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SOIL. A resource our world depends on. Sand Small pieces of rock Water and air Humus (decaying plant or animal material). What is soil made from?. Food. Soil is important. Soil is important. Fertile soil is in limited supply and takes a long time to form
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SOIL A resource our world depends on
Sand • Small pieces of rock • Water and air • Humus (decaying plant or animal material) What is soil made from?
Food Soil is important
Soil is important Fertile soil is in limited supply and takes a long time to form Is considered a nonrenewable resource
Animal homes- • worms, spiders, ants, moles, foxes, rabbits live in the soil • Birds nests • Reptiles lay eggs and some build nests Soil is important
Topsoil Subsoil The Process of Soil Formation
The texture of soil depends on the proportion of sand, silt, and clay Texture of Soil
Made up of about equal parts of clay, sand, and silt • Best for growing most types of plants Loam
Sandy-drains well • Clay-heavy and sticky • Chalky- pieces of limestone • Peaty-lots of dead plant material, found in bogs, soaks up water like a sponge Different kinds of soil
Climate – hot, wet/ cold, dry/moderate • Most common plants – grassland soil/forest soil • Soil composition – rocky, sandy, rich in clay • Acidic or basic – An acidic substance changes blue litmus paper red. A basic substance changes red litmus paper blue. Classification of Soil
The value of soil is reduced when soil loses its fertility. • Topsoil can be lost due to erosion. Soil Damage and Loss
In the 1930s, a huge area of land in the US was plowed in order to grow wheat on it. • Worst drought in history began to dry the land. • Strong winds began blowing the soil away. • The area of land became known as the Dust Bowl. Almost 865 million tons of soil were blown away in 1935 alone. • Video from PBS Dust Bowl
Contour plowing- plowing along the curves of a slope • Conservation plowing- no-till plowing/leave dead crops in the ground • Crop rotation – plant different crops in a field each year Soil Conservation