Agricultural Meteorology and Climate-Crop Relations MCQs 2026

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

1. ABarometer✓
2. BHygrometer✓
3. CAnemometer✓
4. DPyrheliometer✓

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

1. AAgricultural meteorology✓
2. BAgricultural economics✓
3. CSoil taxonomy✓
4. DPlant pathology✓

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

1. AGeothermal heat✓
2. BSolar radiation✓
3. CSoil respiration✓
4. DLunar radiation✓

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

1. ANet rainfall✓
2. BLatent heat flux✓
3. CSoil salinity✓
4. DCanopy albedo✓

A crop weather calendar is prepared to link crop stages with

1. ANormal weather conditions and advisories✓
2. BOnly market arrivals✓
3. COnly machinery depreciation✓
4. DSeed lot certification codes✓

Effective rainfall for crop production means the part of rainfall that

1. AFalls only during nighttime✓
2. BEvaporates before reaching soil✓
3. CRuns off the field immediately✓
4. DIs stored in the root zone and used by crops✓

A standard rain gauge measures precipitation as

1. AVolume of clouds above a station✓
2. BPercentage of humidity in air✓
3. CDepth of water collected over an area✓
4. DSpeed of falling raindrops✓

Lines joining places of equal rainfall are known as

1. AIsotherms✓
2. BIsohyets✓
3. CIsobars✓
4. DContours✓

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

1. AIsotherms✓
2. BIsohyets✓
3. CIsobars✓
4. DIsonephs✓

A psychrometer estimates humidity using

1. ATwo rain gauges at different heights✓
2. BA barometer and anemometer✓
3. CSoil thermometer and tensiometer✓
4. DDry-bulb and wet-bulb thermometers✓

A pyranometer measures

1. ARainfall intensity✓
2. BWind direction✓
3. CGlobal solar radiation✓
4. DSoil heat flux only✓

The Campbell-Stokes recorder is used to measure

1. ASoil moisture tension✓
2. BBright sunshine duration✓
3. CAtmospheric ozone✓
4. DCanopy temperature only✓

Net radiation over a crop canopy is the balance between

1. AIncoming and outgoing radiation✓
2. BRainfall and runoff✓
3. CFertilizer input and nutrient removal✓
4. DWind speed and air pressure✓

Albedo is the fraction of incoming radiation that is

1. AAbsorbed by roots✓
2. BConverted into rainfall✓
3. CReflected by a surface✓
4. DStored as soil nitrogen✓

An air temperature inversion near the ground means that temperature

1. ADecreases normally with height✓
2. BIs equal at all heights✓
3. CFalls only below the soil surface✓
4. DIncreases with height over the lower layer✓

Shelterbelts in agricultural fields are used mainly to

1. AReduce wind speed and wind erosion✓
2. BIncrease hailstorm frequency✓
3. CStop all rainfall runoff✓
4. DRaise soil salinity deliberately✓

The climate immediately around and within a crop canopy is called

1. AMacroclimate✓
2. BMicroclimate✓
3. CPaleoclimate✓
4. DSynoptic climate✓

Agroclimatic zoning groups areas according to similarity in

1. AFarm ownership and land revenue✓
2. BSeed certification rules✓
3. CMarket price behaviour only✓
4. DClimate resources and crop production potential✓

Leaf wetness duration is especially important in forecasting

1. ASoil salinity class✓
2. BSeed dormancy depth✓
3. CPlant disease risk✓
4. DCanal water duty✓

High relative humidity and prolonged wetness generally favour

1. ARapid seed drying in storage✓
2. BFungal disease development✓
3. CLower dew formation✓
4. DReduced pathogen survival always✓

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

1. ALow but above freezing✓
2. BAbove optimum by 15 C✓
3. CExactly at boiling point✓
4. DOnly below minus 20 C✓

Heat stress at anthesis in wheat commonly causes

1. AImproved grain filling duration✓
2. BHigher seed germination on the plant✓
3. CPollen sterility and shriveled grains✓
4. DComplete resistance to rust✓

Elevated atmospheric CO2 generally stimulates photosynthesis more strongly in

1. AC4 crops than C3 crops✓
2. BCAM plants only✓
3. CAll crops equally without limits✓
4. DC3 crops than C4 crops✓

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

1. APermanent elimination of all pests✓
2. BHeat waves and extreme weather events✓
3. CUniform rainfall every week✓
4. DLower night temperature in all seasons✓

