Introduction to Soil! (Review, 15 minutes)
To
begin your lesson, take some time to discuss and introduce
the concept of soil science - the study of soil.
According to the USDA, there are over 50, 000 different
varieties of soil in the United States alone! The type of
soil is dependent upon the soil’ s parent material,
topography, climate, the organisms in and around the soil,
and the amount of time it takes for these to all interact.
Since these characteristics vary worldwide, soil profiles
also vary worldwide.
The above map of the United States
illustrates just a few of the diverse soil types that can
be found across the country. Soil starts with a process
called weathering. Physical and chemical weathering
processes erode parent material like rocks into mineral
particles. These materials are then transported by
volcanoes, wind, water, ice, and waves and deposit these
minerals around the landscape. The minerals are then
influenced by gravity, and upon deposition create landforms
from which soil formation begins.
There are a couple
of important minerals to consider:
- Sand: The
major mineral in sand is called quartz and it is composed
of silica and oxygen (SiO2).
- Clay: Silicates,
mica, iron, and aluminum hydrous-oxide minerals are found
in clay. The silicate clay group is primarily located in
the mid-latitudes, while the iron and aluminum clays are
found in the tropic zones.
There are many other concepts
you can expand on here including: nutrient cycling, soil
chemistry, geology, rock formations etc.
To help students
better understand soil, you can lead some simple
hands-on activities and experiments in the classroom.
Example: Building Soil
Setup an activity for student
design teams to make different soil profiles. Each team can
represent a different part of the world. Asia, North
America, Europe and South America for instance. Supply
students with the three main ingredients for soil (sand,
clay and compost) and a beaker of water.
Team Asia
- 1 cup of clay, ¼ cup of compost and ½ cup
of sand
Team South America - 1 cup of compost,
½ cup of clay and 1 cup of sand
Team North
America - 1 cup of compost, ¼ cup of sand,
¼ cup of clay
Team Europe - ½ cup of
compost, ½ cup of sand and ¼ cup of clay
Assemble all the elements at proper ratios and add a splash
of water to each.
Soils for Greenroofs
Greenroofs are
vegetated roof covers, with plants taking the place of
typical roofing material like shingles or tiles. Greenroofs
help to reduce energy costs by keeping in heat and air
conditioning, while providing a habitat for insects,
animals and birds, helping to improve air quality and
collect water from storms. The soils or “
mediums” used to grow plants on a greenroof are
usually much different than the potting soil mix or soil
you would find in your backyard.
Many organizations
are designing special kinds of greenroof soils that will
work better for the conditions of a building. One major
issue is weight. The weight of the greenroof is a concern
for any structure. Because of this greenroof soils
are lightweight and are able to retain water much
more easily than normal soils. The thin layer
in which they must be applied to roof toops reuires that
they be extremely absorbant. The Gaia Institute has
developed a soil that works great for these conditions
called GaiaSoil™ . The main ingredient in
GaiaSoil™ for is a non-toxic recycled expanded
polystyrene foam coated with an organic pectin (pectin is
the main ingredient in gelatin), and mixed with
high-quality finished compost (a fertilizer for plants).
https://www. gaiasoil. com/
This kind of soil avoids
additional reinforcement on the roof of the building,
allows a more diverse plant selection and can
capture stormwater easily, making it possible for greater
soil depth and easier transport.
Soil in Relationship to
History and the Environment (Investigate 10
minutes)
Now that students have a basic
understanding of soil, discuss the role of soil in
relationship to a current history lessons you may be
conducting. Ask students to think about how soil affected
the development of agriculture an
During the
expansion of the 13 colonies and into the Civil War Era
- soil type and quality had a lot of influence on the
formation of cities, towns and what kinds of industries
flourished in a certain area. Include lessons about local d
industry in the United States. In the south, for instance,
soils can be more clay-like - but the climate is
better for growing crops more months out of the year than
in the New England.
history - was your region of the
country heavy in agriculture or mining? How did the soil
type affect what kinds of structures were built and used
throughout history? Bring up relevant examples and discuss
as a class.
After talking about some historical influences,
discuss some of the major environmental challenges
associated with soil quality in the past and
currently:
- Agriculture and farming -
Industrial farming and monoculture crops rapidly deplete
the soil of nutrients, which are replaced each year with
chemical fertilizers. The soil is then damaged beyond
repair taking upwards of 50-75 years to restore.
