Dryland Agriculture Topic -1 — Agri Master Mind

The All India Coordinated Research Project for Dryland Agriculture (AICRPDA) was launched in 1970 in collaboration with the Government of Canada. How many initial centers were established under this project?
  • 17
  • 23
  • 47
  • 100
The AICRPDA was launched with 23 centres and a Coordinating Cell at Hyderabad. This specific number is a key detail in the history of systematic dryland research in India.
According to the classification based on users, a 'Hydrological Drought' results from:
  • A period of abnormally dry weather with low air humidity.
  • An imbalance between soil moisture and crop evapotranspiration.
  • A prolonged meteorological drought.
  • A rainfall deficit of more than 50% of the long-term average.
Hydrological drought is defined by its cause-and-effect relationship; it occurs when a prolonged period of meteorological drought (lack of precipitation) leads to depleted water resources in streams, rivers, and reservoirs.
The 'diurnal and cyclic water stress' differs from other droughts because:
  • It is a permanent feature of desert climates.
  • It is caused by a lack of moisture conservation practices.
  • The plant recovers from the stress periodically, either daily or between irrigations.
  • It occurs due to high osmotic pressure in the soil solution.
This type of stress is temporary and reversible. Diurnal stress occurs during the day with recovery at night, and cyclic stress builds between irrigations and disappears after watering, distinguishing it from prolonged, irreversible droughts.
The Drought Prone Areas Programme (DPAP) was launched by the Central Government in which year?
  • 1970-71
  • 1973-74
  • 1990-91
  • 2005-06
This is a specific historical fact related to government initiatives for drought management. The year 1973-74 is marked as the launch year for DPAP.
In the context of dryland agriculture, what does the acronym CAZRI stand for?
  • Central Arid Zone Research Institute
  • Committee for Arid Zone Resource Inventory
  • Central Agriculture and Zonal Research Institute
  • Cultivation Advice for Arid Zone Regions of India
CAZRI is a premier research institution established in 1959 in Jodhpur, focusing on arid zone agriculture. Knowing the full form of such key institutes is essential.
The National Agricultural Technology Project (NATP) was initiated in which year?
  • 1979
  • 1990
  • 1998
  • 2005
This question tests knowledge of the chronology of important agricultural research projects in India. NATP was a World Bank-supported project launched in 1998.
Consider the following statements about the Rashtriya Krishi Vikas Yojana (RKVY) sub-scheme, Rainfed Area Development (RAD): It is a sub-scheme of the National Mission for Sustainable Agriculture (NMSA). Its primary objective is to promote integrated farming systems. I t provides financial assistance of up to Rs. 50,000 per family for adoption of integrated farming. Which of the statements given above is/are correct?
  • 1 and 2 only
  • 2 only
  • 2 and 3 only
  • 1, 2 and 3
Statements 1 and 2 are accurate descriptions of the RAD scheme. However, Statement 3 is incorrect because the financial assistance mentioned is up to Rs. 30,000 per family, not Rs. 50,000.
Which of the following statements regarding the distinction between arid/semiarid and tropical/temperate regions is/are correct? Arid and semiarid regions are classified based on moisture regimes. Tropical and temperate regions are classified based on thermal regimes. An arid region can also be a temperate region. Select the correct answer using the code given below:
  • 1 only
  • 1 and 2 only
  • 2 and 3 only
  • 1, 2 and 3
Statements 1 and 2 are correct as they define the basis of classification (moisture vs. temperature). Statement 3 is also correct; these classifications are independent. For example, a cold desert like Ladakh is both arid and temperate.
With reference to drought identification criteria in different Indian states, which of the following pairs is correctly matched?
  • Tamil Nadu : Drought if rainfall is less than 400 mm in Kharif
  • Karnataka : Drought if rainfall is less than 900 mm annually
  • Rajasthan : Scarcity year if productivity decreases by 50% compared to a good year
  • All India : Drought if spatial coverage is less than 20%
This is the specific criterion mentioned for Rajasthan. The other pairs are mismatched: Tamil Nadu uses <900 mm, Karnataka uses <400 mm in Kharif, and an all-India severe drought is when spatial coverage is >40%.
Assertion (A): Invisible drought can occur in humid regions. Reason (R): It results from rainfall being less than evapotranspiration losses, causing borderline water deficiency that reduces yield without visible wilting.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is correct as invisible drought is specifically noted to occur in humid regions. The Reason accurately explains the mechanism behind this phenomenon: a subtle water deficit where ET exceeds rainfall, leading to yield loss without obvious drought symptoms.
Assertion (A): The productivity of dryland agriculture is crucial for India's food security. Reason (R): Rainfed agriculture contributes 40% of the country's total food grain production.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is a valid inference. The Reason provides a substantial quantitative fact that directly explains why dryland agriculture is so crucial—because it produces a very significant portion (40%) of the nation's food grains.
