Download 1-20-15 About 2 inches of soil across the earth Soil

1-20-15
About 2 inches of soil across the earth
Soil - a complex plant supporting system made up of disintegrated rock, remains and wastes of
organisms, water, gases, nutrients, and micro organisms.
About 38% of earth's surface (land) is used for agriculture.
Forestry
Soil cycles nutrients
Flow of energy
Medications can come from soils.
Soil formation is affected by:
1. Climate - long term. Soils form faster in warm, moist climates 2. Organisms - worms (intestines of the
earth). Ingest soil, take out nutrients, then expel what they can't use. They help form holes in the soil.
Oxygen. Ants. Moles. Voles. Mice. Excavate the ground. Mix the soils. Adding organic material to soil
through defecation.
3. Land forms - hills and valleys. Steeper the slopes the more erosion and runoff. The best soils located
in the middle of the mountain.
4. Parent material - gives the soil it's chemical and physical characteristics 5. Time - takes time to form
soil. 100 years to form 1 inch of soil in a deciduous rain forest. In desert takes 1,000 years to form 1 inch
of soil.
Soil forms through weathering, deposition, decomposition
Composition of soils. 45% is minerals. 25% air, 25% water, 5% organic