Introduction to Soils Soil is made up of

Introduction to Soils

Soil is made up of:

Functions of the Soil l l Supply Nutrients Supply Water Supply Air Provide Anchorage

Nutrients l l l 17 essential nutrients Soil provides 14 of these nutrients 13 originate in parent rock where soil developed Nitrogen is the exception Nitrogen comes from Organic Matter

Water and Air l l l Water enters through roots Water helps transport nutrients Water helps with chemical reactions Water helps keep the plant cool Air and water are located in pore spaces Air supplies oxygen for respiration or plant roots

Anchorage for Plants l l Holds plant upright Allows it to receive sunlight it needs Roots comprise 30 to 50 percent total mass Roots absorb oxygen, water, and nutrients

People Depend on Soils l l l Soils are where plants grow Standards of living dependent on the quality of soil Animals are grown based on soil Soils are foundation of our houses Soils serve as the bed for our roads Soils are used to absorb our domestic waste

Misuse of Soil l l Excessive timber cutting (erosion) Poorly maintained drainage areas Over tillage Excessive use of fertilizers

Available Land on Earth l l 13 billion hectares of land ½ is not suited for cultivation – – l l Mountains Dessert Ice Caps To Wet ¼ can support enough plant life for animals, but cannot be cultivated ¼ is suitable for cultivation – Of this about ½ is being cultivated