Assertion (A): Wind erosion is a constraint in dryland farming but not in rainfed farming. Reason (R): Dryland farming is practiced in arid and semi-arid regions which are more prone to wind erosion, whereas rainfed farming is practiced in humid regions with better vegetation cover.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The UNESCAP table lists "Wind and water erosion" as a constraint for dryland farming and only "Water erosion" for rainfed farming. The Reason correctly explains this by linking the type of erosion to the typical environmental conditions of each farming system.
The 'ecological drought' primarily affects:
  • Urban water supply systems
  • The primary productivity of natural or managed ecosystems
  • The socio-economic conditions of farmers
  • The ability of plants to absorb water from the soil
Ecological drought is defined by its impact on ecosystems. It is a rainfall deficit that leads to a decline in primary productivity, affecting the entire ecological community, not just agricultural or human systems.
The National Watershed Development Project for Rainfed Areas (NWDPRA) was operational in how many states and Union Territories during 1990-91?
  • 15 states
  • 25 states and 2 UTs
  • All states and UTs
  • 10 states in the arid zone
This is a specific detail about the scale of the NWDPRA program. Knowing the extensive reach of this project (25 states and 2 UTs) highlights the national priority given to watershed development in rainfed areas.
The concept of "Length of Growing Period (LGP)" is directly related to the relationship between:
  • Actual Evapotranspiration (AET) and Potential Evapotranspiration (PET)
  • Soil type and crop variety
  • Annual rainfall and irrigation potential
  • Economic input and output
The Length of Growing Period is determined by the period when soil moisture is sufficient for plant growth, which is defined by the balance between AET and PET. When AET falls significantly below PET, moisture stress begins, defining the end of the effective growing period.
According to the key agricultural statistics for India (2021–22), what is the approximate ratio of rainfed area to the net sown area?
  • 1:2
  • 3:5
  • 4:7
  • 5:8
India’s net sown area is about 141 million ha, of which ~80 million ha is rainfed. Thus, the ratio of rainfed to net sown area is 80:141 ≈ 4:7. This tests the candidate’s ability to interpret agricultural statistics quantitatively.
The first systematic scientific approach to tackle dry farming problems in India was initiated by Tamhane in 1923. Where was this pioneering research station located?
  • Bijapur
  • Manjri near Pune
  • Rohtak
  • Hyderabad
The first organized dry farming research in India was started at Manjri Farm near Pune (1923) under Dr. Tamhane. This marks the beginning of formal dryland research in India.
A region in India is officially classified as ‘rainfed’ for agricultural purposes when assured irrigation is provided to less than what percentage of the net sown area?
  • 25%
  • 40%
  • 50%
  • 75%
Areas where less than 40% of the net sown area is under assured irrigation are classified as rainfed regions. This classification guides developmental and watershed interventions.
Which of the following soil types occupies the largest area under Indian dryland agriculture?
  • Laterite
  • Alluvial
  • Black
  • Red
Although black soils dominate certain dry regions, alluvial soils cover the largest geographical area under cultivation in India, including significant portions of rainfed agriculture.
Based on UNESCAP classification, which combination of characteristics is typical for dryland farming?
  • Rainfall >800 mm, Growing season >200 days, Double cropping
  • Rainfall <800 mm, Growing season <200 days, Single crop or intercropping
  • Rainfall >1150 mm, Growing season >200 days, Intercropping
  • Rainfall 750–1150 mm, Growing season ~200 days, Water erosion constraint
Dryland farming occurs in areas with <800 mm rainfall and <200 days growing period, where moisture stress restricts cropping to single or intercropped systems.
The South-West monsoon (June–September) contributes what percentage of India’s total annual precipitation?
  • 10%
  • 13%
  • 74%
  • 100%
About 74% of India’s total annual rainfall occurs during the South-West monsoon (June–September), which determines the cropping pattern and productivity of rainfed systems.
The condition where crops cannot absorb soil water due to high osmotic pressure is termed as:
  • Meteorological drought
  • Physiological drought
  • Hydrological drought
  • Socio-economic drought
Physiological drought occurs when soil moisture is present but unavailable to plants due to high salt concentration (osmotic effect), leading to wilting despite moist soil.
The National Rainfed Area Authority (NRAA) was constituted by the Government of India in which year?
  • 1990
  • 1998
  • 2005
  • 2006
The NRAA was established in 2006 under the Ministry of Agriculture to coordinate and monitor policies for sustainable management of rainfed areas.
Consider the following statements about dryland crops in India: Over 85% of the area under pulses is rainfed. Dryland farming contributes to more than two-thirds of the area under oilseeds. The majority of the area under wheat and rice is dryland. Which of the statements given above is/are correct?
  • 1 only
  • 1 and 2 only
  • 2 and 3 only
  • 1, 2 and 3
About 88% of pulses and ~69% of oilseeds are rainfed. However, wheat (≈19%) and rice (≈40%) are largely irrigated; hence statement 3 is incorrect.
Which of the following statements about drought is/are correct? Aridity is a permanent climatic feature, while drought is a temporary condition. As per the Irrigation Commission of India, drought is declared when annual rainfall is <75% of normal. A ‘Severe drought year’ is declared when the spatial coverage of drought exceeds 20%.
