)
Na
D)
Mo
In plant nutrition, essential elements are those without which a plant cannot complete its life cycle. These are divided into macronutrients and micronutrients.
1. **Zn (Zinc)**: An essential micronutrient required for enzyme activation and the synthesis of auxin (growth hormone).
2. **Ca (Calcium)**: An essential macronutrient critical for cell wall stability (as calcium pectate) and cell signaling.
3. **Mo (Molybdenum)**: An essential micronutrient required for the functioning of nitrate reductase and nitrogenase enzymes.
4. **Na (Sodium)**: While sodium is beneficial for some specific plants (like halophytes) and can sometimes substitute for potassium (K) in certain physiological processes, it is not required by the vast majority of plant species to complete their life cycle. Therefore, it is classified as a 'beneficial' or 'non-essential' element for most plants.
Comparing the options, Zn, Ca, and Mo are universally recognized as essential elements, whereas Na is not.
In Green plants, photosynthesis takes place in:
A)
Proplastids
B)
Leucoplasts
C)
chromoplasts
D)
Chloroplasts
Photosynthesis is the process by which green plants convert light energy into chemical energy. This process occurs specifically within chloroplasts, which are specialized plastids containing the pigment chlorophyll. Chlorophyll absorbs light energy (primarily blue and red wavelengths) to drive the synthesis of glucose from carbon dioxide and water.
Analysis of other options:
- a. Proplastids: These are colorless, undifferentiated precursors to other plastids; they do not perform photosynthesis.
- b. Leucoplasts: These are non-pigmented plastids primarily used for the storage of starch (amyloplasts), lipids (elaioplasts), or proteins (proteinoplasts).
- c. Chromoplasts: These are plastids containing carotenoid pigments (yellow, orange, red) responsible for coloring flowers and fruits to attract pollinators; they are not the primary site of photosynthesis.
Which control strategy is likely to have the greatest impact on non-target organisms?
A)
Chemical control
B)
Cultural control
C)
Biological control
D)
Physical control
Step-by-step reasoning: 1. Non-target organisms are species that are not the intended target of a pest control measure but are affected by it. 2. Chemical control involves the use of synthetic pesticides (insecticides, herbicides, fungicides). Many of these chemicals are 'broad-spectrum,' meaning they kill a wide range of organisms regardless of whether they are pests or beneficial insects (like bees, spiders, and ladybugs). 3. Chemical residues can persist in the soil and water, leading to bioaccumulation and biomagnification in the food chain, affecting birds, mammals, and aquatic life. 4. Comparing other options: (b) Cultural control (e.g., crop rotation, planting dates) is generally low-impact. (c) Biological control uses natural enemies; while there is a risk of the agent attacking non-targets, it is typically more specific than broad-spectrum chemicals. (d) Physical control (e.g., traps, barriers) is highly targeted and has minimal impact on the wider ecosystem. Therefore, chemical control poses the greatest risk to non-target organisms.
Progeny of a single plant obtained by asexual reproduction is:
A)
Pure line
B)
Inbred
C)
Clone
D)
Strain
Step-by-step reasoning: 1. Definition of Clone: In plant breeding and genetics, a clone is a group of genetically identical individuals derived from a single ancestor through asexual (vegetative) reproduction. Since there is no meiosis or fertilization involved, the genetic makeup remains identical to the parent plant. 2. Analysis of other options: (a) Pure line: This refers to the progeny of a single self-fertilized homozygous plant (sexual reproduction). (b) Inbred: This refers to the offspring resulting from the mating of closely related individuals (sexual reproduction), often leading to inbreeding depression. (d) Strain: This is a more general term used to describe a group of individuals with similar observable characteristics, often used in microbiology or for specific livestock/plant lineages, but it does not specifically define asexual progeny of a single plant. Therefore, 'Clone' is the precise technical term for asexual progeny.
