Earth Science - Middle School

Soil © Copyright NewPath Learning. All Rights Reserved. 94-4550 Visit for Online Learning Resources. Photos courtesy of USGS, USFWS, & NASA. What is soil? Soil is a combination of broken down rock and decomposed organic materials. Geologists study the soil profile, which is a cross section of the soil from the surface down to the bedrock. The soil profile is divided into layers called horizons. Types of Soil Soil is classified according to climate, plant vegetation and soil composition. Different types of soil are found in different climate biomes. Plant vegetation impacts the amount of organic material called humus that is found in topsoil. A horizon Soil prole B horizon C horizon bedrock topsoil with humus subsoil weathered rock unaltered rock rock (sand, silt, clay) organic materials Tundra Taiga Temperate Rainforest Grasslands Temperate Deciduous Forest Savannah Desert Tropical Rainforest Tropical climates Arctic Desert Temperate Forest Temperate Grasslands Tropical climates with lush vegetation often have a thin layer of topsoil because high rainfall washes away humus and minerals in the A horizon. Temperate climates have the most nutrient-rich, productive soils. Moderate rainfall results in abundant plant life, and the soil profile has a thick layer of topsoil with humus. fungi worms decaying maer bacteria Life in the Soil Many organisms live in the soil and contribute to its formation. Burrowing animals help create the soil profile by breaking up rock and other materials. Worms, fungi and bacteria decompose decaying matter. Soil Conservation Soil is a non-renewable resource that can be easily depleted or destroyed. Removal of cover crops like grasses and wildflowers leads to rapid soil erosion. Without cover plants, wind can blow away topsoil and significant flooding can occur. Soil layers are thin in harsh climates such as deserts and arctic regions. burrowing animals
Pause and Review Describe the climate, plant life and soil you would expect in each of these places. Soil © Copyright NewPath Learning. All Rights Reserved. 94-4550 Visit for Online Learning Resources. desert temperate grasslands tropical rainforest Climate Soil Plant life