Agricultural Meteorology and Climate-Crop Relations MCQs 2026

The instrument commonly used to measure wind speed in an agrometeorological observatory is

1. A Barometer ✓
2. B Hygrometer ✓
3. C Anemometer ✓
4. D Pyrheliometer ✓

The primary source of energy for atmospheric processes and crop photosynthesis is

1. A Geothermal heat ✓
2. B Solar radiation ✓
3. C Soil respiration ✓
4. D Lunar radiation ✓

The branch of science that studies weather and climate in relation to crop production is called

1. A Agricultural meteorology ✓
2. B Agricultural economics ✓
3. C Soil taxonomy ✓
4. D Plant pathology ✓

Relative humidity in the field is most directly measured with a

1. A Rain gauge ✓
2. B Anemometer ✓
3. C Soil thermometer ✓
4. D Hygrometer ✓

The main purpose of a Stevenson screen at a weather station is to

1. A Collect rainfall without splash losses ✓
2. B Shield thermometers from direct radiation while allowing ventilation ✓
3. C Measure wind speed near crop canopy ✓
4. D Store soil samples at constant temperature ✓

The average environmental lapse rate in the lower atmosphere is approximately

1. A 6.5 C per km ✓
2. B 1.0 C per km ✓
3. C 15.0 C per km ✓
4. D 0.65 C per 100 km ✓

Growing degree days for a crop are commonly computed from

1. A Maximum temperature minus relative humidity ✓
2. B Rainfall divided by sunshine hours ✓
3. C Wind speed multiplied by vapour pressure ✓
4. D Mean daily temperature minus base temperature ✓

Base temperature in crop phenology means the temperature below which

1. A Photosynthesis is always maximum ✓
2. B Evaporation becomes zero ✓
3. C Crop development is assumed to be negligible ✓
4. D Respiration is permanently stopped ✓

The response of plants to relative length of day and night is known as

1. A Photoperiodism ✓
2. B Vernalization ✓
3. C Thermotropism ✓
4. D Hygroscopy ✓

A short-day plant generally flowers when the day length is

1. A Longer than its critical photoperiod ✓
2. B Exactly 24 hours ✓
3. C Shorter than its critical photoperiod ✓
4. D Independent of darkness duration ✓

The promotion of flowering by exposure of seed or seedlings to low temperature is called

1. A Photolysis ✓
2. B Vernalization ✓
3. C Senescence ✓
4. D Dormancy breaking by scarification ✓

Evapotranspiration from a cropped field includes

1. A Runoff and deep percolation ✓
2. B Photosynthesis and respiration ✓
3. C Rainfall and dew only ✓
4. D Soil evaporation and plant transpiration ✓

The FAO Penman-Monteith method is widely used to estimate

1. A Reference evapotranspiration ✓
2. B Soil organic carbon ✓
3. C Leaf area index directly ✓
4. D Crop harvest index ✓

The crop coefficient Kc is used in the equation

1. A Yield = Kc x seed rate ✓
2. B ETc = Kc x ETo ✓
3. C GDD = Kc x rainfall ✓
4. D LAI = Kc x temperature ✓

A lysimeter is mainly used in agrometeorology to measure

1. A Atmospheric pressure ✓
2. B Wind direction ✓
3. C Cloud type ✓
4. D Actual evapotranspiration ✓

Class A pan observations are primarily used to estimate

1. A Soil texture class ✓
2. B Atmospheric nitrogen ✓
3. C Evaporation demand ✓
4. D Leaf chlorophyll content ✓

Dew point is the temperature at which air becomes saturated and

1. A Wind speed becomes zero ✓
2. B Condensation begins ✓
3. C Photosynthesis stops ✓
4. D Rainfall is guaranteed ✓

Radiation frost is most likely on nights that are

1. A Cloudy, windy and humid ✓
2. B Hot with strong convection ✓
3. C Clear, calm and dry ✓
4. D Rainy with high soil temperature ✓

