What makes one soil different
Each soil tells a different story of its origins and management
practices. On soilsmatter.wordpress.com,
Eric Brevik at Dickson State University, North Dakota, points out
that these differences are the result of five factors. He refers
to them as ClORPT: climate, organisms, relief, parent materials
- Temperature and precipitation are the main factors making soils
different from one another.
- Precipitation dissolves minerals and salts in the soil. These
move with the water down through the soil profile.
- Climate and temperature also influences which plants and other
organisms live in the soil.
- Animals and microorganisms living in soil decompose plant and
animal tissues, and wastes. Eventually these become humus which
influences soil color.
- Organisms and humus also affect and the size and shape of the
clumps of soil particles, called peds.
- Peds are important because that is what makes a soil's structure.
- Where a soil is found in the landscape relief or topography
affects its characteristics.
- Soils on slopes, for example, often experience more erosion
and thus are shallower than soils on the top of a hill. Soils
at the bottom of the slope are often much deeper due to the deposition
of the eroded soil from the slope above.
- A soil's position in the landscape can also indicate its inherent
drainage (well, imperfect or poorly drained).
- Soils develop from parent materials including minerals and rocks.
- Some soils form directly over bedrock but others develop from
the materials transported and deposited by glaciers, gravity,
wind, rivers, lakes, or oceans.
- These materials give soils their properties including particle
size and minerals.
- The minerals contribute color and influence chemical factors
that affect pH and nutrient availability.
- All soil-forming processes take time.
- Younger soils are typically shallower and often more fertile
than older soils. It takes less time for a soil to form in sediments
deposited by wind than from bedrock because plants can readily
grow in sediments. Bedrock has to weather first into soil-sized
As you look at different soils in a pit or a trench, think about
how ClORPT factors gave them their character.
For other interesting posts about why soils matter visit: soilsmatter.wordpress.com