6.1. Direct Methods

Try these first

1. 1.

   What is evapotranspiration?

   Hint

   Think of both plants and soil losing water.

2. 2.

   What is a lysimeter used for?

   Hint

   It's an important tool in studies of plant water usage.

3. 3.

   What is the main purpose of measuring evapotranspiration?

   • To track photosynthesis
   • To assess water loss
   • To measure plant growth

   Hint

   Consider why managing water usage is critical in agricultural contexts.

4. 4.

   True or False: Lysimeters are solely used for measuring soil moisture.

   • True
   • False

   Hint

   Think about what a lysimeter captures in its measurements.

5. 5.

   Design an experiment using a lysimeter to measure the effect of different irrigation levels on plant growth and water loss over two months.

   Hint

   Consider how to control irrigation, weather variability, and measurement intervals.

6. 6.

   Using provided data, calculate the yearly evapotranspiration for a square plot using field water balance method that received 600 mm of irrigation and lost 30% of its moisture content to drainage.

   Hint

   Start with total irrigation and adjust for drainage losses.