41.8. Soil-Water-Plant Relationships

Try these first

1. 1.

   Define Root Zone.

   Hint

   Think of where plants grow underground.

2. 2.

   What does Management Allowable Depletion (MAD) refer to?

   Hint

   Consider how dry the soil should get before watering.

3. 3.

   What does the acronym MAD stand for in relation to irrigation?

   • Management Allowable Depletion
   • Maximum Available Depletion
   • Management Allowance of Drainage

   Hint

   Focus on the management aspect of watering.

4. 4.

   True or False: Water Use Efficiency is the ratio of crop yield to water used.

   • True
   • False

   Hint

   Remember what WUE measures.

5. 5.

   A farmer has a crop that uses 500 m³ of water and yields 10,000 kg. Calculate the WUE. If the MAD is set at 20%, how much water can be depleted from an available 250 mm of water before irrigating?

   Hint

   Calculate WUE by dividing yield by water used.

6. 6.

   Given a soil moisture level of 80% of field capacity, determine the allowable depletion level if the total available water is 200 mm and the MAD is 30%. How would this affect irrigation scheduling?

   Hint

   Think about how much water the soil can afford to lose.