43.2.4. Measurement and Estimation of Consumptive Use

Try these first

1. 1.

   What is the lysimeter method used for?

   Hint

   Think about how we measure water loss.

2. 2.

   What does CU represent in the Blaney-Criddle equation?

   Hint

   Think about the overall water used by crops.

3. 3.

   What does the lysimeter method measure?

   • Soil moisture levels
   • Percolation and evapotranspiration
   • Crop yield

   Hint

   Consider what is relevant to water usage.

4. 4.

   True or False: Effective rainfall is the amount of rain that directly runs off the surface.

   • True
   • False

   Hint

   Focus on what effective rainfall implies.

5. 5.

   Using the Penman method, calculate the evapotranspiration for a location with radiation of 20 MJ/m²/day, temperature 30°C, humidity 70%, and wind speed 4 m/s, considering parameters for calculating the Penman equation.

   Hint

   Review the Penman equation components carefully before calculating.

6. 6.

   Assess the impact of using the Thornthwaite method for a farmer in a region with high humidity levels and provide an argument on its effectiveness versus the Penman method in this context.

   Hint

   Consider how humidity affects water use and crop needs.