Scooby Doo & the Gang need you to get your hands dirty by helping with digging for clues in the soil.
To solve this case, you must find out what soil is, why it is important, and in what kinds of soil plants grow. Happy digging!
When you finish this case, you should be able to:
Understand the importance of soil and how the things that are in it relates to its ability to support good plant growth.
Tell how plants adapt to soils that aren't perfect.
Describe the relationship between soil and plant life.
Recognize that there is a lot of important activity going on where the roots of plants are located.
Use new vocabulary words such as nutrients, soil particles, texture, structure, organic matter, topsoil, and subsoil.
Describe what types of living organisms can be found in and around soil.
Use observation and classification to identify components of the soil.
Recognize other things that can be used in place of soil.
Describe the importance of soil "critters" and how they break down organic matter.
While you're solving the mysteries, pay special attention to these key ideas:
Soil makeup is important in keeping plants alive. We can change soil composition in ways that will help a plant's ability to survive and grow.
Microbes, solid particles, chemicals, and living plant material all work together to produce a balance that supports a variety of life forms.
Soil is made up of three basic units: sand, silt, and clay.
Composting is nature's way of changing organic wastes into plant food that is used to keep many living things alive.
Before you can solve the mysteries, you'll need to learn the facts of the case.
Four Major Components of Soil
Once you step out onto a piece of ground, you step out onto something that is alive. Soil is not just a piece of dirt. Soil is made up of living and nonliving material spread as a very thin layer over the entire surface of the planet we call earth.
Soil must provide nutrients, water, and air and helps to support the plant.
Soil is a combination of materials. One part of soil is rock that has been broken down over time by wind, water, and chemical processes. Another material is called organic matter. It is made up of decaying plant and animal matter. Water and air are the other ingredients in soil. In a good garden soil, about 45 percent will be rock particles, 5 percent organic matter like leaves, 25 percent water, and 25 percent air.
Soil Types
People describe soil types in all kinds of ways such as heavy, light, sandy, clay, loam, poor or good. Soil scientists describe soil types by how much sand, silt and clay are present. This is called texture. It is possible to change the texture by adding different things. Changing texture can help in providing the right conditions needed for plant growth.
Sand is the largest particle in the soil. When you rub it, it feels rough. This is because it has sharp edges. Sand doesn't hold many nutrients.
Silt is a soil particle whose size is between sand and clay. Silt feels smooth and powdery. When wet it feels smooth but not sticky.
Clay is the smallest of particles.
- Clay is smooth when dry and sticky when wet. Soils high in clay content are called heavy soils. Clay also can hold a lot of nutrients, but doesn't let air and water through it well.
- Particle size has a lot to do with a soil's drainage and nutrient holding capacity.
- To better understand how big these three soil particles are, think of them like this. If a particle of sand were the size of a basketball, then silt would be the size of a baseball, and clay would be the size of a golf ball. Line them all up, and you can see how these particles compare in size.
Take a Closer Look: What Is Soil?
You might think that soil is just dirt . . . but it is much more than that! SCOOBY & the GANG discover all the things that make up the different kinds of soil.
What color is it?
What does it feel like? What does it smell like?
Try separating the soil into different parts. Put things that are alike in piles such as all sticks with sticks, and all roots with roots. Record what you find.
What else can you tell about the soil?
Nutrients from the Soil
Most living things need three basic things to survive:
If you said that plants get their nutrients and water from the soil, you are right! Although all green plants make their food by photosynthesis, they also need to get nutrients from the soil. These dissolve in water and are taken up by the roots of the plant.
The most important plant nutrients are nitrogen (N), phosphorous (P), and potassium (K).
Nitrogen helps above-ground leafy growth and gives dark green color to leaves.
Phosphorous encourages plant cell division. Without phosphorous, flowers and seeds could not form. Phosphorous also helps root growth and protects the plant from disease.
Like phosphorous, potassium increases the plant's resistance to disease and encourages root growth. Potassium is needed for the making of chlorophyll.
