37.7. Effective Rainfall (ER)

Try these first

1. 1.

   Define Effective Rainfall.

   Hint

   Think about how rainfall impacts crop growth.

2. 2.

   What does the USDA method utilize for estimating ER?

   Hint

   Consider what kind of data is typically collected over time.

3. 3.

   What does Effective Rainfall refer to?

   • Total rainfall
   • Usable rainfall for crops
   • Rainfall lost to runoff

   Hint

   Which option highlights the beneficial part of rain?

4. 4.

   True or False: All rainfall is effective for crops.

   • True
   • False

   Hint

   Consider the losses that occur when it rains.

5. 5.

   A farmer observed 150 mm of rainfall but recorded 40 mm of runoff and 20 mm lost to evaporation before reaching the soil. Calculate the effective rainfall.

   Hint

   Subtract all losses from total rainfall.

6. 6.

   Discuss the advantages and possible limitations of the USDA method versus the Soil Moisture Balance Method in estimating effective rainfall.

   Hint

   Think about the trade-offs in ease of use versus detail.