From Bedrock to Soil What is soil formed

From Bedrock to Soil • What is soil formed from? • What is bedrock • What is humus? • What are soil horizons?

The Source of Soil • Soil is a loose mixture of small mineral fragments, organic matter, water, and air that can support the growth of vegetation. • Bedrock is the layer of rock beneath soil. • Parent rock is the rock formation that is the source of soil. • Soil that is blown or washed away from its parent soil is called transported soil. • Wind, water, and movements of glaciers can transport or move soil from one place to another.

Soil Properties • Soil is made from different-sized materials. • Soil texture is the soil quality based on the proportions of soil particles. • Soil texture can influence the ability of water movement through the soil. • Soil structure is the arrangement of soil particles. • Consistency describes a soil’s ability to be worked and broken up for farming. • Infiltration is the ability of water to move through soil.

Soil Properties • Some soils are rich in nutrients, some are poor in nutrients. • Soil fertility is the soil’s ability to hold nutrients and to supply nutrients to a plant. • Humus is the dark, organic material formed in soil from the decayed remains of plants and animals.

Soil Horizons • Soil horizons are the horizontal layers of soil. • The top layer of soil is called topsoil, containing more humus than the other layers of soil, rich in nutrients plants need to be healthy. • Good topsoil is necessary for farming.

Soil p. H • Soils can be acidic or basic. • The p. H scale, ranging from 0 to 14, is used to measure the acidity of a substance. • 7 is neutral; below 7 is acidic; above 7 is basic. • Different plants need different types of soil. • The right p. H for a soil depends on the plants growing in it.

Summary • Soil (loam) is formed from the weathering of bedrock. • Soil texture affects how soil can be worked for farming and how well water passes through it. • The ability of soil to provide nutrients so that plants can survive and grow is called soil fertility. • The p. H of a soil influences which nutrients plants can take up from the soil. • Different climates have different types of soil, depending on the temperature and rainfall.

Quick Check 1. Soil that is blown or washed away from its parent rock 2. The layer of rock beneath the soil 3. A rock formation that is the source of mineral fragments in the soil 4. A loose mixture of mineral fragments, organic material, water, and air that can support vegetation a. soil b. transported soil c. parent rock d. bedrock

Quick Check 1. Soil quality based on the proportions of soil particles 2. The arrangement of soil particles 3. Ability of water to move through soil 4. Soil’s ability to be broken up for farming a. soil structure b. infiltration c. consistency d. soil texture

Quick Check What is soil’s ability to hold nutrients and to supply nutrients to a plant? a. b. c. d. Soil structure Soil texture Soil horizons Soil fertility

Quick Check What do we call the removal of substances from soil due to water passing through it? a. b. c. d. Wedging Infiltration Erosion leaching

Quick Check What is the layer of soil that often contains the most humus? a. b. c. d. Horizon Parent rock Topsoil bedrock

Quick Check What is soil that has a p. H below 7 called? a. b. c. d. Neutral Acidic Basic midpoint

Quick Check What is the correct p. H for growing plants? a. b. c. d. 7 Above 7 Below 7 It depends upon the plant

Soil Conservation • Why is soil important? • How can human activity affect soil erosion? • What are three important benefits that soil provides? • List five methods of soil conservation.

Soil Conservation • Soil can be endangered, just like plants and animals. • Soil is important because it provides nutrients to plants, provides houses for animals, and stores water. • It takes thousands of years for soil to form, it is not easy to replace. • Soil conservation is a method to maintain the fertility of the soil by protecting the soil from erosion and nutrient loss.

The Importance of Soil • Soil provides minerals and other nutrients for plant life. • All animals get their energy from plants. • Soil also provides a place for animals to live. • The region a plant or animal lives is called a habitat. • Soil holds water for plants to get the moisture or nutrients they need.

Soil Loss and Damage • Soil loss is a serious problem around the world. • Soil damage leads to soil loss. • Soil becomes damaged from overuse, by poor farming techniques. • Soil damage also can come from overgrazing. • Overused soil can lose its nutrients and become infertile

Soil Loss and Damage • Plants will not grow in soil that is infertile. • Without plants to hold and help the cycle water, the area can become a desert. • Without plants and moisture, soil can be blown or washed away. • Soil left unprotected can be exposed to erosion. • Roots from plants and trees act like an anchor to hold soil in place.

Soil Erosion • Human activity can accelerate soil erosion when those activities affect plant roots. • Plants and trees protect the soil. • By taking care of the vegetation, you also take care of the soil.

Summary • Soil is important for plants to grow, for animals to live in, and for water to be stored. • Soil erosion and soil damage can be prevented by no-till farming, contour plowing, terracing, using cover crop, and practicing crop rotation.