An aridity index commonly expresses dryness by comparing precipitation with

1. APotential evapotranspiration✓
2. BSoil bulk density✓
3. CLeaf area duration✓
4. DWind direction frequency✓

The Koppen climate classification is based mainly on

1. ASoil texture and pH✓
2. BCrop yield and fertilizer dose✓
3. CWind speed and sunshine only✓
4. DTemperature and precipitation patterns✓

Winter rainfall over northern and western Pakistan is mainly associated with

1. ASouthwest monsoon depressions✓
2. BSea breezes only✓
3. CWestern disturbances✓
4. DTropical cyclones from the Pacific✓

The main monsoon rainfall season in Pakistan normally occurs during

1. AJuly to September✓
2. BDecember to February✓
3. CMarch to April only✓
4. DOctober to November only✓

Waterlogging injures most upland crops primarily because it reduces

1. ADay length above the canopy✓
2. BOxygen supply in the root zone✓
3. CIncoming solar radiation✓
4. DAtmospheric carbon dioxide✓

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

1. ASeed coat colour✓
2. BRoot hair colour✓
3. CStem node number only✓
4. DPollination and grain set✓

C4 crops are generally more efficient than C3 crops under

1. ALow light and cold humid conditions✓
2. BDeep shade with low CO2✓
3. CHigh light and high temperature conditions✓
4. DContinuous waterlogging✓

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

1. AWheat✓
2. BMaize✓
3. CRice✓
4. DPotato✓

Cardinal temperatures for crop growth refer to

1. AMinimum, optimum and maximum temperatures✓
2. BMorning, noon and evening temperatures✓
3. CSoil, water and air temperatures✓
4. DMonthly, seasonal and annual temperatures✓

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

1. ASoil pH after fertilizer use✓
2. BSeed purity percentage✓
3. CHarvest losses from rodents✓
4. DCrop growth stages and maturity✓

Advection frost is mainly caused by

1. AMovement of a cold air mass into an area✓
2. BRapid evaporation from irrigation channels✓
3. CHigh soil salinity✓
4. DShort photoperiod during winter✓

Radiation frost is most likely on nights that are

1. ACloudy, windy and humid✓
2. BHot with strong convection✓
3. CClear, calm and dry✓
4. DRainy with high soil temperature✓

Dew point is the temperature at which air becomes saturated and

1. AWind speed becomes zero✓
2. BCondensation begins✓
3. CPhotosynthesis stops✓
4. DRainfall is guaranteed✓

Class A pan observations are primarily used to estimate

1. ASoil texture class✓
2. BAtmospheric nitrogen✓
3. CEvaporation demand✓
4. DLeaf chlorophyll content✓

A lysimeter is mainly used in agrometeorology to measure

1. AAtmospheric pressure✓
2. BWind direction✓
3. CCloud type✓
4. DActual evapotranspiration✓

The crop coefficient Kc is used in the equation

1. AYield = Kc x seed rate✓
2. BETc = Kc x ETo✓
3. CGDD = Kc x rainfall✓
4. DLAI = Kc x temperature✓

The FAO Penman-Monteith method is widely used to estimate

1. AReference evapotranspiration✓
2. BSoil organic carbon✓
3. CLeaf area index directly✓
4. DCrop harvest index✓

Evapotranspiration from a cropped field includes

1. ARunoff and deep percolation✓
2. BPhotosynthesis and respiration✓
3. CRainfall and dew only✓
4. DSoil evaporation and plant transpiration✓

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

1. APhotolysis✓
2. BVernalization✓
3. CSenescence✓
4. DDormancy breaking by scarification✓

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

1. ALonger than its critical photoperiod✓
2. BExactly 24 hours✓
3. CShorter than its critical photoperiod✓
4. DIndependent of darkness duration✓

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

1. APhotoperiodism✓
2. BVernalization✓
3. CThermotropism✓
4. DHygroscopy✓

Base temperature in crop phenology means the temperature below which

1. APhotosynthesis is always maximum✓
2. BEvaporation becomes zero✓
3. CCrop development is assumed to be negligible✓
4. DRespiration is permanently stopped✓

Growing degree days for a crop are commonly computed from

1. AMaximum temperature minus relative humidity✓
2. BRainfall divided by sunshine hours✓
3. CWind speed multiplied by vapour pressure✓
4. DMean daily temperature minus base temperature✓

The average environmental lapse rate in the lower atmosphere is approximately

1. A6.5 C per km✓
2. B1.0 C per km✓
3. C15.0 C per km✓
4. D0.65 C per 100 km✓

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

1. ACollect rainfall without splash losses✓
2. BShield thermometers from direct radiation while allowing ventilation✓
3. CMeasure wind speed near crop canopy✓
4. DStore soil samples at constant temperature✓

