Unit 1 Flashcards
Munsell Color Chart
A chart consisting of color chips. Color chips are arranged based on HUE, VALUE, and CHROMA.
Ped
aggregate of soil particles that display characteristics of that soil sample
hydration
a process in while intact water molecules may bind to a mineral
pedon
smallest sampling unit that displays the full range of properties characteristic of a particular soil
Tilth
the ease with which the soil is tilled
Texture/Soil Texture
describes the size of the soil particles
Soil structure
describes the manner in which the soil particles are aggregated
Micropore
Usually filled with water. Even when not filled with water, they are usually too small to permit much air movement
metamorphic
formed from other rocks by a process of change called metamorphism. happens when the earth’s plates shift and collide
Sedimentary
form when weathering products released from other, older rocks collect under water as sediment and eventually form a new rock
An ideal handful of soil has:
25% air
25% water
45% mineral matter
5% organic matter
regolith/solum
the rock exposed at the earth’s surface with has crumbled and decayed to produce a layer of unconsolidated debris overlaying the hard, unweathered rock.
Soil horizons
contrasting layers in the soil
soil pit
a large hole, several meters deep and about a meter wide, to study soil horizons
soil profile
The vertical section exposing a set of horizons in the wall of the soil pit
topsoil
the organically enriched A horizon at the soil surface
subsoil
soil layers that underlie the top soil
humus
usually black or brown. a collection of organic compounds that accumulate in the soil when partially broken down plant and animal residues are protected from complete decay by various factors in the soil environment
Acidic Soil
Soil measurement below pH 7
Alkaline soil
soil measurement above pH 7
Neutral Soil
soil measurement of 7
Hydrolysis
A reaction with water that splits the water molecule into H+ and OH- ions
dissolution
process by which molecules of a gas, solid, or another liquid dissolve in a liquid, thereby becoming completely and uniformly dispersed throughout the liquid’s volume
oxidation reaction
occurs when an atom, molecule or ion loses one or more electrons. Example: iron rusting
Vadose Zone
the aerated region of soil above the permanent water table
aggregate
many soil particles held in a single mass or cluster, such as a clod, crumb, block or prism
Particle density
the mass per unit volume of soil particles
macropore
larger soil pores, from which water drains readily by gravity
microorganism
bacteria, fungi, algae, protozoa and actinomycetes that live in the soil. Most bacteria, fungi and algae are helpful.
macroorganism
consist of arthropods, mollusks, and nematodes in the soil
peat
unconcolidated soil material consisting largely of undecomposed, or only slightly decomposed, organic material accumulated under conditions of excessive moisture.
exfoliation
peeling away of layers of a rock from the surface inward, usually as the result of expansion and contraction that accompany changes in temperature
loess
material transported and deposited by wind and consisting of predominately silt sized particles
slope
the degree of deviation of surface from horizontal, measured in a numerical ratio, percent or degrees
soil taxonomy
fill out later
epipedon
a diagnostic surface that includes the upper part of the soil that is darkened by organic matter, or the upper eluvial horizons, or both
colloid
organic and inorganic material with very small particle size and a correspondingly large surface area per unit of mass
illuviation
the process of deposition of soil material removed from one horizon to another in the soil; usually from an upper to a lower horizon in the soil profile
master horizon
A,B and C are master horizons. they are the largest chunks found in a soil profile, and all other horizons are subcategories or mixtures of them
eluviation
The removal of soil material in suspension or in a solution from a layer or layers of a soil. Usually, the loss of material in solution is described by the term ‘leaching’.
topography
the arrangement of the natural and artificial physical features of an area
What is an ideal soil?
Loam
What are the 3 major particles of soil mineral matter?
sand, silt, clay
What are the 6 key roles of soil?
- medium for plant growth
- recycles nutrients
- habitat for organisms
- purifies water
- gas exchange
- engineering medium (build on it)
What are the 16 elements essential for plant growth?
C. HOPKNS CaFe Mg B Mn CuZn MoCl(xcl) NiCo
What are the 4 major components of soil?
air, water, organic matter, mineral matter
What is in the ideal handful of soil?
25% air,
25% water
45% mineral matter
5% organic matter
How does climate affect development of organic matter?
warmer temperatures accelerate decomposition and soil processes. Too hot or too cold, organic matter is not efficiently developed.
soil water
water found in naturally occurring soil
relationship of soil air to soil water?
a balance between soil air and soil water must be maintained since soil air is displaced by soil water. air can fill soil pores as water drains, air moves out of pores as water enters.
How do the arrows run on a soil texture triangle? think about it, and then flip card. do you know how to use a soil texture triangle?
clay: horizontal from left to right
Silt: diagonal toward center from top to bottom
sand: diagonal going toward clay side, from bottom to top.
How do texture and structure influence water holding capacity
Smaller particles (silt and clay) have a larger surface area. They are able to hold more water with their surface area. Larger particles (sand) do not hold water very well
What does “x” in a soil profile mean?
fragipan
What does “p” in a soil profile mean?
plowed
What does “Ap” in a soil profile mean?
an A horizon that has been plowed
What does “t” mean in a soil profile?
silicate clay
How does temperature affect chemical reactions?
HEAT speeds up reactions!!! too hot or too cold = little to no chemical reaction
How does slope affect a soil profile?
There could be little to no topsoil in an area with a large slope. When a large slope is present, larger aggregates and rocks tend to rise to the top.
What are the factors that control soil formation?
Destructive processes
- due to mild acids
- temperature fluctuation
- pressure
- wetting and drying
Creative
- freezing and thawing mixes soils together
- formation of new minerals and new clays