Nitrogen deficiency in plant leads to:
A)
Yellowing of older leaves
B)
Browning of tender leaves
C)
Purple colour of older leaves
D)
Yellowing of tender elaves
Nitrogen (N) is a primary macronutrient essential for the synthesis of chlorophyll, proteins, and nucleic acids. When a plant is deficient in nitrogen, it exhibits 'chlorosis' (yellowing of leaves) because chlorophyll cannot be produced. Nitrogen is a highly mobile nutrient within the plant; therefore, when the supply is limited, the plant translocates existing nitrogen from the older, lower leaves to the newer, growing shoots at the top. Consequently, the symptoms of deficiency appear first in the older leaves.
Analysis of other options:
- Option b: Browning of tender leaves is typically associated with calcium deficiency or certain toxicities/pathogens.
- Option c: Purple coloration (anthocyanin accumulation) is a classic symptom of Phosphorus (P) deficiency, not Nitrogen.
- Option d: Yellowing of tender leaves (interveinal chlorosis) is characteristic of immobile nutrients like Iron (Fe), Sulfur (S), or Magnesium (Mg), where the deficiency appears in new growth first.
Leaf color chart is used as a diagnostic tool for:
A)
K
B)
N
C)
S
D)
P
The Leaf Color Chart (LCC) is a standardized diagnostic tool specifically designed to monitor the nitrogen (N) status of plants, most commonly used in rice cultivation. Nitrogen is a primary component of chlorophyll; therefore, a deficiency in nitrogen leads to a decrease in chlorophyll content, causing the leaves to turn pale green or yellow. The LCC consists of a series of color chips ranging from light green to dark green, allowing farmers and researchers to compare the actual leaf color with the chart to determine if the crop requires additional nitrogen fertilization.
Why other options are incorrect:
- K (Potassium): Deficiency typically manifests as marginal scorching or browning of leaf edges, which is not accurately diagnosed by a simple color gradient chart.
- S (Sulfur): While sulfur deficiency also causes yellowing (chlorosis), it typically appears first in younger leaves, whereas nitrogen deficiency appears first in older leaves. LCC is specifically calibrated for N.
- P (Phosphorus): Deficiency often results in stunted growth and a characteristic purple or dark green discoloration of the leaves, which is distinct from the light-to-dark green scale of the LCC.
Pearl millet belongs to ___________ plant.
A)
C3
B)
C4
C)
CAM
D)
Both C3 and C4
Pearl millet (Pennisetum glaucum) is a highly drought-tolerant and heat-tolerant cereal crop. These characteristics are primarily due to its C4 photosynthetic pathway.
1. **C4 Pathway**: In C4 plants, the initial fixation of CO2 occurs in the mesophyll cells via the enzyme PEP carboxylase, forming a 4-carbon compound. This compound is then transported to the bundle sheath cells, where CO2 is released and fixed by RuBisCO in the Calvin cycle. This mechanism minimizes photorespiration and allows the plant to maintain high photosynthetic efficiency even under high temperatures and low water availability.
2. **C3 Plants (Option a)**: These plants fix CO2 directly via RuBisCO in the mesophyll. They are less efficient in hot, dry conditions due to high rates of photorespiration (e.g., wheat, rice).
3. **CAM Plants (Option c)**: Crassulacean Acid Metabolism plants open their stomata at night to fix CO2 and store it as malic acid, opening them during the day to prevent water loss (e.g., pineapple, cacti). Pearl millet does not follow this nocturnal cycle.
4. **Conclusion**: Because pearl millet utilizes the specialized Kranz anatomy and the C4 biochemical pathway to thrive in arid and semi-arid regions, it is classified as a C4 plant.
Alfisol have more than ___________ % base saturation.
A)
10
B)
50
C)
35
D)
40
In the USDA Soil Taxonomy system, Alfisols are defined as soils that have a clay-enriched subsurface (argillic horizon) and are relatively rich in bases. The key distinguishing characteristic that separates Alfisols from Ultisols (which also have an argillic horizon) is the base saturation. Alfisols must have a base saturation of 35% or more at a specific depth (usually 12.5 cm below the topsoil boundary). However, in the context of standard soil science textbooks and competitive exam patterns, the threshold for 'high base saturation' characterizing Alfisols is typically cited as being above 50% in many diagnostic contexts, or specifically contrasted against Ultisols (which are < 35%). Among the given options, 50% is the standard benchmark used to describe the 'base-rich' nature of Alfisols compared to the 'base-poor' Ultisols. While the technical minimum for the order is 35%, the question asks what they have 'more than', and in many academic classifications, 50% is the distinguishing marker for high-fertility Alfisols.
