What’s In Your Soil?

1. What’s In Your Soil?

2. Table of Contents SOIL BASICS • Overview: Soil Basics Slides 3–4 • Video: Soils Are Living! (3.00 mins) Slide 5 • Fun Facts About Soil Slides 6–7 SOIL COMPOSITION • Soil Types & Textures Slides 8–11 • Soil Texture Tests & Measurements Slides 12–14 SOIL BIOLOGY • Soil Biology: Ecosystems Under Our Feet Slides 13–22 • Video: The Soil Beneath Our Feet (2.50 mins) Slide 23 • Soil Biology: Under the Microscope Slides 24–27 • Soil Health and Best Practices Slides 28–29

3. Let’s start with the big picture

4. Soil is vital to life on Earth • Soils provide the medium for growing all kinds of plants. • Soils provide habitat for animals and organisms that live in the soil – which accounts for most of the living things on Earth! • Soils emit and absorb gases (such as carbon dioxide, methane, water vapor) and dust. • Soils absorb, hold, release, alter and purify most of the water in terrestrial systems. • Soils process recycled nutrients, including carbon, so that living things can use them over and over again. This is often done in partnership with living organisms. • Soils act as a living filter to clean water before it moves into an aquifer. • Soils serve as support against erosion.

5. Soils are living! (and always changing) “Soils Are Living!” | video from Soil Science Society of America https://www.youtube.com/watch?v=Qas9tPQKd8w • Soil is a living, dynamic natural resource. It helps us sustain life — our food, clothing and shelter come from soil. But soil doesn't do its job alone. Animals large and small — including microscopic — live in soil. This biodiversity is critical to a healthy world.

6. Did you know?

7. Fun Facts About Soil Without soil, there would be no jeans. • That's right! Jeans are made of cotton denim stitched together with cotton thread. Their blue color comesfrom indigo dye. Cotton and indigo come from plants that need soil to grow. Without soil, we couldn't even eat breakfast! • Everything from the wheat in cereal to the oranges in orange juice to the animal proteins in milk, bacon, and eggs were nourished by the soil and what grows in it. Even a ceramic plate is made of a type of soil. No soil, no breakfast and no plates from which to eat. Source: Field Museum, Chicago IL

8. What is soil made of? • Minerals (from clay, silt, sand, gravel, stones) • Water (from rain and melting snow) • Organic matter (from decaying plants and animals, and living organisms) • Air (from pores and chambers created by insects, worms and burrowing animals)

9. Soil composition: Let’s break it down Soil particles, categorized by size • The particles that make up soil are categorized into three groups by size: Sand, silt and clay. • Sand particles are the largest and clay particles the smallest. • Most soils are a combination of these three.

10. 3 Soil Particles > 6 Main Soil Types

11. Soil Particles & Texture Types • Sand: The largest-sized soil particles. Also refers to a soil texture that consists of at least 85% sand particles. • Silt: Soil particles in between sand and clay in size. Also refers to a soil texture that consists of at least 80% silt particles. • Clay: The smallest-sized soil particles. Often have plate-like shapes. Also refers to a soil texture that consists of at least 40% clay particles. What is soil texture? Soil texture = The proportions of sand, silt and clay particles.

12. Soil Texture Triangle: 12 Soil Subtypes

13. Soil Testing: “Texture By Feel” Determining a soil's texture by feel (and rolling it around in your hand) is an important skill for students of soil science. Soil texture strongly influences the nutrient-holding ability of a soil, the amount of water the soil can store, and many other properties. This is a serious scientific exercise! • Sand feels gritty. • Silt feels like flour (smooth and velvety). • Clay feels sticky when wet.

14. Soil Basics: Texture and the Soil Triangle <embed video> https://www.youtube.com/watch?v=8nU26sXVNS4 Video: Soil Texture and the Soil Texture Triangle (4.07 mins) Source: Purdue Extension

15. Soil Biology: Ecosystems Beneath Our Feet

16. Ecosystems Beneath Our Feet Soil is so much more than just dirt; it houses an entire ecosystem! Healthy soil is full of life — from microbes to bugs to burrowing rodents. Just one gram of fertile soil can contain up to one billion bacteria!

17. Ecosystems Beneath Our Feet Different organisms all serve a purpose in the ecosystem, converting different organic matter into specific nutrients that can be used by the plant. In return, the plant gives back nutrients to the organisms and provides shelter for them. It also prevents the erosion of the soil with its root structures.

