Do Now In your own words, describe what soil is and what it’s made up of.
Aim • How do our activities help or prevent soil formation?
Soil • Weathered down rock material and organic matter • Produced by weathering and biological activity
Humus • Top layer • A dark, organic material found in soil • made from the decayed remains of plants and animals • makes soil fertile
Parent Rock • The rock from which the soil was made from • Determines the type of soil • Transported Soil • Came from somewhere else;different composition than bedrock its on • Residual Soil • Rests on top of its parent rock; same composition as bedrock its on
Soil Profile • Side view that shows layers of the soil and the bedrock beneath • Layers are called horizons
1. What role does weathering play in the formation of soil? • Soil forms as rock is weathered (clay, sand, silt) and mixes with humus.
2. What is soil made of? a. Weathered rock pieces provide minerals b. Humus c. Air – the soil is aerated when worms dig holes d. Water
3. How do plants and animals help the formation of soil? a. Organisms (like worms) mix the soil and make spaces in it for air and water. b. Microbes (decomposers) decay dead organic matter.
Soil profile: Layers are called horizons A:Top Soil: Organic and small rock materials, Humus, minerals, most fertile, organisms live here B: Subsoil: little organic matter; minerals leached from A C: Partly weathered bedrock, first stages of mechanical &chemical change D: Un-weathered bedrock
4. Why is the bedrock un-weathered? There is little water, animals, wind, and ice to cause weathering down that deep in the ground.
A darker B lighter C
Which layer contains the most biological material and why? • Why is layer D mostly unweathered bedrock?
What factors increase the rate of soil formation? • Climate (water and temperature) • Soil formation happens faster in warm, damp climates • Rock type (size and composition) • Softer rocks will break down faster …just like weathering rocks! Factors that affect soil formation
Leaching – surface water and rain carries dissolved minerals to lower layers of soil.
Why is soil important? a. All living organisms depend directly or indirectly on plants (producers) that grow in soil. b. It takes a very long time to form, soil needs to be conserved. It is not easily renewable….soil is limited.
How is soil eroded? • Removal of vegetation (grass, shrubs) that holds the soil in place. • Desertification- Drought dries out the soil turning it to dust; easily eroded by wind
How can we encourage soil formation? a. Composting – pile up grass clippings, leaves, vegetables and newspapers to create a fertile pile of soil b. Mulching lawn clippings and leaving them on the ground
Closure • What kind of soil does Long Island have? • In which horizon is the soil most fertile? • What is parent rock? • How does the parent rock affect soil composition? • Why is it important to leave leaves and grass clippings on your lawn? • What does bagging up leaves and grass do?
Brainpop - soil • http://www.brainpop.com/science/earthsystem/soil/