  • 1 and 2 only
  • 2 only
  • 1 and 3 only
  • 1, 2 and 3
Statements 1 and 2 are correct. Statement 3 is wrong — a severe drought year is declared when drought affects >40% of the country’s area.
With reference to the history of dryland agriculture research in India, which pair is correctly matched?
  • 1959 – Establishment of ICRISAT, Hyderabad
  • 1970 – Launch of AICRPDA by ICAR
  • 1985 – Establishment of CAZRI
  • 2005 – Constitution of NRAA
The All India Coordinated Research Project on Dryland Agriculture (AICRPDA) was launched in 1970. ICRISAT was set up in 1972, CAZRI in 1959, and NRAA in 2006.
Consider the following statements: All arid and semiarid regions are classified as dry farming areas. Dryland farming is a subset of rainfed agriculture practiced in moisture-deficit regions. The terms “arid/semiarid” and “tropical/temperate” refer to moisture and thermal regimes respectively. Which are correct?
  • 1 and 2 only
  • 2 and 3 only
  • 1 and 3 only
  • 1, 2 and 3
Statement 1 is false (irrigation exists in arid zones). Statements 2 and 3 are correct — dryland farming refers to moisture-deficit rainfed agriculture, and arid/semiarid indicate moisture regimes.
Which of the following is a characteristic unique to dry farming?
  • Crop failures are less frequent
  • Practiced in humid regions
  • Prolonged dry spells during crop period are most common
  • Cultivation where rainfall >1150 mm/year
Dry farming regions (arid/semiarid) experience frequent and long dry spells during crop growth, unlike rainfed regions with higher rainfall and fewer dry periods.
Assertion (A): In India, rainfed agriculture contributes about 40% of the total food grain production. Reason (R): Nearly 80 million hectares of the net sown area is under rainfed cultivation.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
Both statements are true; however, production contribution depends not only on area but also on crop type and productivity, not area alone.
Assertion (A): Dryland farming and rainfed farming are not synonymous. Reason (R): Dryland farming is a subset of rainfed agriculture practiced in arid and semiarid regions with severe moisture stress.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The terms differ technically — all dryland farming is rainfed, but not all rainfed farming is dryland. The reason correctly explains this relationship.
Assertion (A): A ‘dry spell’ is defined differently for light and heavy soils. Reason (R): Heavy soils retain more moisture, enabling crops to withstand longer rainless periods.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
A dry spell is >10 days in light soils and >15 days in heavy soils due to differences in water-holding capacity, validating both statements.
Assertion (A): The productivity of dryland crops is lower than that of irrigated crops. Reason (R): It takes about three hectares of dryland to produce the cereal yield equivalent to one hectare of irrigated land.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The yield gap between rainfed and irrigated systems is large — primarily due to moisture limitation, validating both the statement and explanation.
Assertion (A): A drought for one crop may not be a drought for another. Reason (R): This relative drought occurs due to mismatch between soil moisture and the crop’s water requirement.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
Known as Relative (Apparent) Drought, this concept recognizes crop-specific moisture requirements — both statements are correct and linked.
The ‘RAD’ sub-scheme promoting Integrated Farming Systems in rainfed areas falls under which national mission?
  • National Mission on Sustainable Agriculture (NMSA)
  • National Water Mission
  • National Mission on Oilseeds and Oil Palm
  • National Food Security Mission
Rainfed Area Development (RAD) is a sub-scheme of the NMSA, aiming to promote climate-resilient integrated farming in rainfed regions.
According to Ramdas (1960), drought occurs when actual seasonal rainfall is deficient by more than:
  • The mean deviation
  • Twice the mean deviation
  • Thrice the mean deviation
  • Half the standard deviation
As per L.A. Ramdas (1960), drought is defined when the seasonal rainfall deficiency exceeds twice the mean deviation from normal rainfall.
Which institution was established in 1959 for arid zone research?
  • CRIDA
  • ICRISAT
  • CAZRI
  • ICRIDA
The Central Arid Zone Research Institute (CAZRI), Jodhpur, was founded in 1959 to promote research on arid zone management and dryland farming.
A ‘contingent drought’ typically occurs in which type of climatic region?
  • Desert climate
  • Arid and semi-arid zones
  • Humid or sub-humid climates
  • All of the above
Contingent drought is an occasional, short-term drought in otherwise humid/sub-humid regions, caused by temporary rainfall failure.
The financial assistance for adopting Integrated Farming Systems under RAD is up to:
  • ₹10,000 per family
  • ₹20,000 per family
  • ₹30,000 per family
  • ₹50,000 per family
Under the RAD component of NMSA, assistance of up to ₹30,000 per family is provided for establishing integrated farming models in rainfed areas.
Which of the following represents a ‘mid-season drought’?
  • Delay in the onset of monsoon
  • Long gaps between two rainfall events
  • Early withdrawal of rainfall
  • Drought in desert climates
Mid-season drought refers to dry spells during crop growth due to prolonged gaps between rainfall events, affecting yield and plant growth.
