Module 3:  Discover the effect of fertilizer on plant growth.  Back to the top.

Introduction:  This lab is determine the effect of fertilizer on plant growth.  Plants act as a filter by taking up polluting nutrients in the environment.  This means that plants can be used in areas where run-off is a problem to filter excess nutrients out of the run-off before it can reach a waterway.  This lab can be used with chemical or organic fertilizer.  The data table for recording data from an experiment using one fertilizer is here.  The data table for comparing the effects of two types of fertilizers is here.

Materials:  For a class of 30, groups of three.  Please adjust according to class size.

1.            20 Plastic planter containers with plants, or a mark off small areas   

   outside in the grass.

2.    Soil.  Examples include sand, peat moss, topsoil, clay, potting soil,

         compost, or mixtures of the above.

3.    Water.

            4.      Containers to hold the water.

            5.      Ammonium nitrate fertilizer.

            6.      Milorganite (optional)

Questions to ask, discuss, and record before beginning experiment:

1.   What kind of fertilizer is ammonium nitrate?
2.   What kind of fertilizer is milorganite?
3.   Will the experiment compare a chemical fertilizer to a control, an organic  

        fertilizer to a control, or a chemical and organic fertilizer to a control?  It is

        important to know the kind of question you are trying to answer before starting

        the experiment.

Procedure:

1. Place the manufactures recommended amount of fertilizer in the container marked test.  Continue to add the recommended amount of fertilizer over the time interval specified in the manufacturer’s instructions.  (Optional)  If comparing milorganite to ammonia nitrate each group will need three plants.  One for each fertilizer and one as a control. If comparing the effect of fertilizer on grass growth outside, be sure to label the areas to be used and ensure that fertilizer will not contaminate the control area.
2. Record comparisons of test plants and control plants daily or weekly.  Record times that plants are fertilized and watered, and how much of each is given.  Be sure to water all plants equally if kept indoors in containers. 
3. Measure the amount of growth both vertically and horizontally with a ruler.  Also, record any observations made regarding the color of the plants.  Do they appear to be very green, somewhat green, yellowish green, yellow, or brown?
4. Continue making recordings for as long as possible to ensure enough data is obtained to analyze.

Questions to ask, discuss, and record after experiment:

1.         Discuss what was learned from the experiment.  Did everyone have the same

            results/ observations?  How did your hypothesis compare with the actually   

            result?

2.                  What effect, if any, did the fertilizer have on plant growth?  Compare the

            growth of the control plants to the test plants.

3.                  Make a graph comparing time to the growth of the fertilized plants and to the controls.

4.                  Discuss different ways the experiment could be carried out and how you think the results might differ.

Data Table for Module 3:  For use with one fertilizer type.  Back.

Data Table 2 for Module 3:  For use with two fertilizer types.  Back.