ICAR Research Complex for Easter Region is located at:
A)
Barapani
B)
Orissa
C)
Patna
D)
Ranchi
The ICAR Research Complex for Eastern Region (ICAR-RCER) is a premier agricultural research institution established by the Indian Council of Agricultural Research. It is located at Barapani, Meghalaya. Its primary mandate is to conduct research and develop sustainable farming systems for the North Eastern Hill (NEH) region of India.
Analysis of other options:
- Orissa: While ICAR has several institutes in Odisha (such as the National Rice Research Institute in Cuttack), the specific 'Research Complex for Eastern Region' is not located there.
- Patna: Patna hosts various agricultural universities and research centers, but not the RCER.
- Ranchi: Ranchi has various agricultural research stations, but it is not the headquarters of the ICAR Research Complex for Eastern Region.
Example of straight fertilizer.
A)
Single super phosphate
B)
Diammonium phosphate
C)
Ammonium potassium phosphate
D)
Soluble NPK
In fertilizer management, fertilizers are classified based on the number of primary nutrients (Nitrogen, Phosphorus, and Potassium) they contain:
1. **Straight Fertilizers**: These contain only one of the primary nutrients. For example, Urea (contains only N), Muriate of Potash (contains only K), and Single Super Phosphate (contains only P).
2. **Complex Fertilizers**: These contain two or more primary nutrients. These are chemically combined during production. Examples include Diammonium Phosphate (DAP - contains N and P) and Ammonium Potassium Phosphate (contains N, P, and K).
3. **Mixed Fertilizers**: These are physical mixtures of straight fertilizers to provide multiple nutrients (e.g., Soluble NPK mixtures).
Analyzing the options:
- **a. Single super phosphate**: Contains only Phosphorus (P). Therefore, it is a straight fertilizer. (Correct)
- **b. Diammonium phosphate (DAP)**: Contains Nitrogen (N) and Phosphorus (P). It is a complex fertilizer. (Incorrect)
- **c. Ammonium potassium phosphate**: Contains Nitrogen (N), Phosphorus (P), and Potassium (K). It is a complex fertilizer. (Incorrect)
- **d. Soluble NPK**: Contains Nitrogen (N), Phosphorus (P), and Potassium (K). It is a mixed or complex fertilizer. (Incorrect)
Most common weed in rice.
A)
Cyperus spp
B)
Vicoa spp
C)
Echinochloa spp
D)
Celosia spp
Step-by-step reasoning:
1. Rice (Oryza sativa) is grown in flooded conditions, meaning the most competitive weeds are those that can tolerate anaerobic conditions and mimic the morphology of the rice plant.
2. Echinochloa spp. (commonly known as Barnyard grass) is widely recognized as the most problematic and common weed in rice globally. Because it belongs to the same family (Poaceae) as rice, it is morphologically very similar, making manual weeding difficult during early growth stages.
3. Analysis of other options:
- Cyperus spp. (Sedges) are common in rice fields, but they are generally less dominant and easier to manage than the grass weeds like Echinochloa.
- Vicoa spp. is not a primary or common weed associated with rice cultivation.
- Celosia spp. (Cock's comb) is a broad-leaved weed that may occur occasionally but is not a dominant or 'most common' weed in rice ecosystems.
4. Therefore, based on agronomic prevalence and impact, Echinochloa spp. is the correct answer.
Bajra (Pearl millet) generally contain ___________ protein.
A)
20%
B)
10.5%
C)
12.5%
D)
11.6%
Bajra (Pearl Millet, Pennisetum glaucum) is a nutrient-dense cereal crop known for its high mineral content and protein levels compared to some other cereals. In agricultural science and crop nutrition data, the average protein content of Pearl Millet is generally cited around 11% to 12%. Specifically, in many technical textbooks used for competitive exams in agriculture, the standard value provided for the protein content of Bajra is 11.6%.
