School Improvement in Maryland
the Copper Basin Problem  

Teacher Section

Chemicals in the Soil
Lesson 3:

Objective:

  • To measure the effects of soil chemistry on the growth of plants.

    • Materials:

  • simulated Copper Basin soil
  • potting soil
  • local soil
  • compost or humus
  • seeds
  • small cups
  • planting trays
  • soil tests: pH, Phosphorus, Nitrogen, Potassium, Sulfide, Copper

    • My classes met this objective in two ways. First, they developed an experiment in which seeds were grown in different soil types and in simulated 'Copper Basin' soil. Next, the students also compared the chemical content of the soils they selected to see if there was some factor in Copper Basin soil that prohibited revegetation.

    Procedure:

    1. The students developed a simple experiment to test soil type on the germination of seeds. A sample experiment can be found in the student section. Through research, they discovered the components of the soil in the Copper Basin. I worked with the chemistry teacher to develop the soil. Results of the experiment were recorded daily and analyzed after several days. Following is a recipe for making 'simulated soil' This does not match mine soil exactly, but it does provide the most significant features of the mine soil, especially those that affect plant growth.
      (Copper sulfate is a potent herbicide.)

      • Mix the following chemicals in 1 liter of distilled water

        CuSO4 2.0 mg
        FeSO4 138.0 mg
        MnSO4 · 7H20 30.0 mg
        CaHPO4 7.0 mg
        K2SO4 41.0 mg
        MgSO4 · 7H2O 200.0 mg
        Ca(OH)2 278.0 mg

      • Add 51 mL of concentrated sulfuric acid.
      • Using calcium hydroxide or sulfuric acid, adjust the pH to between 4 and 5.
      • Pour this solution into 1kg of damp sand, mix and allow to dry for several days.

    2. They used test kits for soil nutrients and contaminants.

    3. The results of both the germination experiments and the soil chemical tests were compared. Some students hypothesized possible solutions to the problem of revegetation and designed investigations to test their own ideas.

    4. These soil labs also helped students to analyze the effect of local reclamation projects on previously mined areas. Discussion followed that compared the two situations. Our electronic link with other schools enabled us to compare our own test results to those from students in other geographic regions.
       
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