The soil is the source of life, creativity, culture, and real independence. David Ben Gurion (1886-1973), HazonVeDerek, 1951 SOIL
Just What Is Soil? • It is where life and life processes begin on land. • It is the material that constitutes the outermost solid layer of our planet. • It is a naturally-occurring mixture of minerals, air, water and organic ingredients. • It is formed by the dynamics of chemical and physical weathering.
Soil Composition • Soil is composed of four major components: • Minerals or rock particles – 45% • Water – 25% • Air – 25% • Organic matter such as leaves – 5%
The Soil’s Ecosystem • Soil is a home for many living things such as worms and many microorganisms that you cannot always see with your eye. • The soil’s ecosystem is a source of food for the organisms that live there. • The soil’s ecosystem is a protective area.
Soil Properties • How do soils differ? • Composition • Texture • Color • Porosity – the ability to retain water • Permeability – the ability of water to move through the soil • Nutrients – the ability to support plant growth
Soil Composition • Observing the sample with a hand lens • Touching the dry sample • Rolling the moist sample • Smearing • Settling
Soil Texture • The way soil “feels” is called the soil texture. • Soil’s texture depends on the amount of each component and the size of its particles: • Sandare the largest particles and they feel gritty • Siltare medium-sized and they feel soft or silky like flour • Clay are the smallest-sized particles and they feel sticky and hard to squeeze.
Soil Texture • In the Classroom • Coffee Grounds, Flour and Modeling Clay • In the Environment • Sand, Silt and Clay • Dichotomous Key • Guide to Soil Texture by Feel
Barrel Sand(feels gritty) (2.00 - 0.05 mm, USDA) (2.00 - 0.02 mm, ISSS) Plate Silt(feels floury) (0.05 - 0.002 mm, USDA) (0.02 - 0.002 mm, ISSS) Coin Clay(feels sticky) (< 0.002 mm, USDA) (< 0.002 mm, ISSS) Relative Size Comparison of Soil Particles
Value • Degree of lightness or darkness of a color • Black: 0/ • White: 10/ • Gray: halfway between black and white 5/
WaterRelationship • Porosity – the ability of soil to hold water • Permeability – the ability of water to move through the soil • Dependent on soil particle size • The larger the particle size the more movement • Saturation Rate – the point where no more water can be absorbed or moved through the soil
Soil Provides Nutrients • Washed down from the O and A horizons. • Held in the B Horizon by presence of clay • Absorbed by the plant’s roots to provide food to the plants.
Soil Profile • A soil profile is a slice of earth several feet deep. • By studying soil profiles, scientist learn about the soils characteristics and how to use and protect it. • Soil profiles are made up of several layers called horizons - each with their own job.
The Soil’s Horizons • The surface layer or the O Layer is made up of organic material like leaves and grass. • The A horizon is a mixture of decayed organic material and minerals. • The B horizon is the most active layer. It is where the nutrients and moisture is stored. • The B horizon is also called the root horizon. This is where plants’ roots reach out and pull nutrients and water into the plants. • The C horizon is the area of parent material that helps to make the soil.
Soil is Formed by Weathering • Biological: • Roots of plants • Lichen • Burrowing and digging by animals and insects • Physical/Mechanical: • Freezing water • Wind • Running water • Frost • Chemical: • Acid rain • Minerals are dissolved
Soil Conservation • Apple Demonstration • Soil Stories • Soil Is Not Trivial • Enviroscape • Cookie Mining • From Apple Cores to Healthy Soil • Composting (Presented by Solid Waste Management Authority)
Respectthe 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.
OMS science teachers thank the following for their assistance with this unit. • Summit County Educational Service Center Standards-Based Science Curriculum Includes: • Model Curriculum-Content Statement(s) • Model Curriculum-Content Elaboration Concepts • Model Curriculum-Visions Into Practice (V) • A Framework for K-12 Science Education: Practices , Crosscutting Concepts, and Core Ideas (F) → Next Generation (Next Gen) Science Education Standards • Strategies for Teaching and Learning • MissiZender-Sakach • Science Consultant • Summit County Educational Service Center • Sandy Barbic • Education Specialist • Summit Soil & Water Conservation District • Debbie Rohr • Consultant • Summit County Educational Service Center