weathering and soil
Some organisms create passages for air and water to move into the soil, which speeds up weathering, and others aid in the decomposition of organic matter.
How do biota aid in soil formation?
By size.
How do scientists classify sediments?
Decomposition changes once-living material into organic matter.
How is decomposition related to organic matter?
The topsoil has more organic matter in it from the decay of organisms over time.
How is topsoil different from the subsoil?
Warm and wet climates.
In what climates are soils deeply weathered?
Young.
Is soil young or old after 1000 years?
No, soil can be transported away from its parent material and deposited on other bedrock.
Is the bedrock underneath a soil always the soil's parent material? Explain?
Layers of soil formed from the movement of the products of weathering. Each horizon has characteristics based on the type of materials it contains.
What are horizons?
sand, silt, and clay.
What are the 3 common particle sizes in soil?
Parent material, climate, topography, biota, and time.
What are the 5 factors of soil formation?
boulders, cobbles, gravel, sand, silt, or clay.
What are the sizes of rock fragments?
The amount of precipitation and average daily and annual temperatures.
What are the two measrues of a region's climate?
It mostly enters the soil.
What happens in a flat landscape to the water?
It flows fast downhill and increases weathering.
What happens in steep lanscapes to the water?
Pore size is larger if particle size is larger.
What happens to pore size as particle size changes?
The remains of something that was once alive, plant or animal.
What is Organic matter?
Small holes and spaces in soil.
What is a pore?
The average weather of an area.
What is climate?
The hardness or softness of a soil. It varies with moisture. Some soils have a soft slippery consistency when they are moist but dry and hard when dry.
What is consistency?
The process of changing once-living material into dark-colored organic matter. It is how organic matter is formed.
What is decomposition?
Weathered rock or rock broken into tiny peices.
What is dust?
Measure of the ability of a soil to support plant growth. Includes the amount of certain elements.
What is fertility?
How fast water enters soil.
What is infiltration?
Things that have never been alive.
What is inorganic?
Acidic or Basic or neutral. Acid = 0-6, Basic = 8-14 neutral =0
What is pH?
The amount of water in soil pores is moisture content.
What is soil moisture?
The shape of soil clumps and how the particle hold together. It can look grainy, blick, or prism shaped.
What is soil structure?
Soil is a mixtore of weathered rock, rock fragments, decayed organic matter, water, and air.
What is soil?
Top layer with organic matter from deay of roots and soil organisms. Excellent for plant growth. Darker
What is the A-Horizon?
Water from rain or snow seeps throug pores in the A-horizon, it carries clay particles. The clay is deposited below the upper layer, forming a B-horizon. More dense.
What is the B-Horizon?
Weathered parent material. Parent material is rock or sediments.
What is the C-Horizon?
All the organisms that live in a region.
What is the biota?
Sediment is weathered rock and soil is a mixture of sediments, decayed organic matter, water,and air.
What is the difference between sediment and soil?
The starting material of soil. Made of rock sediment that weathers to form soil.
What is the parent material?
The shape and steepness of the landscape.
What is topography?
Weathered rock fragments, water, and air.
What part of soil is inorganic?
Soil's texture, structure, and infiltration affect how much water can pass through it.
What properties give an indication of the soil's ability to allow water to pass through it?
topsoil because this is where animals and plants carry on their activities.
What soil layer is affected most by bioa?
Soil texture, organic material, and pH.
What soil properties are related to fertility?
pH and nutrient content, soil moisture, fertility, temperature, and infiltration.
What soil properties can be measured in a lab?
color, texture, structure, consistency
What soil properties can be observed?
Weathering and decomposition or organic matter constantly change soil.
What two processes constantly change soil as it forms?
Humid climates can cause soil to become more acidic.
What type of climate causes soil to become more acidic?
Low moisture content, sandy texture, little organic material.
What type of soil is found in a desert?
When the A-horizon is carried away by weathering.
When is soil made of only 2 horizons?
A soil that is made up of silt and clay sized particles would swell more because smaller particles help the soil retain more water.
Which soil would sell the greatest amount after a rain? One that is made of sand and silt sized particles or one that is made up of silt and clay sized particles? Why?
Rocks are subjected to faster rates of chemical weathering due to warm temperatures and chemical reactions with water.
Why do soils form rapidly in warm, moist climates?
If freezing and thawing do not occur, then the ice wedging and thermal expansion don't occur. If the water just remains frozen, then it doesn't dissolve into the water and cause weathering.
Why do soils that remain frozen throughout the year have a simple structure?
Organic material is dark and dark absorb heat from the sun. Organic matter holds water and provides plant nutrients. It holds minerals together in clusters and helps keep the soil pores open for the movement of water and air in soil.
Why is organic material in soil important?
Pores let water flow into and through soil. The larger the pore size, the more water can flow into and through soil.
Why is pore size important?
The pressure and weight of the layer on top and there is no plants or animals to loosen the soil down below.
Why is the deeper soil layers more tightly packed?
They change from place to place because of parent material, climate, biota, and topography.
Are soils the same everywhere?
Yes, frequent freezing and thawing can cause rocks to undergo ice wedging and thermal expansion and contraction.
Does frequent freezing and thawing increase the rate of weathering?