Why Is Soil So Important?
Soil is important for plants because it holds roots that provide support for plants and stores nutrients. Detective Le Plant is searching for secrets in the soil. Help him uncover the ingredients of soil that are important to plant growth.
Soil for Gardening in Containers
When growing plants in containers, soil from the garden should not be used if you expect good results. Garden soil usually contains weed seeds, disease organisms, and drains poorly. If you want to use soil from the garden, it must be mixed with other things. Here's a good recipe:
The peat and sand will help to improve the drainage.
Even better for growing plants in containers are artificial soils or soilless mixes. They are called artificial because they contain no soil but are made up of peat, perlite, vermiculite, and nutrients. They have a lot of plusses over soil. They are clean, lightweight, provide for excellent drainage, and easy to get. Soilless mixtures are available under several trade names such as Jiffy mix, Redi-earth, Pro mix, and Sunshine mix. Because artificial mixes contain no soil, they don't do a good job of holding on to nutrients. So, you will need to fertilize plants regularly to keep them looking good.
Composting
Composting is the natural cycle of plants living, dying, and breaking down to pass their nutrients to other plants. Compost is a source of nutrients for plants. It helps to improve the texture and fertility of the soil. You learned about texture earlier in this case.
Compost is made up of a lot of different things. Think of compost as the soil's diet. The diet should be balanced between materials that are high in nitrogen and those high in carbon, between wet and dry materials, and between acidic and basic materials.
Microorganisms in the soil break down the organic matter to make compost.
The basic compost pile is made up of layers of organic matter, sprinkled with a little soil and fertilizer, kept moist and turned to keep oxygen going through it. You can speed up the process by making the size of the organic matter smaller and by turning the pile frequently.
There are four basic ingredients in a compost pile:
Carbon (from organic matter like leaves) provides the food for microorganisms.
Nitrogen (the fertilizer) comes from grass clippings and dead green plants and provides the energy microorganisms need to break down the carbon.
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VOCABULARY TERMS & DEFINITIONS
Organic Matter
Naturally occurring plant and animal resources. Organic matter is a part of compost.
Texture
The coarseness or fineness of the soil.
Sand
The largest of the soil particles. It is huge when it is compared to clay.
Silt
Silt is a soil particle whose size is between sand and clay. Silt feels smooth and powdery. When wet it feels smooth but not sticky.
Clay
Very, very, very fine soil particles.
Nitrogen
This is one of the "big three" plant nutrients. This one is used in large amounts by plants. Nitrogen helps plants make lots of leaves and is important in helping plants get their green color. N is the chemical symbol for Nitrogen.
Phosphorous
One of the "big three" plant nutrients. It helps plants to make more or larger flowers and to build a strong root system. It's checmical symbol is P.
Potassium
One of the "big three" plant nutrients. Potassium helps plants to fight off diseases. It's chemical symbol is K.
Peat
Partially decayed plant matter formed on the surface of water-logged soils.
Perlite
White, hard, rock-like material used to make potting soil. Looks like small bits of popcorn.
Vermiculite
Another part of soil mixes. This material is lightweight, tan in color, and can hold water.
Compost
A mixture of plant parts (leaves, stems, flowers) and soil that has been piled up, soaked with water, and allowed to rot. Gardeners use compost to help make soil a better place for plants to grow.
Acidic
Soil with a pH below 7.0.
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Basic
Soil with a pH above 7.0.
Organic Matter
Naturally occurring plant and animal resources. Organic matter is a part of compost.
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All About Seeds
Seed Structure
Some seeds require proper light also. Some germinate better in full light while others require darkness to germinate.
Nonflowering plants like ferns reproduce by "seed-like" structures called spores. Spores are usually found on the undersides of leaves and look like tiny tufts of velvet. Spores are ripe when they easily fall off the leaf. You may want to try to germinate them but it takes a long time for germination and for a plant to develop.
Spore