Advection frost is mainly caused by

1. A Movement of a cold air mass into an area ✓
2. B Rapid evaporation from irrigation channels ✓
3. C High soil salinity ✓
4. D Short photoperiod during winter ✓

A practical use of heat unit accumulation in crop management is to predict

1. A Soil pH after fertilizer use ✓
2. B Seed purity percentage ✓
3. C Harvest losses from rodents ✓
4. D Crop growth stages and maturity ✓

Cardinal temperatures for crop growth refer to

1. A Minimum, optimum and maximum temperatures ✓
2. B Morning, noon and evening temperatures ✓
3. C Soil, water and air temperatures ✓
4. D Monthly, seasonal and annual temperatures ✓

Among the following crops, the one with C4 photosynthetic pathway is

1. A Wheat ✓
2. B Maize ✓
3. C Rice ✓
4. D Potato ✓

C4 crops are generally more efficient than C3 crops under

1. A Low light and cold humid conditions ✓
2. B Deep shade with low CO2 ✓
3. C High light and high temperature conditions ✓
4. D Continuous waterlogging ✓

Drought stress during flowering in grain crops most directly reduces yield by affecting

1. A Seed coat colour ✓
2. B Root hair colour ✓
3. C Stem node number only ✓
4. D Pollination and grain set ✓

Waterlogging injures most upland crops primarily because it reduces

1. A Day length above the canopy ✓
2. B Oxygen supply in the root zone ✓
3. C Incoming solar radiation ✓
4. D Atmospheric carbon dioxide ✓

The main monsoon rainfall season in Pakistan normally occurs during

1. A July to September ✓
2. B December to February ✓
3. C March to April only ✓
4. D October to November only ✓

Winter rainfall over northern and western Pakistan is mainly associated with

1. A Southwest monsoon depressions ✓
2. B Sea breezes only ✓
3. C Western disturbances ✓
4. D Tropical cyclones from the Pacific ✓

The Koppen climate classification is based mainly on

1. A Soil texture and pH ✓
2. B Crop yield and fertilizer dose ✓
3. C Wind speed and sunshine only ✓
4. D Temperature and precipitation patterns ✓

An aridity index commonly expresses dryness by comparing precipitation with

1. A Potential evapotranspiration ✓
2. B Soil bulk density ✓
3. C Leaf area duration ✓
4. D Wind direction frequency ✓

A likely agricultural impact of climate change in South Asia is increased risk of

1. A Permanent elimination of all pests ✓
2. B Heat waves and extreme weather events ✓
3. C Uniform rainfall every week ✓
4. D Lower night temperature in all seasons ✓

Elevated atmospheric CO2 generally stimulates photosynthesis more strongly in

1. A C4 crops than C3 crops ✓
2. B CAM plants only ✓
3. C All crops equally without limits ✓
4. D C3 crops than C4 crops ✓

Heat stress at anthesis in wheat commonly causes

1. A Improved grain filling duration ✓
2. B Higher seed germination on the plant ✓
3. C Pollen sterility and shriveled grains ✓
4. D Complete resistance to rust ✓

Chilling injury in warm-season crops occurs at temperatures that are

1. A Low but above freezing ✓
2. B Above optimum by 15 C ✓
3. C Exactly at boiling point ✓
4. D Only below minus 20 C ✓

High relative humidity and prolonged wetness generally favour

1. A Rapid seed drying in storage ✓
2. B Fungal disease development ✓
3. C Lower dew formation ✓
4. D Reduced pathogen survival always ✓

Leaf wetness duration is especially important in forecasting

1. A Soil salinity class ✓
2. B Seed dormancy depth ✓
3. C Plant disease risk ✓
4. D Canal water duty ✓

Agroclimatic zoning groups areas according to similarity in

1. A Farm ownership and land revenue ✓
2. B Seed certification rules ✓
3. C Market price behaviour only ✓
4. D Climate resources and crop production potential ✓

