Test 19 - Consumptive Use and Evapotranspiration

Question 1 ప్రశ్న 1

In irrigation engineering, which description best represents the consumptive use of a crop?

A The total volume released from a reservoir including canal losses B The water consumed mainly through crop transpiration and evaporation from the cropped area, together with the very small amount incorporated into plant tissue C Only the water stored below the permanent wilting point D The total rainfall received over the catchment regardless of crop use

Question 2 ప్రశ్న 2

What does the term evapotranspiration represent?

A Only evaporation from open-water surfaces B Only transpiration through crop leaves C The combined loss of water by evaporation and plant transpiration D The sum of rainfall and irrigation supplied to a field

Question 3 ప్రశ్న 3

Under standard, non-water-stressed crop conditions, how is crop water requirement most closely related to crop evapotranspiration ETc?

A Crop water requirement is generally taken as the amount needed to replace ETc B Crop water requirement is always twice ETc C Crop water requirement is equal only to soil evaporation D Crop water requirement is independent of evapotranspiration

Question 4 ప్రశ్న 4

Why can the net irrigation requirement of a crop be smaller than its seasonal consumptive use?

A Because irrigation water has no relation to evapotranspiration B Because crop transpiration stops whenever rainfall occurs C Because effective rainfall and usable stored soil water can supply part of the crop water requirement D Because canal conveyance losses reduce crop evapotranspiration

Question 5 ప్రశ్న 5

What is meant by effective rainfall in irrigation planning?

A The entire measured rainfall regardless of runoff or deep percolation B The portion of rainfall that is stored or otherwise available to satisfy crop water requirements C Only rainfall occurring at night D Rainfall that falls outside the growing season

Question 6 ప్రశ్న 6

Which climatic combination would generally produce the highest reference evapotranspiration, other factors being comparable?

A Cool, humid, cloudy and calm weather B Hot, dry, sunny and windy weather C Cool, saturated air with no solar radiation D Cold weather with high relative humidity and no wind

Question 7 ప్రశ్న 7

Which statement best describes the effect of soil-water shortage on actual crop evapotranspiration?

A Actual evapotranspiration may fall below the standard crop evapotranspiration because water stress restricts transpiration B Actual evapotranspiration must increase whenever the soil becomes dry C Soil-water availability cannot influence transpiration D Actual evapotranspiration always remains equal to reference evapotranspiration

Question 8 ప్రశ్న 8

At introductory irrigation-design level, which relation is used to estimate crop evapotranspiration from reference evapotranspiration?

A ETc = ETo/Kc B ETc = Kc × ETo C ETc = Kc + ETo D ETc = Kc - ETo

Question 9 ప్రశ్న 9

Reference evapotranspiration is 5.0 mm/day and the crop coefficient is 1.10. What is the crop evapotranspiration under standard conditions?

A 4.5 mm/day B 5.0 mm/day C 5.5 mm/day D 6.1 mm/day

Question 10 ప్రశ్న 10

A crop has ETc = 6.0 mm/day when ETo = 5.0 mm/day. What is the crop coefficient?

A 0.83 B 1.00 C 1.20 D 1.50

Question 11 ప్రశ్న 11

Why does the crop coefficient Kc normally vary during the growing season?

A Because crop canopy development, ground cover, crop height and physiological activity change with growth stage B Because hydraulic conductivity of the aquifer changes every day C Because rainfall intensity is mathematically part of Kc D Because reference evapotranspiration is always constant

Question 12 ప్రశ్న 12

A crop has ETo = 5.0 mm/day and Kc = 1.10 for a 30-day period. What is the crop evapotranspiration during that period?

A 110 mm B 150 mm C 165 mm D 330 mm

Question 13 ప్రశ్న 13

A crop consumes 450 mm of water by evapotranspiration during a 120-day growing season. What is the average seasonal consumptive-use rate?

A 2.50 mm/day B 3.00 mm/day C 3.75 mm/day D 5.40 mm/day

Question 14 ప్రశ్న 14

A crop has a seasonal ETc of 500 mm. Gross rainfall is 120 mm, of which 75% is effective. Neglecting soil-water and groundwater contributions, what is the net irrigation requirement?

