Soil Science Q1 Flashcards
Biopore
Pore space created by organic matter
Macropore
Pore that is >0.8 mm
Usually filled with air
Soil Taxonomy
The science of classifying soil based on profile characteristics and best use
What are the levels of soil taxonomy?
Order, suborder, great group, subgroup, family, series
Mircopore
Pore that is <0.8 mm
Usually filled w/ water, as it’s too small for air
Slows water and air movement
Porosity
Percent of a soil sample that is pore space
Does pore space increase or decrease deeper in soil?
How does the air:water ratio change?
Pore space decreases
More water and less air
Soil Mulch
Shallow tillage of the soil to reduce evaporation and maintain nitrogen levels
Only useful with shallow water tables
Fallow
Land that is left uncultivated for a growing season to build water stores in soil
Tillage
Mechanical stirring of the soil (usually topsoil) to increase plant growth
Soil Tilth
Physical condition of soil as it relates to tillage and plant production
What 8
factors affect soil tilth?
structure, texture, organic matter, bulk density, pore space, aeration, water content, nutrient content
Bulk Density
Mass of a unit of dry soil (physical content and pore space, but no water)
Dry soil mass (g)/volume (cm^3)
High bulk density makes tillage and root growth difficult
What three things does soil structure affect?
Water/air movement, plant growth, and heat transfer
What are the two types of structureless soils?
Massive and single grain
Percolation
Downward movement of water through soil
How many soil texture classes are there?
12
Coarse Fragments
Any particle larger than 2mm
Not considered part of the soil
Ped/Agregate
A shape of soil structure
What are the six soil structures?
- Granular
- Platy
- Angular blocky
- Sub-angular blocky
- Prismatic
- Columnar
Diagnostic horizon
The presence or absence of a soil horizon
Epipidon
A diagnostic horizon taken from the topsoil
Section
1 square mile, or 640 acres of land
1/36 of a township
Began measurement in NE corner and worked their way over and down, alternating E/W starting point with each row
What are the 12 orders of soil and the suffixes used for their suborders??
Alfisol (-alf)
Andisol (-and)
Aridisol (-id)
Entisol (-ent)
Gelisol (-el)
Histisol (-ist)
Inceptisol (-ept)
Mollisol (-oll)
Spodisol (-od)
Ultisol (-ult)
Vertisol (-ert)
Oxisol (-Ox)
Alfisol (-Alf)
(5 characteristics)
Soil order
-light in color
-moist
-shallow
-slightly acidic
- Vulnerable to erosion
Often found in deciduous forests
Andisol (-And)
(3 Characteristics)
Soil order
- Volcanic
- Young (5k-10k years old)
- Little profile development
Good for growing wheat
Commonly found in NW U.S., Hawaii, Alaska
Aridisol (-Id)
(2 Characteristics)
Soil Order
- Lacks moisture most of year
- Accumulations of calcium carbonite, gypsum, and sodium
Found in arid and semi-arid areas, esp. in Western U.S.
Entisol (-Ent)
(4 Characteristics)
Soil Order
- Little no no profile development
- Sandy
- Rock Close to surface
- Usually alluvial parent material
Commonly found in Rocky Mountains
Gelisol (-El)
(4 Characteristics)
Soil Order
- Layer of permafrost
- Young soil
- Little to no profile development
- Cryoturbation (movement from freezing/thawing)
Found in Alaska
Histisol (-Ist)
(1 characteristic)
Soil Order
- >20% organic matter
Very productive once drained
Found in wetlands, Florida, Canada, coast
Inceptisol (-Ept)
(3 characteristics)
Soil Order
- Begining profile development
- Close to parent material
- Clay accumulation
Found throughout U.S. , especially in the NE and Alaska
Mollisol (-Oll)
(3 Characteristics)
Soil Order
- Dark prairie soil
- Accumulations of organic matter and carbon
- Very fertile
Best soil for agriculture, commonly used to grow vegetables and flowers
Commonly found in the midwest, great plains, E Washington/Oregon, and N Illinois
Spodisol (-Od)
(4 Characeristics)
Soil Order
- Wet, acidic soil
- Presence of E horizon
- High organic matter content
- High iron oxide content
Not naturally fertile, but can be made so artificially
Found in cold, wet areas, coniferous forests, Canada and NE U.S.