The climate immediately around and within a crop canopy is called

1. A Macroclimate ✓
2. B Microclimate ✓
3. C Paleoclimate ✓
4. D Synoptic climate ✓

Shelterbelts in agricultural fields are used mainly to

1. A Reduce wind speed and wind erosion ✓
2. B Increase hailstorm frequency ✓
3. C Stop all rainfall runoff ✓
4. D Raise soil salinity deliberately ✓

An air temperature inversion near the ground means that temperature

1. A Decreases normally with height ✓
2. B Is equal at all heights ✓
3. C Falls only below the soil surface ✓
4. D Increases with height over the lower layer ✓

Albedo is the fraction of incoming radiation that is

1. A Absorbed by roots ✓
2. B Converted into rainfall ✓
3. C Reflected by a surface ✓
4. D Stored as soil nitrogen ✓

Net radiation over a crop canopy is the balance between

1. A Incoming and outgoing radiation ✓
2. B Rainfall and runoff ✓
3. C Fertilizer input and nutrient removal ✓
4. D Wind speed and air pressure ✓

The Campbell-Stokes recorder is used to measure

1. A Soil moisture tension ✓
2. B Bright sunshine duration ✓
3. C Atmospheric ozone ✓
4. D Canopy temperature only ✓

A pyranometer measures

1. A Rainfall intensity ✓
2. B Wind direction ✓
3. C Global solar radiation ✓
4. D Soil heat flux only ✓

A psychrometer estimates humidity using

1. A Two rain gauges at different heights ✓
2. B A barometer and anemometer ✓
3. C Soil thermometer and tensiometer ✓
4. D Dry-bulb and wet-bulb thermometers ✓

Lines joining places of equal temperature on a weather map are called

1. A Isotherms ✓
2. B Isohyets ✓
3. C Isobars ✓
4. D Isonephs ✓

Lines joining places of equal rainfall are known as

1. A Isotherms ✓
2. B Isohyets ✓
3. C Isobars ✓
4. D Contours ✓

A standard rain gauge measures precipitation as

1. A Volume of clouds above a station ✓
2. B Percentage of humidity in air ✓
3. C Depth of water collected over an area ✓
4. D Speed of falling raindrops ✓

Effective rainfall for crop production means the part of rainfall that

1. A Falls only during nighttime ✓
2. B Evaporates before reaching soil ✓
3. C Runs off the field immediately ✓
4. D Is stored in the root zone and used by crops ✓

A crop weather calendar is prepared to link crop stages with

1. A Normal weather conditions and advisories ✓
2. B Only market arrivals ✓
3. C Only machinery depreciation ✓
4. D Seed lot certification codes ✓

The Bowen ratio in an energy balance study is the ratio of sensible heat flux to

1. A Net rainfall ✓
2. B Latent heat flux ✓
3. C Soil salinity ✓
4. D Canopy albedo ✓

Rabi crops in Pakistan are mainly grown during

1. A peak monsoon only ✓
2. B winter season (roughly Oct/Nov to Apr/May) ✓
3. C continuous summer flooding only ✓
4. D arctic night only ✓

Kharif crops in Pakistan are mainly grown during

1. A deep winter only ✓
2. B summer/monsoon season (roughly Apr/May to Sep/Oct) ✓
3. C permanent snow cover only ✓
4. D polar night ✓

Wheat in Pakistan is primarily a

1. A Kharif-only crop ✓
2. B perennial tree crop ✓
3. C Rabi crop ✓
4. D aquatic weed ✓

Rice in Pakistan is primarily a

1. A Rabi-only cereal ✓
2. B winter vegetable ✓
3. C temperate berry ✓
4. D Kharif crop ✓

Cotton in Pakistan is mainly cultivated as a

1. A Rabi pulse ✓
2. B winter oilseed only ✓
3. C Kharif crop ✓
4. D alpine scrub ✓

The most important climatic factor limiting rainfed crop production in Pakistan is often

