Teaching sequence

Work through this resource material in the following sequence (NOTE: This lesson could be conducted over 2 sessions):

5-10 minutes

Tune In: Soil and farming

25-55 minutes

Find Out: Improving soil health with compost

25-55 minutes

Take Action: What soil do plants like best?

5 minutes

Reflection

Tune In: Soil and farming

Step 1

Begin this lesson by setting the scene for students:

Ask students to put on their soil scientist lab coats. Today we will be taking a deeper dive into what’s under our feet and how what’s underground impacts us.

Share the following image and invite students to describe what they see in this image:

Through your discussion, lead students to the idea that this is a farm that is growing barley, a type of grain. You can see that the soil has been shaped into long grooves and that the young barley plants are growing in the grooves. The grooves help protect the young plants and also will collect the moisture that the plants need.

Note: This is an example of intensive farming where large land areas are used to grow one crop (monoculture). In regenerative agriculture, farmers follow the principle that monocultures do not happen in nature, so in attempting to mimic a more natural approach to farming, they try to grow a diverse range of crops.

Step 3

Now share this image and invite students to share what they see:

Through your discussion, explain to students that in this image, we see a farmer checking the soil. Farmers need to have a good understanding of soil (like soil scientists) if they want to grow healthy plants. When they take a close look at the soil, they will be checking the soil for water retention (how well the soil holds onto water) and for worm activity (how many worms are present in the soil - there might be other organisms in there but many soil organisms are too small to see with the naked eye). The farmer will be checking these things because these are two indicators of how healthy the soil is, and the more healthy the soil, the happier and healthier the plants that are grown there will be.

What happens if you check your soil and find it needs to do better on water retention or worm activity? Well, there are things you can do, and in this lesson, students will work as soil scientists to find out how to improve the health of the soil.

Find Out: Improving soil health with compost

Step 1

So, what can we do to improve the health of soil so that plants stay healthy and strong? Explain to students that there are two main things. These are:

adding nutrients to the soil in the form of fertiliser - this adds the nutrients that the plants need, and when you get healthier plants, then the soil also starts to get healthier because the plants help the soil to hold onto water as well as providing energy for soil organisms to consume
adding compost to the soil - this gives the organisms that live in the soil energy to consume which means they will make more nutrients for the plants and the plants will be stronger. Adding compost to the soil can also bring water into the soil and air - more things that are important to healthy soils.

Explain to students that regenerative growers will use organic fertilisers and compost rather than chemical-based fertilisers as they want to restore the natural systems that live in the soil. This will improve the soil in the long term and will hopefully mean that the growers won’t need to keep adding compost or fertiliser each year because the organisms in the soil and the plants will be working together to keep the soil healthy.

In this lesson, students will focus on compost.

Step 2

Students have probably heard of compost, and you might even have a compost system at your school. Students will now explore the details of compost.

Break the class into small groups. Give each group a section of the Compost Information Sheet. Each group needs to read through their section. As they read, start a mind map on the board, for example:

When they have finished reading, invite students in their groups to come up to the board and start adding the information from their section of the factsheet onto the mind map (they need to try and use keywords in the mind-map, rather than whole sentences).

Once everyone has had the opportunity to add the mind map, take a moment to talk through everyone's ideas about compost and ensure that everyone has a good idea of what compost is and how it works.

Step 3

Students will now have the chance to put on their soil scientist gloves and hats and look at compost more closely.

Note: Remind students of any safety precautions when handling compost. In addition, encourage a scientific approach of ‘do no harm’ where students work carefully with the organisms in the compost without hurting them.

Using their naked eye, students should carefully observe any creatures in the compost and record their answers to the following:

what sorts of organisms can they see with the naked eye? (e.g. worms, ants, bugs, beetles)
how many different organisms can you see in the compost?
how many different types of organisms could you see in the compost? Which was the one you found the least of?
identifying organisms can be tricky - can you give your own names to these organisms? (e.g. Wriggly Long Thing or Waddling Round)

Students will need to have a go at drawing the organisms they see.

Differentiation: You could adjust the number of drawings and the complexity of drawings based on your students. For example, students requiring extension could create more complex drawings using the Scientific Drawing Guidelines or could create a greater number of drawings. The detail required in any annotations could also be adjusted.

Step 4

Any larger organisms can be removed from the soil samples and added back to the main compost tub.

Students can then look at a sample of compost using a microscope and record their answers to the following:

how many different organisms can you see in the compost?
how many different types of organisms could you see in the compost? Which was the one you found the least of?
can you give your own names to these organisms?

Note: Where students have completed this lesson, invite them to compare what they see in the compost with what they saw in the soil.

Students will need to have a go at drawing one of the organisms they see.

Differentiation: Again, you could adjust the number of drawings and the complexity of drawings based on your students. For example, students requiring extension could create more complex drawings using the Scientific Drawing Guidelines or could create a greater number of drawings. The detail required in any annotations could also be adjusted.

You could display student drawings in the classroom (where you have completed this lesson, it could be alongside the drawing of the soil organisms students created).

Take Action: What soil do plants like best?

With their soil scientist lab coats still on, students will now need to work in groups to come up with an experiment to show farmers how adding compost to soil that is unhealthy is better for plants.

Note: Ideally, students will be able to plan and carry out their experiments. If that’s not possible, you can invite students to focus on the planning phase and justify their experiment design.

Experiment Card - what is the best type of soil for growing happy plants?

Reflection

Invite students to finish the following sentence:

Soil scientists can help farmers by …

Differentiated learning

We trust that teachers are the best equipped to know how to cater to the diversity in their classes. At Cool, we incorporate a variety of differentiation strategies into each lesson. Firstly, each lesson in this unit appeals to an array of different learning preferences. Learning activities can be completed in a number of different ways - if a student feels more comfortable speaking rather than writing, there are opportunities to accommodate this.

In lessons that feature group work or learning stations, we trust that teachers will use their discretion in knowing how to best organise their students in accordance with positive working relationships and ability. Graphic organisers and scaffolds are often included so students can ‘visually think’ and keep a record of their work. While our lessons are designed to be 55 - 60 minutes in length, we trust that teachers will manipulate lesson and segment times according to the needs of their students.

Using Compost to Keep Soils Healthy

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Summary

Learning intentions:

Students will...

Success criteria:

Students can...

Lesson Guides and Printables

Lesson Details

Skills

Curriculum Mapping

Resources Required

UN Sustainable Development Goals

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