SOILS How Do Soils Form Soils differ from

SOILS

How Do Soils Form? • Soils differ from one part of the world to another • Differ because of where and how soil was formed • There are 5 major factors that control how a soil forms …CLORPT

CLORPT • 5 Formation Factors: Climate Organisms Relief Parent Material Time CLORPT for short!!!

CLIMATE • Temperature and moisture influence the speed of chemical reactions • This controls how fast rocks weather and dead organisms decompose • Temp. increase = weathering increase • Rain/water increase = weathering increase

ORGANISMS (Vegetation and Biology) • Plant roots spread out, animals burrow, and bacteria eat… this speeds up the break down of soil particles • Roots give CO 2 and organic kjskjss acids that break down • Roots may physically break hjjjjjh rocks • Decomposers such as fungi, jhjjjjjjjjjj worm, and bacteria

RELIEF (Topography) • Shape and aspect (direction the land faces) makes a difference in the how much the sunlight the soil gets and how much water it keeps • Steep slopes are more likely to erode and are unstable • Sun facing slopes show more development as they are warmer • Deeper soils form at the jjjjjjjj bottom of a hill due to water jjjjjjjjjjjjjj and gravity

PARENT MATERIAL • Every soil inherits traits from the material from which it formed… just like you! • EXAMPLES • Soils formed in limestone bedrock are high in calcium • Soils formed at the bottom of lakes are high in clay • Parent material can include – Transported Materials – Bedrock or Residual Materials – Organic Materials

TIME Older soils differ from younger soils Have had more time to develop More horizons Time does not always represent true chronological order • EXAMPLE • • • Old soil in Antarctica will show very little development and appear young • Young soil in a tropical area will show more development and appear older