1. A constant daily fog nationwide ✓
2. B excess snowfall on plains every week ✓
3. C zero solar radiation ✓
4. D amount and distribution of rainfall ✓

Growing degree days (heat units) are used to

1. A measure soil salinity only ✓
2. B estimate crop development in relation to temperature ✓
3. C count canal outlets ✓
4. D price fertilizers ✓

Photosynthesis in crops generally increases with light up to

1. A infinite darkness ✓
2. B absolute zero temperature ✓
3. C complete flooding forever ✓
4. D a light saturation point ✓

Frost injury is most critical for

1. A desert cactus only ✓
2. B sensitive Rabi crops and horticultural plants at vulnerable stages ✓
3. C mangrove pneumatophores only ✓
4. D deep-sea algae ✓

Heat stress during wheat grain filling in Pakistan can cause

1. A increased grain size always ✓
2. B zero effect on yield ✓
3. C mandatory higher protein always ✓
4. D shriveled grains and yield loss ✓

Monsoon rainfall in Pakistan is associated mainly with

1. A only Mediterranean winter cyclones ✓
2. B summer moisture from the southwest monsoon system ✓
3. C only polar easterlies ✓
4. D only El Niño ending all rain forever ✓

Western disturbances mainly affect Pakistan by bringing

1. A only tropical cyclones in December nationwide ✓
2. B permanent drought every winter ✓
3. C zero cloud cover always ✓
4. D winter/spring rainfall useful for Rabi crops ✓

Evapotranspiration (ET) is the combined loss of water by

1. A evaporation from soil/water surfaces and transpiration from plants ✓
2. B only deep percolation ✓
3. C only runoff to oceans ✓
4. D only canal seepage ✓

Crop water requirement is generally highest when

1. A plants are dormant seeds in cold storage ✓
2. B canopy is full and weather is hot, dry and windy ✓
3. C humidity is 100% with zero radiation ✓
4. D night temperatures are near freezing with closed stomata always ✓

Drought stress reduces yield mainly by

1. A limiting photosynthesis, growth and reproductive success ✓
2. B increasing leaf area indefinitely ✓
3. C eliminating stomata forever ✓
4. D raising soil water to saturation ✓

Lodging in cereals is often promoted by

1. A complete drought only ✓
2. B zero fertilizer ever ✓
3. C underground sowing only ✓
4. D strong winds, heavy rain and excessive nitrogen with weak stems ✓

Photoperiodism refers to plant responses to

1. A day length (light period) ✓
2. B only soil pH ✓
3. C only fertilizer brand ✓
4. D only tractor speed ✓

Short-day plants tend to flower when

1. A days are extremely long always ✓
2. B light is continuous 24 hours necessarily ✓
3. C nights are relatively long (days short) ✓
4. D temperature is the only cue ✓

Relative humidity affects crops because low humidity

1. A increases evaporative demand and can intensify stress ✓
2. B always stops transpiration ✓
3. C eliminates the need for irrigation ✓
4. D raises soil water automatically ✓

Hailstorms damage crops mainly by

1. A mechanical injury to leaves, stems and fruits ✓
2. B increasing soil organic matter ✓
3. C improving grain quality always ✓
4. D cooling roots beneficially only ✓

Climate classification for agriculture helps to

1. A ignore agro-ecology ✓
2. B plant the same variety everywhere mandatorily ✓
3. C match crops and varieties to regional temperature and moisture regimes ✓
4. D ban zoning ✓

Arid zones of Pakistan are characterized by

1. A continuous rainforest canopy ✓
2. B permanent swamp cover ✓
3. C low rainfall and high evaporative demand ✓
4. D glacial ice sheets on plains ✓