Relative humidity in the field is most directly measured with a

1. ARain gauge✓
2. BAnemometer✓
3. CSoil thermometer✓
4. DHygrometer✓

Rabi crops in Pakistan are mainly grown during

1. Apeak monsoon only✓
2. Bwinter season (roughly Oct/Nov to Apr/May)✓
3. Ccontinuous summer flooding only✓
4. Darctic night only✓

Kharif crops in Pakistan are mainly grown during

1. Adeep winter only✓
2. Bsummer/monsoon season (roughly Apr/May to Sep/Oct)✓
3. Cpermanent snow cover only✓
4. Dpolar night✓

Wheat in Pakistan is primarily a

1. AKharif-only crop✓
2. Bperennial tree crop✓
3. CRabi crop✓
4. Daquatic weed✓

Rice in Pakistan is primarily a

1. ARabi-only cereal✓
2. Bwinter vegetable✓
3. Ctemperate berry✓
4. DKharif crop✓

Cotton in Pakistan is mainly cultivated as a

1. ARabi pulse✓
2. Bwinter oilseed only✓
3. CKharif crop✓
4. Dalpine scrub✓

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

1. Aconstant daily fog nationwide✓
2. Bexcess snowfall on plains every week✓
3. Czero solar radiation✓
4. Damount and distribution of rainfall✓

Growing degree days (heat units) are used to

1. Ameasure soil salinity only✓
2. Bestimate crop development in relation to temperature✓
3. Ccount canal outlets✓
4. Dprice fertilizers✓

Photosynthesis in crops generally increases with light up to

1. Ainfinite darkness✓
2. Babsolute zero temperature✓
3. Ccomplete flooding forever✓
4. Da light saturation point✓

Frost injury is most critical for

1. Adesert cactus only✓
2. Bsensitive Rabi crops and horticultural plants at vulnerable stages✓
3. Cmangrove pneumatophores only✓
4. Ddeep-sea algae✓

Heat stress during wheat grain filling in Pakistan can cause

1. Aincreased grain size always✓
2. Bzero effect on yield✓
3. Cmandatory higher protein always✓
4. Dshriveled grains and yield loss✓

Monsoon rainfall in Pakistan is associated mainly with

1. Aonly Mediterranean winter cyclones✓
2. Bsummer moisture from the southwest monsoon system✓
3. Conly polar easterlies✓
4. Donly El Niño ending all rain forever✓

Western disturbances mainly affect Pakistan by bringing

1. Aonly tropical cyclones in December nationwide✓
2. Bpermanent drought every winter✓
3. Czero cloud cover always✓
4. Dwinter/spring rainfall useful for Rabi crops✓

Evapotranspiration (ET) is the combined loss of water by

1. Aevaporation from soil/water surfaces and transpiration from plants✓
2. Bonly deep percolation✓
3. Conly runoff to oceans✓
4. Donly canal seepage✓

Crop water requirement is generally highest when

1. Aplants are dormant seeds in cold storage✓
2. Bcanopy is full and weather is hot, dry and windy✓
3. Chumidity is 100% with zero radiation✓
4. Dnight temperatures are near freezing with closed stomata always✓

Drought stress reduces yield mainly by

1. Alimiting photosynthesis, growth and reproductive success✓
2. Bincreasing leaf area indefinitely✓
3. Celiminating stomata forever✓
4. Draising soil water to saturation✓

Lodging in cereals is often promoted by

1. Acomplete drought only✓
2. Bzero fertilizer ever✓
3. Cunderground sowing only✓
4. Dstrong winds, heavy rain and excessive nitrogen with weak stems✓

Photoperiodism refers to plant responses to

1. Aday length (light period)✓
2. Bonly soil pH✓
3. Conly fertilizer brand✓
4. Donly tractor speed✓

Short-day plants tend to flower when

1. Adays are extremely long always✓
2. Blight is continuous 24 hours necessarily✓
3. Cnights are relatively long (days short)✓
4. Dtemperature is the only cue✓

Relative humidity affects crops because low humidity

1. Aincreases evaporative demand and can intensify stress✓
2. Balways stops transpiration✓
3. Celiminates the need for irrigation✓
4. Draises soil water automatically✓

