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GATE 2022 CE (CE2) – Question 20

Irrigation · Irrigation systems and methods, crop water requirements · 1 mark · Multiple choice

In a certain month, the reference crop evapotranspiration at a location is 6 mm/day. If the crop coefficient and soil coefficient are 1.2 and 0.8, respectively, the actual evapotranspiration in mm/day is

  1. 5.76
  2. 7.20
  3. 6.80
  4. 8.00

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Show answer and explanation

Correct answer: (A) 5.76

Explanation

Actual crop evapotranspiration includes both the crop coefficient and the soil stress coefficient: $ET_a=K_sK_cET_0$.

Thus $ET_a=0.8(1.2)(6)=\mathbf{5.76}$ mm/day, **A**. Omitting soil stress would instead give 7.2 mm/day.