Plants and Soils Study Guide
Plants are producers. All plants are made up of cells. The cells are the small units
all living things are made up of. The cells hold the chlorophyll that the plant needs
to produce food. Chlorophyll gives plants their green color. It helps the plant use
the suns energy to make food.
They have several main parts – roots, stems and leaves. The roots are the
underground part of the plant. It holds the plant and place and takes in the water
and nutrients from the soil.
The stem connects the roots of the plant to the leaves. It supports the plant
above ground. It carries water from the roots to the leaves.
The leaves of a plant take in light and air. This is where the plant produces food.
Plants grow from seeds. Seeds contain several parts – the young plant, the stored
food and the seed coat. The seed coat protects the seed like a layer of skin. The
stored food feeds the young plant while it begins to grow until it can produce its
own food. Plants spread seeds to grow new plants. Seeds get spread by air, water
and by animals.
When a seed germinates, it breaks out of the seed and starts to grow. A seedling
is a young plant. It is up out of the ground and has started to produce its own
food.
A simple plant has no roots, stem or leaves. It has to grow close to the ground so
it can get all of its needs directly from the environment. They tend to grow in
damp and shady places.
Photosynthesis is the food making process in the plants. During photosynthesis
takes sunlight, chlorophyll, nutrients from the soil, air and water to produce food
for the plant.
Soil is loose material made of minerals, humus, water and air. It creates a layer in
which plants can grow in the upper layer of Earth. Different types of soil have a
different combination of those 4 parts. It takes between 500 and 1000 years for
an inch of new soil to form.
Humus is a part of soil. It is made up of decayed parts of once living things.
Humus provides many of the nutrients plants need to grow.
Loam is the best type of soil for growing most plants. It has a mix of large and
small grains and contains a lot of humus. It is a dark and rich soil.
Clay is a type of soil with very small grains. Because of this, it holds a lot of water
and is sticky.
Sand is a type of soil with very large grains. It has a lot of air and water flows
through it very easily.
Soil has three layers – top soil, subsoil and bedrock. Topsoil is made up of the
smallest grains and has the most humus. It is the best layer for growing plants.
Subsoil is the middle layer. Subsoil has larger grains and more rock and less
humus. Bedrock is a solid layer of rock under the subsoil.
Because it takes so long for new layers of soil to form, it is important to conserve
it. You can conserve soil by using it carefully. You need to keep it from being
eroded away. The roots of plants help keep this from happening.
One way to conserve soil is strip cropping. When farmers plant their fields, they
should plant strips of grass or clover between the rows of crops to keep soil from
being washed away.
Another way is by contour plowing. When farmers plant fields on the side of a hill,
you plant in rows around the hill rather than up and down to keep the soil from
washing away.