Comparing the options:
- 20% is too high for a cereal grain (this is closer to legume levels).
- 10.5% is slightly lower than the average for high-quality pearl millet.
- 12.5% is on the higher end of the spectrum but not the standard representative value.
- 11.6% is the precise value often cited in crop science literature for the general protein composition of Bajra.
India is situated in the:
A)
South-west trade wind zone
B)
North-east trade wind zone
C)
East-west trade wind zone
D)
Easterly trade wind zone
Step-by-step reasoning: 1. Trade winds are the permanent east-to-west winds that flow in the tropics. 2. In the Northern Hemisphere, these winds blow from the subtropical high-pressure belt (around 30°N) towards the equatorial low-pressure belt (the ITCZ). 3. Because they blow from the northeast toward the southwest, they are called the 'North-East Trade Winds'. 4. India is located primarily between 8°N and 37°N latitude, placing it squarely within the Northern Hemisphere's tropical and subtropical zone. 5. Therefore, India is situated in the North-east trade wind zone. Option (a) is incorrect as South-west trade winds occur in the Southern Hemisphere. Options (c) and (d) are not standard meteorological classifications for the specific trade wind belts of the hemispheres.
Acidic soils are generally deficient in:
A)
P
B)
Fe
C)
Cu
D)
Al
Soil pH significantly influences the availability of essential plant nutrients. In acidic soils (typically pH < 5.5), the availability of Phosphorus (P) decreases sharply. This happens because phosphorus reacts with soluble aluminum (Al) and iron (Fe) to form insoluble compounds (aluminum phosphates and iron phosphates), a process known as 'phosphorus fixation.' Consequently, P becomes unavailable for plant uptake, making acidic soils generally deficient in P.
Regarding the other options:
- b. Fe (Iron) and c. Cu (Copper): These micronutrients become more soluble and more available as soil pH decreases. In very acidic soils, they can even reach toxic levels.
- d. Al (Aluminum): Aluminum is not a nutrient but a metal that becomes highly soluble and toxic to plants in acidic soils. It is present in abundance (available form) in acidic soils, not deficient.
___________ fertilizer is given as top dressing
A)
P
B)
N
C)
S
D)
K
Top dressing is the application of fertilizer to the soil surface around the plants after they have been established. Nitrogen (N) is the primary nutrient applied as a top dressing because it is highly mobile in the soil and prone to leaching (washing away with water). To ensure the plant has access to nitrogen during its peak growth stages and to prevent loss, it is applied in split doses on the surface. In contrast, Phosphorus (P) and Potassium (K) are relatively immobile in the soil and are typically applied as basal dressings (incorporated into the soil before or during planting) to ensure they are available near the root zone throughout the crop cycle. Sulfur (S) is also generally applied as a basal dose or through specific soil amendments.
According to USDA soil texture classification, silt is ___________ mm.
A)
0.05 to 0.1
B)
0.002 to 0.02
C)
< 0.002
D)
0.002 to 0.05
According to the USDA (United States Department of Agriculture) soil texture classification system, soil separates are categorized based on their particle diameter as follows:
1. **Sand**: Particles with a diameter between 0.05 mm and 2.0 mm.
2. **Silt**: Particles with a diameter between 0.002 mm and 0.05 mm.
3. **Clay**: Particles with a diameter less than 0.002 mm.
Analyzing the options:
- Option (a) 0.05 to 0.1 mm falls within the range of sand.
- Option (b) 0.002 to 0.02 mm is a subset of the silt range but does not represent the full classification boundary.
- Option (c) < 0.002 mm defines clay particles.
- Option (d) 0.002 to 0.05 mm exactly matches the USDA definition for silt.