Semi-arid barani areas depend critically on

1. A permanent flooding ✓
2. B ocean tides ✓
3. C greenhouse CO2 injection only ✓
4. D timely seasonal rains and moisture conservation ✓

Cloud cover reduces

1. A incoming solar radiation available for photosynthesis ✓
2. B soil nitrogen to zero instantly ✓
3. C root depth mandatorily ✓
4. D genetic diversity ✓

Wind can benefit crops by

1. A always destroying all canopies ✓
2. B eliminating pollination ✓
3. C enhancing CO2 supply and reducing some disease humidity ✓
4. D stopping ET completely ✓

Chilling requirement is important for

1. A tropical rice flowering in Sindh only ✓
2. B date palms needing frost ✓
3. C some temperate fruit trees to break dormancy ✓
4. D sugarcane needing alpine cold ✓

CO2 enrichment can increase photosynthesis but field benefits depend on

1. A CO2 alone guaranteeing infinite yield ✓
2. B water, nutrients and temperature interactions ✓
3. C darkness being sufficient ✓
4. D salinity disappearing automatically ✓

Phenology of a crop means

1. A timing of developmental stages such as flowering and maturity ✓
2. B only soil texture class ✓
3. C only fertilizer grade ✓
4. D only market price ✓

Early sowing of wheat in many Pakistani zones is recommended to

1. A maximize frost kill of seedlings ✓
2. B escape terminal heat at grain filling ✓
3. C ensure monsoon flooding ✓
4. D delay harvest into peak heat deliberately ✓

Microclimate in a crop canopy differs from screen weather because of

1. A shade, humidity and wind modification by vegetation ✓
2. B identical conditions always ✓
3. C no temperature gradients ✓
4. D absence of ET ✓

Flooding injury in non-rice crops is mainly due to

1. A excess oxygen toxicity only ✓
2. B increased mycorrhizae always ✓
3. C oxygen deficiency in the root zone ✓
4. D higher photosynthesis ✓

Temperature optimum for most warm-season Kharif crops is generally

1. A near freezing ✓
2. B identical to alpine scrub ✓
3. C below 5°C continuously ✓
4. D higher than for cool-season Rabi cereals ✓

Climate-smart agriculture aims to

1. A ignore climate risks ✓
2. B increase emissions deliberately ✓
3. C abandon all adaptation ✓
4. D raise productivity while adapting to climate risk and reducing emissions intensity ✓

El Niño / La Niña can influence Pakistan's agriculture by

1. A altering monsoon and drought/flood probabilities ✓
2. B fixing daily weather forever ✓
3. C eliminating seasons ✓
4. D changing soil taxonomy overnight ✓

Dew and light drizzle may help

1. A slightly reduce stress in dry spells but rarely replace irrigation ✓
2. B fully irrigate cotton all season ✓
3. C dissolve salinity permanently ✓
4. D replace canal water entirely ✓

Cardinal temperatures of a crop refer to

1. A only soil color temperatures ✓
2. B minimum, optimum and maximum temperatures for growth ✓
3. C fertilizer melting points ✓
4. D canal water boiling point ✓

Humidity and temperature together influence

1. A only tractor fuel efficiency ✓
2. B only seed coat color ✓
3. C pest and disease outbreaks as well as ET ✓
4. D only GPS accuracy ✓

Agrometeorology is the study of

1. A only stock markets ✓
2. B weather and climate in relation to agriculture ✓
3. C only pure astronomy without Earth ✓
4. D only ocean trenches ✓

Heat wave during cotton flowering/boll formation can

1. A always double lint yield ✓
2. B eliminate pests forever ✓
3. C raise groundwater automatically ✓
4. D increase square/boll shedding and reduce yield ✓

Matching crop calendars to climate means

1. A planting randomly any day ✓
2. B ignoring frost risk ✓
3. C sowing and harvesting in periods with suitable temperature and moisture ✓
4. D sowing only at solar noon mandatorily ✓