Ultisol (-Ult)
(4 characteristics)
Soil Order
- Older, more developed soil
- Acidic
- Few available plant nutrients
- Resistant to erosion
Can be productive, but requires lots of maintenance
Found in subtropical forests
Vertisol (-Ert)
(4 characteristics)
Soil Order
- Swelling clay
- Dark in color
- Cracks when dry
- Sticky
Can be very fertile
Problem for engineers due to movement and stickiness
Found in semiarid and subhumid areas, warm places with long dry seasons
Oxisol (-Ox)
(5 Characteristics)
Soil order
- Weathered
- High concentrations of iron oxide and aluminum oxide
- Moderately Acidic
- Resistant to erosion
- Not particularly fertile
Found in hot climates, such as Hawaii and Puerto Rico
Most common orders of soil in Oklahoma
Mollisols
Ultisols
Alfisols
What is the order soil horizons are found in?
O A B E C R
O Horizon
Organic Matter on the top of the soil
(Optional layer)
A Horizon
Topsoil, mix of minerals and organic matter
Most living things in soil found here
E Horizon
Leached layer consisting of erosion-resistant sand and silt (e.g. sodium or quartz)
Often found in old soils and soil in forests
(Optional layer)
B Horizon
Subsoil, mineral-rich soil, often composed of clay and heavily influenced by climate
C Horizon
Young soil made of unconsolidated parent material
R Horizon
Bedrock
Parallels
Lines of Latitude
Latitude parallels of the North and South poles
90* North Pole
-90* South Pole
Meridians
Lines of Longitude
Town Prime meridian passes through and why
Greenwich, England
Developed when England was a world power when Prime Meridian established, and Greenwich had an observatory
Latitude of equator and longitude of prime meridian
0*
Metes and Bounds system
Legal land description system developed by colonial-era Europe, based on physical characteristics of land
Rectangular System
Modern land distribution system developed by U.S. public land survey
Divided land into equally-sided rectangles
Principal Meridians used to divide Oklahoma via Rectangular System
Indian Meridian (Everything but panhandle)
Cimarron Meridian (Panhandle)
Township
A 6mi X 6mi area of land
36 sq. miles
Alluvial/Alluvium
Parent Material
Deposit of sediment left by fast-flowing water
Lacustrine
Parent Material
Deposit of sediment left in the center of slow-moving water (e.g. lake)
Colluvial/Colluvium
Parent Material
Sediment deposited by gravity
Eolian
Parent Material
Sand deposited by wind erosion
Loess
Parent Material
Silt deposited by wind erosion
Quarter
160 acres,1/4 sq mi
one-quarter of a section
Can also be a quarter of a quarter, or 40 acres
Or a quarter of a quarter of a quarter, or 10 acres
It’s turtles all the way down
Glacial Till
Parent Material
Sediment deposited by movement of glacial ice
Characterized by wide variety of sediment from many locations, as well as moraines (ridges)
Glacial Outwash
Parent Material
Sediment deposited by melted glacier water
Highly stratified
Residual/Residuum
Parent Material
Sediment found in the location formed
Organic Deposits/Peat
Parent Material
Sediment formed by decomposed organic matter
What are the nine parent materials?
- Alluvium
- Lacustrine
- Colluvial
- Glacial Till
- Glacial Outwash
- Eolian
- Loess
- Residuum
- Organic Deposit
Estimated global population by 2050
9.1 billion
Estimated percentage by which food production will have to increase to maintain population by 2050
70%
Soil Health
The fitness of soil for any of 3 different functions
- medium for plant growth
- environmental buffer
- enhancing health of plants and animals
Soil Quality
The capacity of a soil to function within its ecosystem boundaries to promote biological productivity and diversity
Indicator
A property of soil that is used to assess soil health and soil quality
What are the ten indicators used to rate soil?
- Texture
- Depth
- Bulk density
- Water holding capacity
- Soil organic matter (SOM)
- pH
- Extractible nitrogen, phosphorus, and potassium
- Microbial biomass
- Specific Respiration
- Macroorganism quantity
Ephemeral Indicator
An indicator that can be changed
Intermediate Indicator
An indicator that can be slightly changed
Permanent Indicator
An indicator that cannot be changed
What six steps can we take to increase soil health?
- Soil cover
- Live root system
- Grazing animals
- Minimizing tillage
- Biodiversity/crop rotation
- Water management
What three factors can cause soil health to continue to decline?
- Population/economy demand
- Extent of demand
- Lack of global determination to stop environmental degredation
Intensified Agroecosystems
Management systems that led to increased food production when the population exploded
What were four benefits of intensified agroecosystems?
- Increased plant production per sq. mile
- Increased content of N, P, and K
- Increased crop residue left in soil
- Decreased pressure on fragile land
What were seven drawbacks of intensified agroecosystems?
- Nutrient deficiency
- Excess nutrients
- Decreased pH
- Irrigation-induced salinization
- Overapplication of chemical pesticides
- Decreased biodiversity
- Increased rate of plant disease
The three types of soil texture
- Sandy
- Loamy
- Clayey
Munsel Color Book
A book used to precisely identify the color of soil