The word ‘arid’ is derived from the Latin word ‘arere’, which means:
  • Thirsty
  • Dry
  • Barren
  • Hot
The term ‘arid’ originates from the Latin word arere, meaning “to be dry”, aptly describing regions with severe moisture deficiency.
Among the different types of resistances in gas exchange, which one is characterized by being highly variable and responsive to environmental factors like light, CO₂, and plant water status?
  • Boundary Resistance
  • Cuticular Resistance
  • Mesophyll Resistance
  • Stomatal Resistance
Stomatal resistance is highly variable and primarily controlled by guard cells. It changes rapidly with light, CO₂ concentration, humidity, and plant water status. Boundary and mesophyll resistances remain relatively constant.
The ability of a crop to grow satisfactorily under water stress is specifically termed as:
  • Drought Evasion
  • Drought Adaptation
  • Drought Mitigation
  • Drought Resistance
Drought adaptation is the overall capacity of a plant to maintain growth and yield under limited water. It includes mechanisms like drought escape, avoidance, and tolerance.
Which of the following is a key characteristic of plants that employ the 'drought escaping' mechanism?
  • Maintenance of high osmotic pressure
  • Early stomatal closure
  • Ephemeral life cycle or early maturation
  • Development of an efficient root system
Drought escape is achieved by completing the life cycle before severe drought occurs, as seen in short-duration or ephemeral crops.
In the context of drought avoidance, 'water savers' primarily achieve a favorable water balance by:
  • Accelerating water uptake
  • Restricting transpiration
  • Storing large volumes of water
  • Tolerating low tissue water potential
Water savers reduce water loss by controlling transpiration through mechanisms like stomatal closure, leaf rolling, and waxy cuticles.
A key physiological advantage of C4 plants over C3 plants under moisture stress is:
  • Higher CO₂ compensation point
  • Use of RuBisCO as primary enzyme
  • Higher photosynthetic efficiency at same stomatal conductance
  • Keeping stomata open during the day
C4 plants use PEP carboxylase, which efficiently fixes CO₂ even with limited stomatal opening, improving water-use efficiency under drought.
Plants with Crassulacean Acid Metabolism (CAM) are highly drought resistant because they:
  • Keep stomata open during the day
  • Perform all gas exchange during daylight
  • Open stomata at night and store CO₂ as organic acids
  • Have very low mesophyll resistance
CAM plants open stomata at night when humidity is high, storing CO₂ as malic acid for daytime photosynthesis—reducing water loss.
The primary function of leaf pubescence (hairiness) in drought adaptation is to:
  • Increase boundary layer resistance
  • Increase leaf reflectance and reduce radiation load
  • Absorb atmospheric moisture
  • Deposit lipids on leaf surface
Leaf hairs reflect sunlight, lower leaf temperature, and reduce transpiration—important for water conservation in arid conditions.
What is the reported contribution of awns to grain photosynthesis in drought conditions?
  • 5%
  • 12%
  • 25%
  • 40%
Awns contribute about 12% of total photosynthesis to grain filling under drought, helping maintain yield when leaves senesce early.
Consider the following statements about resistances to gas exchange: Boundary resistance is influenced by wind speed and leaf morphology. Mesophyll resistance is highly variable and the major control point for gas exchange. Stomatal resistance values typically range from 100–2000 s/m. Which of the above are correct?
  • 1 only
  • 1 and 3 only
  • 2 and 3 only
  • 1, 2 and 3
Boundary resistance depends on wind and leaf size; stomatal resistance usually ranges between 100–2000 s/m. Mesophyll resistance is relatively stable, not highly variable.
Which mechanisms are associated with 'Water Savers' in drought avoidance? Lipid deposition on foliage High root-to-top ratio Reduction in leaf area Water storage in tissues
  • 1 and 3 only
  • 1, 2 and 3
  • 1, 3 and 4
  • 2 and 4
Water savers reduce transpiration through leaf surface lipid deposition and smaller leaf area. Root-to-top ratio relates to water spenders, not savers.
With reference to C3 and C4 plants, which statements are correct? C4 plants have higher CO₂ compensation point. Primary carboxylating enzyme in C4 plants is PEP carboxylase. Sorghum and pearl millet are examples of C4 plants.
  • 1 and 2
  • 2 and 3
  • 1 and 3
  • 1, 2 and 3
C4 plants use PEP carboxylase for CO₂ fixation and have a low CO₂ compensation point. Sorghum and pearl millet are typical C4 species.
Which statements about drought adaptation are correct? Ephemerals avoid drought through short life cycles. Drought tolerance involves maintaining turgor via osmotic adjustment. Stomatal closure is a mechanism of drought escape.
  • 1 and 2 only
  • 2 only
  • 1 and 3
  • 1, 2 and 3
Drought tolerance involves osmotic and protoplasmic adjustments; ephemerals escape drought by rapid growth. Stomatal closure is avoidance, not escape.
Assertion (A): Grasses often exhibit leaf rolling under moisture stress. Reason (R): Leaf rolling reduces exposed surface area and limits transpiration.
