NOVEMBER 4, 2015 Silently title your notes: LAYERS OF SOIL

What is Soil? Soil is loose, weathered material on Earth’s surface where plants can grow! It is a natural resource, meaning that humans do not make it. It is a mixture of rock particles, minerals, decayed organic material, water, and air.

Importance of Soil Everything that lives on land, including humans, depends on soil! Bricks, pottery, and other items are made from clay & soil Animals live in soil; without it, they would have no place to live! Plants need soil to grow

So Much Soil! There are more than 70,000 types of soil in the USA! Soils differ from each other by:  How much water they hold  Color  Size of rocks found in them  Minerals and rocks that make up the soil

What makes up soil? Bedrock- the soil layer of rock beneath the soil Gravel, sand, silt, and clay- make up a large portion of soil that comes from weathered rock Humus- the decayed, organic material in soil that contains nutrients for plants  For example, when a leaf falls from a tree and breaks into smaller pieces, that is humus!

Soil Layers The layers of soil create a soil horizon. Soil layers are determined by differences in color, texture, and what it is made of. There are 5 layers in soil!

Top 3 layers 1. Humus- very top of the soil; made up of live and dead plants, bugs, & worms. 2. A horizon- made up of topsoil, which is a mixture of humus, clay, minerals, and dead plants 1. Earthworms, ants, and other small insects and animals live in topsoil! 3. B horizon- made up of subsoil, which consists of clay, rock particles, and a tiny bit of humus. Forms from rain carrying the A horizon into the ground

Bottom 2 layers 4. C horizon- made up of weathered bedrock. This is also known as parent material. Nothing lives down here except for very large tree roots. 5. Bedrock- A solid layer of rock. These rocks can weather and move to the other horizons.

NOVEMBER 10, 2015 Silently title your notes: SOIL Day 2!

How do living things affect soil? Decomposers- the organisms that break the remains of dead organisms into smaller pieces and digest them with chemicals. This material then mixes with soil to create humus  Examples: mushrooms, bacteria, and worms Mixing the soil- when animals and insects move about the soil, they carry pieces from horizon A down to horizon B, and pieces from horizon B up to horizon A  Examples: mice, moles, prairie dogs, and worms.

Damaged Soil Soil can be easily damaged when its fertility or topsoil is lost due to erosion. 1. Loss of fertility can occur when sand becomes dry and loses nutrients due to too many crops being grown on it. 2. Loss of topsoil can occur when water and wind erode it. When there are few plants and roots in the topsoil, wind can easily erode the soil. This creates a Dust Bowl.

1934 Dust Bowl While watching the video, think about the following questions: 1. What did humans do that caused loose soil? 2. What else led to the loss of topsoil? 3. How high did the dust go?

How can we help conserve soil? There are three main ways we can conserve soil: 1. Contour Plowing: farmers plow their fields along the curve of a slope instead of in straight rows. How does this help soil? This will help slow the runoff of excess rainfall and stop the rain from washing the soil away.

How can we help conserve soil? 2. Conservation Plowing: dead weeds and stalks from the previous year’s crops are plowed into the ground to help return soil nutrients, retain moisture, and hold soil in place. 2. Crop Rotation: when farmers alternate planting crops that require many soil nutrients with crops that require fewer soil nutrients.

We can help Soil! While you watch the video, think about the following questions: 1. What leads to soil degradation (the limited supply of good, fertile soil)? 2. What has the ELD done to help the soil? 3. What percent of land is already degraded (not as good)