Analyzing a Soil Test

OBJECTIVE

Students will be able to analyze a soil test

Students will be able to amend soil according to soil test results

ESSENTIAL QUESTIONS

What is soil?

How do we improve soil health?

Why is soil health important?

MATERIALS NEEDED

Soil testing materials
Soil test results
Amendments
Measuring tape
Scale
Paper cups
Cultivators

PROCEDURE

Introduction:

Review soil knowledge. Ask students, “What is balanced soil? What does it mean to have healthy soil?”

Explain that soil samples were collected from the school garden and were sent to be analyzed. We have the results, and we are going to explore them together and figure out what we need to do to make our garden grow the best food for our school!

Ask students, “how do we know how much we can amend the soil/how much fertilizer we can add? Is there such a thing as too much fertilizer?”

Activity

In small groups, students look over the soil test results. (The ideal levels for each element should be listed on the test. If not, post the ideal levels on the board) In their journals, students respond to the following questions:

Which elements are too high? What can we do to lower levels of certain elements? Which elements are too low? Find relationships between elements (do you see any patterns when one element is high another is low and vice versa?)

Calcium and Boron, Sulfur and Magnesium, Potassium and Calcium

What options are there for addressing these results? Adding compost, lime, cover cropping, irrigation

Wrap Up/Assessment

Explain to students that it is their job to figure out how to make the soil in the garden beds as balanced and heathy as possible. Heathy soil leads to healthier plants and people. Break students into small groups and assign each group a different garden bed. Hand out results from each garden bed. In order to figure out how much of each amendment they are going to need, students must first do the math:

     -Area of bed  

     -Rate per acre of each amendment (usually ton/acre)  

     -There are 43,560 sq feet in an acre  

     -2,000 lbs. in a ton

Using this ratio, students find their amendment measurement:

2000 lbs/ 4,560 sq feet = x/ (your garden’s sq feet)

If lbs. is too large a measurement, convert to ounces using this measurement:

16 oz/1lb = x/(your garden’s boron lbs)

Students present their findings to the class.

Next, students measure the correct amount of each amendment for their bed, in paper cups.

Finally, students go out to the garden and scratch their fertilizer into the soil using cultivators.

Students record their amendments in their journals, and in the garden binder for future students to see what they’ve done.