  • Both A and R are true, and R is the correct explanation of A.
  • Both A and R are true, but R is NOT the correct explanation of A.
  • A is true, but R is false.
  • A is false, but R is true.
Leaf rolling reduces radiation interception and transpiration rate, conserving water during stress.
Assertion (A): Awned cereals perform better under drought. Reason (R): Awns contribute to photosynthesis with low transpirational loss.
  • Both A and R are true, and R is the correct explanation of A.
  • Both A and R are true, but R is NOT the correct explanation of A.
  • A is true, but R is false.
  • A is false, but R is true.
Awns continue photosynthesis during leaf senescence, supporting grain filling with minimal water loss.
Assertion (A): Mesophyll resistance affects photosynthetic capacity. Reason (R): It governs CO₂ diffusion from substomatal cavities to chloroplasts.
  • Both A and R are true, and R is the correct explanation of A.
  • Both A and R are true, but R is NOT the correct explanation of A.
  • A is true, but R is false.
  • A is false, but R is true.
Higher mesophyll resistance limits CO₂ reaching carboxylation sites, reducing photosynthesis efficiency.
Assertion (A): Drought-resisting varieties open stomata rapidly in early morning. Reason (R): Moisture stress is minimal in early morning, allowing efficient photosynthesis.
  • Both A and R are true, and R is the correct explanation of A.
  • Both A and R are true, but R is NOT the correct explanation of A.
  • A is true, but R is false.
  • A is false, but R is true.
Early-morning stomatal opening enables CO₂ uptake with low water loss due to high humidity.
Assertion (A): Leguminous plants orient leaves parallel to sunlight under drought. Reason (R): This paraheliotropic movement reduces radiation load and transpiration.
  • Both A and R are true, and R is the correct explanation of A.
  • . Both A and R are true, but R is NOT the correct explanation of A.
  • A is true, but R is false
  • A is false, but R is true.
Paraheliotropism reduces radiation interception, leaf temperature, and water loss.
The resistance influenced by leaf size and wind speed is:
  • Stomatal
  • Boundary Layer
  • Mesophyll
  • Cuticular
Boundary layer resistance depends on wind velocity, leaf shape, and size—thicker layers slow gas exchange.
Which plant uses water storage as a drought adaptation?
  • Soybean
  • Pearl millet
  • Pineapple
  • Sorghum
Pineapple stores water in succulent tissues and follows CAM photosynthesis for high drought tolerance.
The CO₂ compensation point is lowest in:
  • C3
  • C4
  • CAM
  • Both C3 and C4 equal
C4 plants maintain CO₂ concentration at RuBisCO sites, lowering the compensation point to 8–10 ppm compared to 40–100 ppm in C3 plants.
Stomata close when guard cells are:
  • Turgid
  • Flaccid
  • Full of water
  • Photosynthetically active
Loss of turgor in guard cells causes stomatal closure, reducing gas exchange and water loss.
The main advantage of early stomatal closure under drought is:
  • Maximize CO₂ intake
  • Prevent photorespiration
  • Conserve water
  • Accelerate leaf fall
Early stomatal closure limits transpiration, preserving internal water balance during stress.
Crops known to deposit lipids on their surfaces to reduce water loss include:
  • Wheat and Barley
  • Soybean and Sorghum
  • Rice and Maize
  • Chickpea and Pigeonpea
Lipid deposition forms a hydrophobic surface, reducing non-stomatal water loss under moisture stress.
The drought adaptation mechanism where plants maintain turgidity by accelerating water uptake is seen in:
  • Water Savers
  • Water Spenders
  • Drought Escapers
  • CAM Plants
Water spenders maintain water status through deep or extensive roots that increase water absorption from soil.
A plant that opens its stomata at night and fixes CO₂ into organic acids is a:
  • C3
  • C4
  • CAM
  • Halophyte
CAM plants fix CO₂ at night into malic acid and use it for photosynthesis during the day—an efficient drought survival strategy.
According to Thornthwaite's (1948) original classification, a region with a Precipitation Effectiveness (PE) Index of 28 would be classified as:
  • Humid
  • Sub-humid
  • Semi-arid
  • Arid
In Thornthwaite’s classification, Semi-arid (D) regions have a PE Index between 16 and 31. A PE value of 28 falls within this range, indicating semi-arid conditions.
The Thornthwaite classification system incorporates three primary components. Which of the following is NOT one of them?
  • Temperature Effectiveness (TE) Index
  • Precipitation Effectiveness (PE) Index
  • Seasonal distribution of rainfall
  • Soil moisture storage capacity
Thornthwaite’s system considers PE Index, TE Index, and seasonal rainfall distribution. Soil moisture storage capacity is not a direct component; it is considered in other systems like Papadakis’.
In the context of Troll's (1965) classification, a 'humid month' is defined as one where:
  • Mean rainfall exceeds mean potential evapotranspiration
  • Mean temperature exceeds 18°C
  • Moisture Availability Index (MAI) > 0.34
  • Number of growing days > 120
Troll’s system defines a humid month when mean monthly rainfall (MR) exceeds mean potential evapotranspiration (MPET), reflecting a positive moisture balance.