A 90 mm B 380 mm C 410 mm D 500 mm

Question 15 ప్రశ్న 15

A crop requires 600 mm of seasonal evapotranspiration. Effective rainfall supplies 180 mm and usable soil-water storage contributes another 40 mm. Neglecting other contributions, what is the net irrigation requirement?

A 340 mm B 380 mm C 420 mm D 780 mm

Question 16 ప్రశ్న 16

A field has a net seasonal irrigation requirement of 400 mm. If field application efficiency is 80%, what gross depth must be delivered for field application?

A 320 mm B 400 mm C 480 mm D 500 mm

Question 17 ప్రశ్న 17

A seasonal crop evapotranspiration depth of 500 mm occurs over an irrigated area of 25 hectares. What volume of water does this ET depth represent?

A 12,500 m³ B 50,000 m³ C 125,000 m³ D 1,250,000 m³

Question 18 ప్రశ్న 18

Two crops are grown side by side under the same weather conditions, so they have the same ETo, but Crop X has Kc = 1.15 and Crop Y has Kc = 0.75. Which statement is correct under standard conditions?

A Crop Y has the larger ETc B Both crops must have identical ETc because ETo is identical C Crop X has the larger ETc because its crop coefficient is higher D Kc cannot influence crop water use

Question 19 ప్రశ్న 19

The same well-watered crop at the same growth stage is grown at two locations, one hot, dry and windy and the other cool and humid. Which quantity primarily captures the difference in climatic evaporative demand in the Kc-ETo approach?

A Reference evapotranspiration ETo B Permanent wilting point C Specific yield D Canal duty

Question 20 ప్రశ్న 20

Which statement best describes the influence of soil properties on crop consumptive use and irrigation management?

A Soil texture and rooting conditions affect water storage and availability, which can influence actual ET under water stress and strongly affect irrigation frequency B Soil properties directly determine solar radiation C Soil texture is the sole factor controlling reference evapotranspiration D A sandy soil and clay soil must always have identical irrigation schedules if the crop is the same

Question 21 ప్రశ్న 21

Why is effective rainfall usually less than gross rainfall when estimating irrigation requirement?

A Because only nighttime rainfall can be used by crops B Because part of gross rainfall may be lost as runoff, deep percolation or other water not stored usefully in the crop root zone C Because rainfall does not enter the soil D Because effective rainfall excludes all infiltration

Question 22 ప్రశ్న 22

A crop has seasonal ETc = 500 mm, effective rainfall = 150 mm and a usable contribution of 50 mm from soil-water storage. Neglecting all other sources and requirements, what irrigation depth must be supplied net to the root zone?

A 250 mm B 300 mm C 350 mm D 400 mm

Question 23 ప్రశ్న 23

Which statement correctly distinguishes crop consumptive use from gross irrigation-water supply?

A Consumptive use includes all canal seepage and operational losses B Gross irrigation supply can exceed consumptive use because it may have to cover field and conveyance losses in addition to the net crop deficit C Gross irrigation supply is always smaller than effective rainfall D The two quantities must always be numerically identical

Question 24 ప్రశ్న 24

A crop has the following simplified seasonal stages: 20 days with ETo = 4 mm/day and Kc = 0.50; 30 days with ETo = 5 mm/day and Kc = 0.80; 40 days with ETo = 6 mm/day and Kc = 1.15; and 30 days with ETo = 4 mm/day and Kc = 0.70. What is the total seasonal ETc?

A 420 mm B 480 mm C 520 mm D 600 mm

Question 25 ప్రశ్న 25

Consider the following statements: I. Consumptive use is dominated by evapotranspiration rather than conveyance losses. II. Effective rainfall can reduce irrigation requirement. III. Under the crop-coefficient approach, ETc = KcETo. IV. A crop under severe soil-water stress may have actual evapotranspiration below its standard ETc. Which option is correct?

A I and II only B I, II and III only C II, III and IV only D I, II, III and IV

Question 26 ప్రశ్న 26

A crop has seasonal ETc = 520 mm. Effective rainfall contributes 170 mm and usable initial soil-water storage contributes 30 mm. If field application efficiency is 70% and no other requirements are included, what gross irrigation depth should be supplied at the field?

A 320 mm B 400 mm C 457 mm D 743 mm

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