-
Brownfields and superfund sites - Many areas of the
United States have been contaminated because of their
proximity to chemical waste sites or industry runoff. These
sites have been designated Brownfield or superfund sites
because of the degree of toxicity that remains in the soil
- commonly the site of oil, chemical or biological
spills.
- Erosion and mudslides - Development
for housing/buildings have caused unprecedented amount of
erosion and mudslides to occur around the world. Removing
plant life loosens the soil making it easy for wind, water
or other forces to erode the soil or cause a mudslide.
How are designers thinking through some of these
environmental challenges in the architecture or city
planning?
• Soil
Lamp - A number of designers today are integrating
objects with alternative means of clean power to create
self-contained, self-sustaining systems. For Dutch designer
Marieke Staps, the power source is mud. Her Soil Lamp makes
use of the metabolism of biological life in dirt to produce
enough energy to power a small LED light. The soil,
enclosed in cells containing zinc and copper, acts as an
electrolyte—an electrically conductive medium—and requires
only a simple splash of water to keep it from drying out.
The more cells there are, the more electricity can be
generated. Staps’ s design and naming of the Soil
Lamp celebrates the transparency and simplicity of its
process: the earth battery is housed in a clear bulbous
base, with power carried along a thin conductor leading to
a bare bulb. Exposing the possibilities of another source
of abundant, renewable energy, the lamp serves to
invigorate future innovation for small, contained power
systems.
Design Challenge: Saving Our Soils… !
(Frame/ReFrame)
After discussing some potential
challenges and historical connection, talk about some of
the recent solutions being developed by designers to
address soil conservation and quality:
-
Remediation Techniques - Many scientists and
designers are thinking of innovative ways to remediate (or
improve) soil quality. One method is Mycoremediation or the
use of mushrooms to absorb toxins in certain soil types.
Oyster mushrooms are commonly used in oil spills for
instance, accumulating the oil in a metabolic process.
Other materials like wetlands plants and other hyper
accumulators can help to remediate soils naturally.
-
Conservation/Preservation - A straightforward
technique to preserving soils and their quality is open
space preservation and conservation of sensitive lands.
-
Organic/Sustainable Farming - Sustainable
farming techniques that reduce or eliminate the use of
pesticides, fertilizers and other harmful chemicals used to
“ enrich” soils can improve soil fertility many
fold.
- Composting - Composting, or the process
of recycling organic wastes like dead leaves, food scraps
and other wastes into a fertilizer can be used to naturally
restore nutrients to soil.
Now its time for a design
challenge! In this exercise, encourage students to use
design thinking to problem-solve a scenario presented to
each team. The scenario will setup a design problem and
students will work as a team to develop a solution based on
their knowledge of soil science.
Scenario One: The mayor
has asked you to look into fixing up a former industrial
site along a major river that cuts through downtown. He
wants to turn the site into a park. The site used to be
home to the Miller-Smith Corporation. Unfortunately the
site is now designated a brownfield site because of
chemical runoff that has accumulated in the soil. What can
you do to fix the site and what kind of a park would you
design?
Scenario Two: A developer wants you to be the
lead architect on a new housing development. The
development site is partly on a steep slope with lots of
sandy soil. Design a house that would be able to
constructed on the site that would adapt to the kinds of
soil there and the steep conditions.
Scenario Three:
A big farm recently went out of business. This left over 40
acres of land that had grown just one crop - lots of
corn! The soil now looks kind of orange and dusty. When the
wind picks up a lot of the soil blows away. You’ ve
been asked to divide the land into 20 smaller farms. What
kind of a farm would you design and how would you fix the
soil?
Scenario Four: You live down by the beach.
Every year more and more condos are being built along the
shoreline. You’ ve noticed that the beach keeps
getting smaller each year, but still more houses are built.
As a town planner you’ ve been asked to help save
some of the beach from eroding into the ocean. What kind of
conservation plan would you come up with? How would you
save the beach and what would a preservation site look
like?
Sketch and Brainstorm (Generate, 10-15
minutes)
After presenting scenarios to each design
team, ask them to brainstorm and create sketches that
respond to their situation.
Model Making (Edit and
Develop, 25-30 Minutes)
After each design team
generates sketches, provide students with modeling
materials. Ask each team to develop 3D representation of
their design with the corresponding soil type as a base.
After each team completes their model, share your
design solutions as a class. Tie in historical and
environmental discussions previously held in class and
encourage students to talk about their designs from the
perspective of the soil. (Share and Evaluate)