Soil Flashcards
Soil is actually quite a ______ _______.
complex substance
What does soil support?
It supports plants, holds water, and brings us food.
What is soil made up of?
Made up of disintegrated rock, broken down organic matter, gas, water, nutrients, and biological organisms.
1 teaspoon of soil can contain up to….
100 million bacteria, 500,000 fungi, 100,000 algae, and 50,000 protists.
What kind of resource is soil?
A renewable resource, but slowly regenerated.
Because of the diversity, soil is actually considered a
micro-ecosystem
Soil starts with
Parent Material
Parent Material
the geological material that breaks down and forms sediment.
Parent Material could be ______
mountainous rock, lava, sand dunes, glacier, river sediment, or bedrock
Parent Material is broken down by either
chemical or physical processes called weathering.
The weathering of parent material is just the ____
first step of soil formation
Types of weathering
Wind, Rain, and Chemical
The second step of soil formation is the movement of particles from one location to another called _______
erosion
Once broken down and carried away…
rock debris will combine with organic matter, microbes, and other materials to form soil.
Soil will exist in different ________, or layers
horizons
What are the different horizons?
O horizon, A Horizon, B Horizon, C Horizon
O horizon
Organic litter layer
A horizon
Topsoil
B horizon
Subsoil
C horizon
Parent material
The smaller the topsoil, the less amount of
plants
Topsoil is
the most important layer with respect to plants as this where they gain their nutrients and food from. The nutrient content, ability to hold water, and depth will ultimately determine how well a plant will grow.
Organic matter _____ as you travel down the horizons
decreases
Leaching
The movement of nutrients through layers
There are __ classifications of soil that soil scientists use that derive from where they originated.
12
Soil color
can sometimes indicate fertility
if it has a lot of oxygen, it will be red
the darker the soil, the more nutrients
Soil texture
Size of parent material particles
Soil structure
the ‘clumsiness’ of soil
how well does it hold up
Soil pH
the acidity of soil
pine trees make soil acidic
Mollisols
located in great plains, rich in nutrients
Ultisols
located in Deciduous forests, are strongly leached, acid forest soils with relatively low native fertility
Ardisols
located in deserts, contain CaCO3-, limited leaching, dry
Oxisols
located in intertropical regions in the world, highly weathered soil
Vertisols
located in Denton, Texas and Mississippi river, heavily clayed that gets cracks in the soil, river bed soil
Soil Texture consists of three categories
silt, sand, and clay
Ultimately soil is affected by its
regional characteristics
Some areas allow for more ______ ________
cation exchange
Cation Exchange
how plants uptake nutrients
What makes for better cation exchange?
Finer texture and more organic matter
Who was better soil? The Amazon rainforest or the Kansas plains?
The Kansas Plains
Different soils in Denton county are:
Blackland Prairie (black) on the East Cross Timbers (reddish brown) at Ryan HS Grand Prairie (white/gray) - on the West
______ is a huge problem in American agriculture. Almost equally as important is ______, or the arrival of the eroded material at a new location
Erosion; deposition
Erosion generally happens ______ than soil formation can occur
faster
How have we increased erosion?
through over cultivating fields, overgrazing rangelands, and clearing forests.
What are the types of soil erosion?
Splash Erosion: from a constant drip, irrigation, one spot getting hit by a raindrop.
Gully Erosion: Dry river beds
Rill Erosion: Eroding on elevation
Sheet Erosion: low lying area that collects water that doesn’t go away (almost only happens in TX)
After a long time of erosion, the end product is the removal of ______ and loss of _______ __ ________
topsoil; nutrients of plants
As this happens, plants and vegetations die, driving….
erosion even deeper.
Desertification
the process of an area becoming more and more like a desert.
Crop rotation
only farm at a certain part of your land at a time
Contour farming
fitting your fields around your topography
Terracing
Take a hillside but because it’s too steep you cut away at the mountain
Shelterbeds
surround land by trees
Intercropping
planting different species of plants in the same place
No-till farming
every planting season people saves soil
Irrigation
Watering crops artificially
Over-irrigation can deposit
salt and excess nutrient sediments on the soil’s surface as the water evaporates.
Salinization
over time the build up of salt levels on the surface causes this process, that ultimately kills plants. In order to stop salinization, don’t overwater.