Hailstorms damage crops mainly by

1. Amechanical injury to leaves, stems and fruits✓
2. Bincreasing soil organic matter✓
3. Cimproving grain quality always✓
4. Dcooling roots beneficially only✓

Climate classification for agriculture helps to

1. Aignore agro-ecology✓
2. Bplant the same variety everywhere mandatorily✓
3. Cmatch crops and varieties to regional temperature and moisture regimes✓
4. Dban zoning✓

Arid zones of Pakistan are characterized by

1. Acontinuous rainforest canopy✓
2. Bpermanent swamp cover✓
3. Clow rainfall and high evaporative demand✓
4. Dglacial ice sheets on plains✓

Semi-arid barani areas depend critically on

1. Apermanent flooding✓
2. Bocean tides✓
3. Cgreenhouse CO2 injection only✓
4. Dtimely seasonal rains and moisture conservation✓

Cloud cover reduces

1. Aincoming solar radiation available for photosynthesis✓
2. Bsoil nitrogen to zero instantly✓
3. Croot depth mandatorily✓
4. Dgenetic diversity✓

Wind can benefit crops by

1. Aalways destroying all canopies✓
2. Beliminating pollination✓
3. Cenhancing CO2 supply and reducing some disease humidity✓
4. Dstopping ET completely✓

Chilling requirement is important for

1. Atropical rice flowering in Sindh only✓
2. Bdate palms needing frost✓
3. Csome temperate fruit trees to break dormancy✓
4. Dsugarcane needing alpine cold✓

CO2 enrichment can increase photosynthesis but field benefits depend on

1. ACO2 alone guaranteeing infinite yield✓
2. Bwater, nutrients and temperature interactions✓
3. Cdarkness being sufficient✓
4. Dsalinity disappearing automatically✓

Phenology of a crop means

1. Atiming of developmental stages such as flowering and maturity✓
2. Bonly soil texture class✓
3. Conly fertilizer grade✓
4. Donly market price✓

Early sowing of wheat in many Pakistani zones is recommended to

1. Amaximize frost kill of seedlings✓
2. Bescape terminal heat at grain filling✓
3. Censure monsoon flooding✓
4. Ddelay harvest into peak heat deliberately✓

Microclimate in a crop canopy differs from screen weather because of

1. Ashade, humidity and wind modification by vegetation✓
2. Bidentical conditions always✓
3. Cno temperature gradients✓
4. Dabsence of ET✓

Flooding injury in non-rice crops is mainly due to

1. Aexcess oxygen toxicity only✓
2. Bincreased mycorrhizae always✓
3. Coxygen deficiency in the root zone✓
4. Dhigher photosynthesis✓

Temperature optimum for most warm-season Kharif crops is generally

1. Anear freezing✓
2. Bidentical to alpine scrub✓
3. Cbelow 5°C continuously✓
4. Dhigher than for cool-season Rabi cereals✓

Climate-smart agriculture aims to

1. Aignore climate risks✓
2. Bincrease emissions deliberately✓
3. Cabandon all adaptation✓
4. Draise productivity while adapting to climate risk and reducing emissions intensity✓

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

1. Aaltering monsoon and drought/flood probabilities✓
2. Bfixing daily weather forever✓
3. Celiminating seasons✓
4. Dchanging soil taxonomy overnight✓

Dew and light drizzle may help

1. Aslightly reduce stress in dry spells but rarely replace irrigation✓
2. Bfully irrigate cotton all season✓
3. Cdissolve salinity permanently✓
4. Dreplace canal water entirely✓

Cardinal temperatures of a crop refer to

1. Aonly soil color temperatures✓
2. Bminimum, optimum and maximum temperatures for growth✓
3. Cfertilizer melting points✓
4. Dcanal water boiling point✓

Humidity and temperature together influence

1. Aonly tractor fuel efficiency✓
2. Bonly seed coat color✓
3. Cpest and disease outbreaks as well as ET✓
4. Donly GPS accuracy✓

Agrometeorology is the study of

1. Aonly stock markets✓
2. Bweather and climate in relation to agriculture✓
3. Conly pure astronomy without Earth✓
4. Donly ocean trenches✓

Heat wave during cotton flowering/boll formation can

1. Aalways double lint yield✓
2. Beliminate pests forever✓
3. Craise groundwater automatically✓
4. Dincrease square/boll shedding and reduce yield✓

Matching crop calendars to climate means

1. Aplanting randomly any day✓
2. Bignoring frost risk✓
3. Csowing and harvesting in periods with suitable temperature and moisture✓
4. Dsowing only at solar noon mandatorily✓