Teaching Organic Farming and Gardening

Irrigation

24 | Unit 1.5

Assessment Questions Key

Assessment Questions Key

1. Describe four functions of water in an
   agroecosystem.

• plant support/turgidity

• nutrient transport (soil solution)

• plant cooling through transpiration

• plant nutrient (photosynthesis)

• soil moisture for soil organisms

2. What is soil saturation?

When water is filling all the available pore

spaces in a given soil

3. What is field capacity?

A   soil    is  at  field   capacity    when    the free    water/

gravitational water drains from a saturated soil

4. What is the level of soil moisture at which
   most crop plants require additional water?
   50% of field capacity

5) Describe two ways that agriculturists

determine the need for irrigation.

•    Qualitative:   Measuring   for relative    

percentages of field capacity in the root zone

of the crop

•    Quantitative:  Determining the 

evapotransporation rate of a given site and

systematically replacing the amount of water

lost each week through calibrated water

delivery systems

6) Number the following stages of crop

developmental in terms of their sensitivity to

drought/water stress (1 being most sensitive

and 4 being least sensitive):

1. Flowering


2. Yield formation/fruit set


3. Early vegetative growth


4. Fruit ripening