Based on the modified Troll’s classification used by ICRISAT, what percentage of India’s geographical area is constituted by Dry Semi-Arid Tropics?
  • 12.31%
  • 17.00%
  • 57.17%
  • 88.00%
According to ICRISAT’s adaptation of Troll’s classification, Dry Semi-Arid Tropics (2.0–4.5 humid months) cover about 57.17% of India’s total land area — the largest climatic zone in the country.
The Papadakis (1961) classification uses a Moisture Index (H) that incorporates which of the following unique parameters?
  • Dependable precipitation (75% probable rainfall)
  • Water stored from previous rainfall (W)
  • NDVI
  • Mean annual biotemperature
Papadakis introduced a Moisture Index defined as H = (P + W)/E, where W is the water stored from previous rainfall events — an innovation linking soil storage to climatic classification.
Hargreaves’ (1971) Moisture Availability Index (MAI) is distinctive because it uses:
  • Actual evapotranspiration / potential evapotranspiration
  • Sum of precipitation and stored soil water
  • Dependable precipitation (75% probable rainfall)
  • Length of growing period
Hargreaves’ MAI is calculated as the ratio of dependable (75% probable) precipitation to PET, making it more reliable for agricultural water planning under variable rainfall.
According to the FAO classification system, a region is classified as ‘semi-arid’ if its length of growing period (LGP) is:
  • 1–74 days
  • 75–119 days
  • 120–179 days
  • 180–269 days
FAO’s system is based on the growing period concept — the number of days precipitation exceeds half the PET. Semi-arid zones are defined by an LGP of 75–119 days.
In ICAR’s modification of Thornthwaite’s classification, a ‘Moisture Index’ value of -55 would place a region in which moisture belt?
  • Semi-dry
  • Dry
  • Slightly dry
  • Slightly moist
In ICAR’s eight-zone moisture classification, a Moisture Index between -40 and -60 corresponds to the “Dry” belt (Zone 3).
The Moisture Deficit Index (MDI) used by AICRPDA of ICAR classifies a region as ‘Semi-arid’ if its MDI value falls between:
  • 0 to -33.3
  • -33.3 to -66.6
  • -66.6 to -100
  • > -100
MDI = (P - PET)/PET. According to AICRPDA, semi-arid regions fall between -33.3 and -66.6, indicating moderate water deficit.
Which of the following chemicals is correctly matched with the crop for which it is used as a seed hardening agent?
  • KCl — Groundnut
  • CaCl₂ — Sorghum
  • Cycocel — Cotton
  • KH₂PO₄ — Pulses
Cycocel (CCC) is used for seed hardening in cotton. CaCl₂ is used for groundnut, KCl for maize, KH₂PO₄ for sorghum or pearl millet, and ash for pulses.
Film-forming antitranspirants, such as hexadecanol, primarily reduce water loss by:
  • Inducing stomatal closure
  • Increasing leaf albedo
  • Forming a physical barrier over stomata
  • Reducing plant growth rate
Film-forming antitranspirants create a thin physical layer on leaf surfaces, blocking stomatal diffusion of water vapor and reducing transpiration.
A region with a Normalized Difference Vegetation Index (NDVI) value of 0.25 would be classified as:
  • Arid
  • Semi-arid
  • Dry sub-humid
  • Sub-humid to humid
NDVI values between 0.2 and 0.3 represent semi-arid zones, indicating sparse to moderate vegetation cover and limited soil moisture.
According to Steiner et al. (1988), a region with a P/PET ratio of 0.35 would be classified as:
  • Hyper-arid
  • Arid
  • Semi-arid
  • Sub-humid
Steiner’s classification defines semi-arid regions where the precipitation-to-PET ratio ranges from 0.2 to 0.5. A value of 0.35 lies within this interval.
The ‘Per Humid’ region (A) in India, as per Thornthwaite’s classification, primarily includes:
  • The Gangetic plains
  • Western Rajasthan
  • Western Ghats and North-Eastern states
  • Eastern Maharashtra and Southern Gujarat
Regions receiving very high rainfall, such as the Western Ghats and most of Northeast India, are classified as “Per Humid” (A) under Thornthwaite’s system.
Which Indian state possesses the largest semi-arid area as a percentage of the total semi-arid area in the country?
  • Rajasthan
  • Maharashtra
  • Karnataka
  • Tamil Nadu
Maharashtra accounts for the largest share (around 19%) of India’s total semi-arid area, followed by Karnataka and Rajasthan.
In ICAR’s modified Troll classification (by Krishnan), a ‘Thorn Savannah’ climate is characterized by having how many humid months?
  • 12.0–9.5
  • 9.5–7.0
  • 7.0–4.5
  • 4.5–2.0
The “Thorn Savannah” (Dry Semi-Arid Tropics) is defined by 4.5 to 2.0 humid months in ICAR’s modified Troll classification.
