All About Soil

What Is Soil?

Soil is the top layer of the earth where plants are sown and grown. It's made up of unconsolidated organic material and minerals. The matter that makes up soil is affected by the micro and macro organisms that live in and feed off of the soil and the water and temperature elements of the surrounding climate.

• Soil: An Explanation: Soil can include minerals, bacteria, fungi, and pieces of rock.
• >How Climate Impacts the Soil: Climate change has an impact on the soil because soil is the second-largest repository of carbon.
• Soil Types and Gardening: The type of soil you choose affects the plants you'll be able to grow.

What Is Dirt?

Dirt is soil that is no longer able to support life. In a way, it's deactivated soil. When soil gets stuck on our clothes, it becomes dirt. Unlike dirt, soil has seven important roles:

1. Soils absorb and emit greenhouse gases such as methane and carbon dioxide.
2. They purify the water in land-based ecosystems and process nutrients so that they can be reused by other organisms.
3. Fossils and archeological elements can be preserved in soil. Soil can also accelerate the decomposition of man-made structures through the weathering process.
4. Buildings and their foundations are built on soil.
5. Living organisms have habitats in the soil.
6. Many different types of plants can grow in the soil.
7. Before water drains into an aquifer, it's purified by the soil.

• How Dirt Cleans Water: It's safe to drink groundwater because it's been purified by the soil.
• How Trees Improve Soil: Trees protect the soil more than other plants because they help to halt soil erosion.
• Fossil Preservation: Animal tracks and teeth that are preserved by layers of soil teach us about the evolution of plant and animal life.

Soil Profile

Soil has six horizons. A horizon is a layer of soil.

1. The O horizon is an organic layer made up of decomposing biological matter like leaves. The O horizon may be of varying levels of thickness. Some soils don't have an O horizon.
2. The A horizon is the topsoil and is a mix of mineral and organic matter. The A horizon is the layer of soil that is best for plant growth.
3. The E horizon consists of eluviated soil, which means that most of the minerals, clay, and organic matter have been drained from the soil, leaving behind primarily sand and silt.
4. The B horizon is the subsoil and is the depository of the clay and minerals that were leached from the E horizon.
5. The C horizon is parent material, the birthplace of soil as we know it. It's mostly broken-up bedrock and contains little to no organic material.
6. The R horizon is pure bedrock. Although it's considered to be a soil layer, it's not really soil; it's the ultimate parent material.

• Types of Parent Material: Parent material determines the properties of the subsequent soil layers.
• How Soil Horizons Form: The number and size of soil horizons in a location will be affected by climate and age.

Additional Soil Resources

• Granite, an Igneous Rock: You may have seen granite used for countertops because of its hardness and the attractive streaks through the light-colored rock.
• Basalt: Basalt is the most common igneous rock and is usually found in or around volcanoes.
• Quartzite vs. Quartz: Quartzite naturally occurs in the soil, while quartz is engineered in factories as a derivative of quartzite.
• What Is Limestone? Limestone is formed of mineral composites like calcite and fossils and is found in the sedimentary soil layer.
• Sandstone: Sandstone is formed when the pressure of soil layers forces individual sand grains together.
• Soils Minerals and Plant Nutrition: Soil has both primary and secondary mineral sets.
• Clay in the Soil: Clay is a naturally occurring element in the soil that is formed when rocks with feldspar erode over decades or centuries.
• Determining Soil's Age: Older soils have thicker soil horizons.
• Soil's Secrets: How to Water Flowers and Grass: An inch of rain could sink up to a foot deep into the soil.
• What Is Permafrost? When soil layers are frozen for a minimum two-year period, this is called permafrost.
• Soil Animals: Soil animals are animals that feed from the soil, deposit nutrients, and decompose in the soil.
• How Soil Can Affect Construction Projects: Long-term construction projects can only be built on stable soil.
• Want Clean Water? Filter it With Soil: Soil plays an important role in changing the structure of contaminants and pollutants.
• Recycling Organic Matter to Improve Soil Quality: Recycling organic materials into the soil improves the quality of the soil and promotes the health of the surrounding ecosystem.
• Role of Bacteria Living in Soil: Mutualists, pathogens, lithotrophs, and decomposers are the main groups of soil bacteria.
• Desert Soils: Soil in the desert is actually quite fertile, but the lack of moisture restricts the types of plants that can grow.
• Gases Released by Soil: Soil plays a role in the absorption and emission of greenhouse gases.
• Wetter Soil Is Leading to Reduced Methane Absorption: Wet soil is less likely to absorb methane gas from the air.
• Ways You Can Protect the Soil: These five tips will help you to preserve your soil.
• Soil Enrichment Techniques: Adding mixed compost and other organic matter enriches the soil.

Written By Ava Rose.