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SOIL & NATURAL VEGETATION. SOIL. True soil consists of four mainparts : Minerals Bacteria & Organic Material Air Moisture. FOUR MAIN PARTS OF SOIL. Minerals come from parent material Parent Material – rock, loose materials deposited by glaciers / wind / rivers
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True soil consists of four mainparts: Minerals Bacteria & Organic Material Air Moisture FOUR MAIN PARTS OF SOIL
Minerals come from parent material • Parent Material – rock, loose materials deposited by glaciers / wind / rivers • Minerals become part of soil when the rock is broken down through a process called weathering • Rock becomes smaller particles such as sand & clay • Plants need these minerals to grow • They develop nutrients such as calcium, phosphorous, potassium MINERALS
Process of weathering Large landforms break down from weather conditions such as wind, rain and temperature. Here is an example of wind driving the waves into a rocky formation in the Caribbean Sea
Process of weathering The driving force of the waves constantly hitting against rocky landforms causes rocks to fall and eventually with the constant rubbing motion against other rocks and water, the rocks begin to thin out and turn to fine grains of sand
Evolution of parent material Wind high up on a rock cliff is slowly chipping away and creating minerals from the parent material
Organic material = dead plants & animals • Organic material is decomposed by bacteria in the soil • As bacteria breaks down organic material, nutrients are released into soil • The organic material broken down by bacteria creates humus • Humus - nutrients and moisture for plants - gives soil dark colour BACTERIA & ORGANIC MATERIAL
Organic material Bacteria is breaking down organic material (leaves) which then creates humus (the nutrient, moist, dark soil)
Plants need air around roots • High humus level = air production in soil • Loose, decaying materials allows for many air pockets • Air pockets are also created by worms, insects & small animals that tunnel through soil air
Water dissolves nutrients in the soil • Dissolved nutrients are then taken in by plants through the roots • Water also helps weather rock and decay organic material through the chemical and physical process MOISTURE
A = moist soil B = dry soil Moist soil vs. Dry soil Moist soil allows for natural vegetation to take off and crops to grow more adequately. Dry soil is often dead and can not support agriculture or natural vegetation
Read page 161-162 of textbook on soil formation SOIL FORMATION
Soil forms in layers which is called a soil profile • A soil profile consists of 3 layers • Topsoil • Subsoil • Parent material • Soil forms and creates this profile as new mineral materials are added through the weathering process Soil profile
Typical soil profile A = Topsoil B = Subsoil C = Parent Material
Copy Fig. 14-2 in your notebook • Label it Soil Profile
Define the following terms: • Topsoil • Subsoil • Parent Material • Leaching • Calcification Soil formation
Read page 162 & 164 Summarize your reading on vegetation in your notebook Complete the characteristics of Canada’s vegetation regions using the information found on pages 165 - 169 Canada’s natural vegetation