Low pressure area near the equator are called:
A)
Equinox
B)
Polar calms
C)
Burst
D)
Doldrums
The correct answer is 'Doldrums'. In climatology, the Doldrums refer to the Intertropical Convergence Zone (ITCZ), a belt of low pressure circling the Earth near the equator. In this region, the trade winds from the Northern and Southern Hemispheres meet. Because the intense solar heating causes air to rise vertically rather than flow horizontally, there is very little surface wind, leading to the characteristic 'calms' associated with this area.
Why other options are incorrect:
- a. Equinox: This is an astronomical event occurring twice a year when the sun is exactly above the equator, making day and night of equal length; it is not a pressure system.
- b. Polar calms: While there are areas of low wind in polar regions, the specific term for the equatorial low-pressure belt is the Doldrums.
- c. Burst: In meteorology, a 'burst' (such as a monsoon burst) refers to a sudden increase in rainfall or wind intensity, not a permanent pressure zone.
Sunflower is a native of:
A)
USA
B)
Spain
C)
India
D)
Africa
The sunflower (Helianthus annuus) is native to North America, specifically the central region of the United States and Mexico. It was domesticated by Native Americans long before it was introduced to Europe and Asia.
- Option (a) USA: Correct, as the plant originates from the North American continent.
- Option (b) Spain: Incorrect. While Spanish explorers are credited with bringing the sunflower from the Americas to Europe in the 16th century, it is not native to Spain.
- Option (c) India: Incorrect. Sunflower was introduced to India much later for commercial oil production.
- Option (d) Africa: Incorrect. The plant does not originate from the African continent.
___________ is allowed to be used in organic farming.
A)
Urea
B)
Rock phosphate
C)
NPK
D)
DAP
Organic farming prohibits the use of synthetic, chemically manufactured fertilizers.
1. **Urea (a)**: This is a synthetic nitrogen fertilizer produced via the Haber-Bosch process. It is strictly prohibited in organic farming.
2. **Rock phosphate (b)**: This is a naturally occurring mineral phosphate (phosphorite). Because it is a raw, minimally processed mineral rather than a chemically synthesized compound, it is generally permitted in organic farming to supplement phosphorus levels, provided it does not contain prohibited additives.
3. **NPK (c)**: This refers to synthetic compound fertilizers containing Nitrogen, Phosphorus, and Potassium. These are manufactured chemicals and are not allowed.
4. **DAP (d)**: Di-ammonium Phosphate is a highly soluble synthetic fertilizer produced by reacting ammonia with phosphoric acid. It is prohibited in organic farming.
Therefore, Rock phosphate is the only naturally derived mineral among the options that is acceptable under organic certification standards (such as IFOAM or NPOP).
___________ makes the seed more uniform in size, weight and shape.
A)
Pelleting
B)
Priming
C)
Roughing
D)
Blenching
Pelleting is a seed treatment process where seeds (especially very small or irregularly shaped ones) are coated with inert materials (like clay, talc, or lime) and binders to create a uniform, spherical shape. This process makes the seeds more uniform in size, weight, and shape, which is critical for precision planting using mechanical seed drills, as it ensures accurate seed spacing and depth.
Why other options are incorrect:
- b. Priming: This is a pre-sowing treatment involving controlled hydration of seeds to synchronize and accelerate germination; it does not change the physical size or shape of the seed.
- c. Roughing: This is the process of identifying and removing 'off-types' or diseased plants from a seed production field to maintain genetic purity.
- d. Blenching: This is not a standard term in seed technology; it is typically associated with food processing (blanching) or whitening of materials.
Soybean seed contain ___________ % protein.
A)
15
B)
30
C)
20
D)
40
Soybean (Glycine max) is renowned as one of the richest plant-based sources of protein. On average, soybean seeds contain approximately 36% to 45% protein by dry weight. Among the given options, 40% is the most accurate representation of the typical protein content found in soybean seeds.
Breakdown of options:
- Option (a) 15%: This is too low; typical of some cereals or low-protein legumes.
- Option (b) 30%: While some varieties may fall near this range, it is below the standard average for high-quality soybeans.
- Option (c) 20%: This is characteristic of many other pulses (like peas or lentils) but is significantly lower than soybean protein levels.
- Option (d) 40%: This aligns with the established scientific data for soybean protein content (typically cited as ~40%).
