All the methods of calculating crop evapotranspiration involve which one of the following relationships? (where Kc is crop coefficient, ETo is potential evapotranspiration and ETc is evapotranspiration of a specific crop.)
- AETc = 2 Kc ETo
- BETc = Kc EToCorrect
- CETc = 4 Kc ETo
- DETc = Kc / ETo
Solution
Concept
Crop coefficient approach
Formula
ETc = Kc · ETo
Step-by-step solution
1. Crop evapotranspiration is the reference (potential) evapotranspiration multiplied by the crop coefficient.
Explanation
The crop coefficient converts the reference evapotranspiration to that of a particular crop at a given growth stage.
Why the other options are wrong
The other relations have extra factors or a ratio that is not used.
Shortcut
ETc = Kc × ETo.
Common mistake
Dividing instead of multiplying.
Correct answer: B) ETc = Kc ETo