The formula for the Temperature Effectiveness (TE) Index in Thornthwaite’s system is:
  • ∑(Mean Monthly Temperature °C)
  • P/E × 100
  • ∑(T − 32)/4, where T is in °F
  • (P − PET)/PET
The TE Index is calculated by summing (T − 32)/4 for each month, with T in °F. It quantifies the thermal component of climatic effectiveness.
A ‘severe drought period’ during the crop growing season is identified when:
  • AE > ½ PET
  • AE < ¼ PET
  • AE = PET
  • AE between ½ and ¼ PET
A severe drought occurs when Actual Evapotranspiration (AE) is less than one-fourth of Potential Evapotranspiration (PET), indicating extreme moisture stress.
Reflectant-type antitranspirants, such as kaolin, work primarily by:
  • Blocking stomatal pores
  • Increasing leaf reflectance and reducing leaf temperature
  • Forming hydrophobic films
  • Inhibiting aquaporins
Reflectantantitranspirants like kaolin increase leaf albedo (reflectivity), lowering leaf temperature and reducing transpiration losses.
Which classification system is explicitly noted for being based on the ‘growing period concept’?
  • Thornthwaite
  • Papadakis
  • FAO
  • Hargreaves
FAO’s agroclimatic classification is based on the growing period — defined as days when rainfall exceeds half the potential evapotranspiration (PET).
The symbol 'DA's' in Thornthwaite's classification stands for:
  • Dry Arid with summer drought
  • Semi-arid Tropical with summer drought
  • Semi-arid Mesothermal with adequate rainfall
  • Dry Arid with winter drought
D' represents Semi-arid, 'A' represents Tropical, and 's' represents summer rainfall deficit. Thus, 'DA's' means Semi-arid Tropical with rainfall deficit in summer.
According to the characteristics listed, crop production in arid regions is typically:
  • Possible with moisture conservation practices.
  • Not possible without irrigation.
  • Highly productive for wheat and rice.
  • Dependent on double cropping systems.
in arid regions, crop production is "not possible without irrigation," while in semi-arid regions, it is "possible with moisture conservation practices."
The Total Evapotranspiration (TE) index in Thornthwaite's system is used to classify:
  • Humidity provinces
  • Temperature provinces
  • Seasonal rainfall distribution
  • Moisture indices
The TE index, calculated from temperature data, is used to classify regions into temperature provinces like Tropical, Mesothermal, etc., which is separate from the humidity classification based on the PE index.
The best antitranspirants can reduce transpiration losses by up to:
  • 10-20%
  • 30-40%
  • 50-60%
  • 70-80%
In the modified Troll's classification, a region with 5.5 humid months would be classified as:
  • Arid
  • Semiarid-dry
  • Semiarid-wet
  • Humid
The modified Troll's classification table defines Semiarid-wet as having 4.5 to 7.0 humid months. The value 5.5 falls within this range.
Consider the following statements regarding the Thornthwaite classification system: It classifies climate based on PE Index, TE Index, and seasonal distribution of rainfall. The PE Index is calculated as (P/PE) * 100, where P is annual precipitation and PE is annual potential evapotranspiration. A region with a PE Index of 50 would be classified as 'Humid'. Which of the statements given above is/are correct?
  • 1 only
  • 1 and 2 only
  • 2 and 3 only
  • 1, 2 and 3
Statements 1 and 2 are correct definitions of the Thornthwaite system. Statement 3 is incorrect because a PE index of 50 falls in the 'Sub-humid' range (32-63), not the 'Humid' range (64-127).
Which of the following pairs of 'Classification System - Key Parameter' is correctly matched? Papadakis : Moisture Index (H) incorporating stored soil water Hargreaves : Moisture Availability Index (MAI) using dependable rainfall FAO : Length of Growing Period (LGP) based on P > 0.5 PET ICAR (AICRPDA) : Moisture Deficit Index (MDI) calculated as (P-PET)/PET Select the correct answer using the code given below:
  • 1 and 2 only
  • 1, 2 and 4 only
  • 2, 3 and 4 only
  • 1, 2, 3 and 4
Consider the following statements about India's climatic zones: Western Rajasthan is classified as an Arid region. Maharashtra has areas falling under both Dry Sub-humid and Semi-arid classifications. The Humid region covers the largest geographical area of India. Which of the statements given above is/are correct?
  • 1 only
  • 1 and 2 only
  • 2 and 3 only
  • 1, 2 and 3
Statement 1 is correct (Western Rajasthan is Arid). Statement 2 is correct (Maharashtra has Dry Sub-humid and Semi-arid areas). Statement 3 is incorrect; the Semi-arid-dry region (57.17%) is the largest, not the Humid region (1.10%).
With reference to antitranspirants, which of the following statements is/are correct? Stomatal closing types include chemicals like Phenyl Mercuric Acetate (PMA). Film-forming types include materials like cetyl alcohol. Reflectant types like kaolin spray can reduce leaf temperature. Select the correct answer using the code given below:
  • 1 and 2 only
  • 2 only
  • 2 and 3 only
  • 1, 2 and 3
PMA is a stomatal closer, cetyl alcohol is a film-former, and kaolin is a reflectant that reduces leaf temperature.