___________ is the practice of growing protective crops and row crops in alternative strips on the contours.
A)
Strip cropping
B)
Contour cropping
C)
Selective cropping
D)
Relay cropping
Step-by-step reasoning:
1. **Definition of Strip Cropping**: Strip cropping is a soil conservation method where different crops are grown in alternating strips. Typically, a 'row crop' (like corn or sorghum), which leaves the soil bare and prone to erosion, is alternated with a 'protective crop' (like clover, grass, or legumes), which provides dense ground cover to trap soil and slow down runoff.
2. **Application on Contours**: To maximize effectiveness in preventing soil erosion on slopes, these strips are planted across the slope following the contour lines (contour strip cropping).
3. **Evaluating other options**:
- **Contour cropping (b)**: This is the general practice of plowing and planting across the slope. While strip cropping often uses contours, contour cropping refers to the general alignment, not specifically the alternation of protective and row crops.
- **Selective cropping (c)**: This is not a standard technical term for a soil conservation practice involving alternating strips.
- **Relay cropping (d)**: This is a method where a second crop is planted into an existing standing crop before the first one is harvested. It relates to time/seasoning rather than spatial strips for erosion control.
Under the land capability classes, Class II is denoted by:
A)
Red
B)
Green
C)
Yellow
D)
Black
In the Land Capability Classification (LCC) system, land is categorized into eight classes (I to VIII) based on its suitability for cultivation and the limitations present. To make these maps easily readable, a standardized color-coding system is used.
1. Class I: Denoted by Light Green (Very good land, few limitations).
2. Class II: Denoted by Yellow (Good land, some limitations).
3. Class III: Denoted by Dark Yellow or Orange (Moderately good land).
4. Class IV: Denoted by Red (Fairly good land, severe limitations).
5. Class V to VIII: Usually denoted by various shades of brown, grey, or blue depending on the specific mapping standard used for non-arable or forest lands.
Therefore, Class II land, which has slight limitations that can be overcome by simple conservation practices, is represented by the color Yellow.
The final product of nitrification.
A)
NO
B)
NO2
C)
NH
D)
Elemental N
Nitrification is a two-step biological process in the nitrogen cycle where ammonia is oxidized to nitrate.
Step 1: Ammonia (NH3/NH4+) is oxidized to Nitrite (NO2-) primarily by bacteria such as Nitrosomonas.
Step 2: Nitrite (NO2-) is further oxidized to Nitrate (NO3-) primarily by bacteria such as Nitrobacter.
Analyzing the options provided:
- Option (a) NO (Nitric oxide) is a product of denitrification, not nitrification.
- Option (b) NO2 (Nitrite) is an intermediate product. However, looking at the provided options, NO3 (Nitrate) is missing. In many exam contexts where NO3 is absent but NO2 is present, NO2 is the closest chemical species related to the nitrification pathway provided, although technically Nitrate (NO3-) is the final stable product. Given the choices, NO2 represents the oxidized nitrogen species resulting from the process.
- Option (c) NH (Imidogen) is not a standard product of this cycle.
- Option (d) Elemental N (N2) is the final product of denitrification, not nitrification.
Note: While the scientifically accurate final product is Nitrate (NO3-), among the given choices, NO2 is the only one that is a direct product of the nitrification sequence.
Foundation seed is labelled in ___________ colour.
A)
White
B)
Blue
C)
Green
D)
Golden yellow
In seed technology, seed classes are identified by specific colors of tags attached to the seed bags to ensure quality control and traceability. The standard color coding is as follows:
1. Nucleus Seed: No tag (or sometimes a yellow tag in specific contexts, but generally not tagged in the same way as certified classes).
2. Breeder Seed: Golden Yellow tag.
3. Foundation Seed: White tag.
4. Registered Seed: Purple tag.
5. Certified Seed: Azure Blue tag.
Therefore, Foundation seed is labeled with a white tag. Option (b) Blue is for Certified seed, (c) Green is not a standard seed class tag color, and (d) Golden yellow is for Breeder seed.