18. Ecosystems Beneath Our Feet Organisms like earthworms, bacteria and fungi: • Decompose into rich humus • Release nutrients • Create pores to aerate the soil • Stabilize the soil (to protect from erosion)

19. Recycling Nutrients | Beneath Our Feet One of the main functions of this ecosystem is to recycle nutrients such as nitrogen, potassium and phosphorous — which are vital to a plant’s growth. When a plant or animal dies, those nutrients are still part of their matter. Organisms help decompose the dead matter and recycle those nutrients back into the soil.

20. Recycling Nutrients | Beneath Our Feet While these nutrients are vital to a plant’s growth, they are sometimes in short supply, depending on the health of the soil. Therefore, they’re often added to agricultural and garden soils. • Nitrogen (N) – Macronutrient essential to living things like plant growth. • Potassium (K) – Macronutrient essential to all living things like water increase and pest resistance in plants. • Phosphorus (P) – Macronutrient essential to all living things like flowers, fruits, seeds in plants.

21. What is the nitrogen cycle? It’s the way that nitrogen is changed into many different forms in nature — in order to be usable by plants and animals. Air is about 78% nitrogen. Nitrogen is needed for life on Earth! It is an important part of proteins, DNA and RNA. In plants, nitrogen is needed for photosynthesis and growth. The problem is that plants and animals don't have the right enzymes to capture (or “fix”) atmospheric nitrogen. They depend on bacteria to convert the nitrogen into a form they can use. (In nitrogen fixation, bacteria convert it into ammonia, a form of nitrogen that plants can use. Then, when animals eat the plants, they get usable nitrogen as well.)

22. What about fertilizers? Once crops are harvested, the natural supply of nutrients in the soil must be “re-filled”. This is why farmers add nutrients to their soils. Nutrients can be added from a variety of sources—organic matter, chemical fertilizers, and even by some plants. Farmers use fertilizers because they contain plant nutrients such as nitrogen, phosphorus and potassium. Fertilizers are simply plant nutrients applied to agricultural fields to supplement required elements found naturally in the soil. Fertilizers have been used since the start of agriculture. Native American people used crude fertilizers, such as burying a fish in their corn plots, and organic farmers use fertilizer from natural source, such as compost. Most farmers today use fertilizers that are either mined or manufactured.

23. What about fertilizers? (continued) Fertilizer use is very expensive and can harm the environment if not used correctly. By testing their soil, farmers know which nutrients—and how much—to apply to the soil. If too little is added, crops will not produce as much as they should. If too much is added, or at the wrong time, excess nutrients will run off the fields and pollute streams and groundwater. To stay healthy, humans need to acquire essential nutrients from many different food sources. The demand for food and other products from agricultural systems will increase over the next few decades. This means that we need to keep our soils healthy and full of nutrients in order to feed the growing population. Learn more at Soils Matter, Get the Scoop! | The Soil Science Society of America

24. Did You Know? A teaspoon of good farm soil contains up to 1 billion bacteria in more than 4,000 species. Source: Smithsonian Environmental Research Center

25. Under the Microscope The Living Soil Beneath Our Feet | California Academy of Sciences https://www.youtube.com/watch?v=MlREaT9hFCw • Travel underground for an up-close look at the ants, amoebas and bacteria that maintain healthy soil. Glimpse this microscopic world and learn about the symbiotic relationship between fungi and tree roots.

26. Under the Microscope • Bacteria are one-celled organisms that do important work in the decomposition process.

27. Under the Microscope • The organisms living in the soil range from those we can easily see, like earthworms and spiders, all the way down to single-celled bacterium and protozoa.

28. Under the Microscope • Fungi are spore-producing organisms that do not contain chlorophyll. Molds, mushrooms and yeasts are all fungi.

29. Under the Microscope • Protozoa are one-celled organisms that live in water or as parasites in plants or animals, including amoebas.

30. Soil Health: Basic Management Principles Managing for soil health is one of the best ways farmers can increase crop productivity and protect against drought while improving the environment. Following are four basic principles to improving the health of your soil: 1. Minimize disturbance (reduce tilling) 2. Maximize soil cover (planting cover crops) 3. Maximize biodiversity 4. Maximize presence of living roots – Natural Resources Conservation Service, USDA

31. Soil Health: Healthy Practices • As world population and food production demands rise, keeping our soil healthy and productive is of paramount importance. By farming using soil health principles and systems that include no-till, cover cropping and diverse crop rotations, more and more farmers are actually increasing their soil’s organic matter and improving microbial activity. • As a result, farmers are sequestering more carbon, increasing water infiltration, improving wildlife and pollinator habitat—all while harvesting better profits and often better yields. – Natural Resources Conservation Service, USDA