According to the document, which of the following statements regarding the Semi-Arid Tropics (SAT) is/are correct? ICRISAT classified SAT areas using Troll's classification. A SAT climate has between 5 to 10 arid months or 2 to 7 humid months. Dry SAT is characterized by 2.0 to 4.5 humid months. Select the correct answer using the code given below:
  • 1 only
  • 1 and 2 only
  • 2 and 3 only
  • 1, 2 and 3
ICRISAT used Troll's classification, which defines SAT by the number of arid/humid months, and the Dry SAT is further defined by 2.0-4.5 humid months.
Which of the following statements about the NDVI-based classification is/are correct? NDVI values range from -1.0 to +1.0. Water bodies typically show negative NDVI values. A value of 0.15 indicates a Hyper-arid region. Select the correct answer using the code given below:
  • 1 and 2 only
  • 2 only
  • 2 and 3 only
  • 1, 2 and 3
Statements 1 and 2 are correct as per the NDVI description. Statement 3 is incorrect; a value of 0.15 falls in the 'Arid' range (0.1-0.2), not 'Hyper-arid' (<0.1).
Consider the following statements: The Moisture Index (Im) of Thornthwaite and Mather (1955) can have negative values. The ICAR's moisture index classification has six categories. The formula PET = 2T (where T is average temperature in °C) is used in the MDI calculation by AICRPDA. Which of the statements given above is/are correct?
  • 1 only
  • 1 and 3 only
  • 2 and 3 only
  • 1, 2 and 3
Statement 1 is correct; the Im index ranges from negative (arid) to positive (per humid). Statement 3 is correct as per the MDI definition. Statement 2 is incorrect; the ICAR classification presented has eight moisture belts, not six
Assertion (A): In the FAO classification, the length of the growing period is a more direct agronomic measure than annual precipitation. Reason (R): The growing period considers the number of days when soil moisture from precipitation is sufficient to meet half the crop water demand.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is valid as LGP directly relates to the crop growth window. The Reason correctly explains that LGP is defined by the period when P > 0.5 PET, which is a proxy for when soil moisture is adequate for plant growth, making it a more functional agronomic metric than total annual rainfall.
Assertion (A): The Papadakis classification can be considered more agriculturally relevant than the original Thornthwaite classification for some applications. Reason (R): The Papadakis Moisture Index (H) incorporates water stored in the soil from previous rainfall events.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is a logical inference. The Reason provides the specific, correct explanation: by including stored soil water (W), the Papadakis index accounts for a key factor in plant water availability that Thornthwaite's PE index ignores, thereby increasing its agricultural relevance.
Assertion (A): According to the modified Troll's classification, the Humid climate zone covers the smallest percentage of India's geographical area. Reason (R): Humid climates in India are defined as having more than 7.0 humid months, a condition met only in small, specific regions like parts of the Western Ghats and Northeast.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is factually correct (1.10% area). The Reason correctly defines the Humid zone and explains why its spatial extent is limited in a predominantly semi-arid country like India.
Assertion (A): Seed hardening with KH₂PO₄ is recommended for crops like sorghum and pearl millet in dryland areas. Reason (R): KH₂PO₄ treatment improves the seed's osmotic adjustment capacity, enabling better germination and seedling establishment under moisture stress.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is a specific recommendation from the document. The Reason provides the correct physiological explanation for why this chemical is used for seed hardening in drought-prone crops.
Assertion (A): Reflectant-type antitranspirants are less likely to negatively impact photosynthesis than stomatal-closing types. Reason (R): Reflectantantitranspirants reduce transpiration by lowering leaf temperature, whereas stomatal closers directly restrict CO₂ entry.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is a recognized trade-off in antitranspirant use. The Reason correctly explains the mechanism: stomatal closers impede the pathway for CO₂ ingress, directly limiting photosynthesis, while reflectants act primarily on the energy balance, causing a lesser direct impact on gas exchange.
Assertion (A): The Moisture Deficit Index (MDI) used by AICRPDA typically yields negative values for most of India's dryland areas. Reason (R): The MDI is calculated as (P - PET)/PET, and in drylands, precipitation (P) is consistently lower than potential evapotranspiration (PET).
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is logically true for drylands. The Reason provides the mathematical and conceptual basis for why the MDI is negative—because the numerator (P-PET) is negative when P < PET, which is the defining characteristic of moisture-deficit regions.
Assertion (A): Hargreaves' use of 'dependable precipitation' makes his MAI index particularly useful for agricultural planning. Reason (R): Dependable precipitation (75% probable rainfall) accounts for variability and provides a more reliable estimate of water available for crops than mean annual precipitation.
  • Both A and R are true and R is the correct explanation of A.
  • Both A and R are true but R is NOT the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
The Assertion is a valid strength of Hargreaves' index. The Reason correctly explains that using a probability level (75%) offers a conservative and more realistic measure of water supply for risk-averse farm planning, making it superior to using average rainfall.