Term
| Benefits of vegetation along streams |
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Definition
-Grasses best on banks
-Trap sediment transported from streams
-Make streams deeper/narrow
-Problem w/ trees is they are big & die, fall in stream destabalizing & causing turbulence.(Large woody debris) |
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Term
Measurements of Area:
-Acre in feet
-Mile in acres
-Hector in acres
-Kilometer:Miles
-Mile:kilometers |
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Definition
-Acre:43,560sq ft(size of football field including sidelines.
-Mile: 640acres
-Hector: 2.5 Acres
-Kilometer: 0.62 Miles
-Mile: 2.7 km sq |
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Term
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Definition
| Particle size, sand,silt or clay? determines acquisition, retention, transmittion of water. |
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Term
| How are "peds" held together? |
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Definition
| electrochemical bonds & organic gels- they allow for more aeration of water/air, root system growth, porosity. |
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Term
| What is rock gravity density? |
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Definition
| 2.7 jules, soil is about 1/2 rock so around 1.35 jules. |
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Term
| How much does a cubic ft of water weigh? Soils? |
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Definition
| Water=62.4lbs, soil=90lbs |
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Term
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Definition
Alluvium= material along streambanks.
colluvium= material accumulating on hillsides, didnt make it down to streams. |
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Term
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Definition
| wind deposited accumulation |
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Term
| What are some soil forming factors? Clorpt equation! |
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Definition
-Climate:MOST IMPORTANT, water makes all chem. & physical reactions possible, too much water= leaching.(30 inches is best amount!), temperature, and wind.
-organisms, includes humans
-relief: the terrain: sunny/shady sides, flood plains etc.
-Parent Material
-TIME |
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Term
| What is podzolization and where does it occur? |
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Definition
| Podzolization= Soils stripped of most nuitrients, white soil: spodisols; occurs in humid regions with excess water. |
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Term
| Why are there no forests in the midwest? |
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Definition
| Indians burned them all down. |
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Term
| How did prairies grow in the west? Not enough precipitation. |
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Definition
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Term
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Definition
-Sheet: raidrops have large impact when hit move layer of topsoil.
-Rill: gullies small enough to move over.
-Gully: large channels, too big for vehicles to move over
-Stream erosion |
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Term
| Problems of erosion in water |
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Definition
-lost productivity, decrease in aggregates
-exposure of subsoil/loss of topsoil/lack infiltration, fertility.
-Sediment is greatest pollutor of water in world; fills harbors/rivers, costly to dredge; chokes out fish |
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Term
| What is terminal velocity? |
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Definition
-30feet
More intense the rain/greater size of raindrops= closer to terminal velocity
-Can be decreased by vegetation: directly- interception of leaves, can increase effects in tall canopies, forming very large raindrops easier to reach terminal velocity. |
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Term
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Definition
| earthworms, ants, termites, bugs, moles, etc. |
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Term
| Structure on effects of raindrops |
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Definition
-Very powerful: Well structured soil can prevent.
-Cementing material
-organic gels
-minerals(calcium carbonate)
-Clay
-CEC |
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Term
| What are some wind erosion factors? |
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Definition
-Preponderance: Direction wind is coming from, just one or multiple?
-Soil structure: strong aggregates, anything larger than 1mm won't move.
-Surface ridges(furrows): tilled land into ridges reduce velocity, BUT must be correct, can create turbulence if incorrect and increase erosion in tunnels.
-Length of field: longer the stretch, more the erosion
-avalanching: long area creates "Fetching"= creation of waves like that of a deep ocean= more velocity and grip it gets. As soil moves downwind it usually more smooth the further down.
-Vegetative cover: more cover= more windbreak.
-Keep land wet and it wont erode from wind! avoid wilting point!(15 bars) |
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Term
| Who creates soil surveys? |
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Definition
Natural resources Conservation Services.
-started in 1899, mapped soils directly on topography.
-1950-70's, got mucher better: showed land best for farming, urban development, etc.(class 1_) & land not even good enough to walk on (class 8) |
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Term
| Factors of soil structure: Clay, organic |
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Definition
-Clay: upto 40% clays in soil is beneficial more than that is not.
-Organic material @ a certain concentration can be adverse. |
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Term
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Definition
-Most erosion occurs on banks of streams when wet, water aquires pore pressure, breaks off easily.
-Floodplains: Usually don't erode, low slope lots of vegetation.
-Wetter then bank, less the strength
-Grazers can can erode through hooves or eating vegetation on banks. |
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Term
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Definition
| Rocks stored along streams to prevent erosion. |
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Term
| What grains get lost in stream erosion? |
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Definition
-Sand is most easily eroded, not large enough to resist or small enough for cohesion.
-Clay: once loses cohesion, lost in water indefinately. |
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Term
| What are the factors of stream power? |
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Definition
-Density: sediment load(minor role)
-Velocity
-Depth: deeper the water more the power.
-multiply all together to find power. |
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Term
| What is avg soil loss tolerance? |
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Definition
2-5 tons/acre-year(T-FACTOR)
--1 ton= 200lbs
-Soil regenerates 1 inch/century! |
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Term
| What are some tolerance factors(T-factors)? |
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Definition
Depth of existing soil
type/depth of parent material
fertility of subsoil- always less fertile than topsoil |
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Term
| What is the universal soil loss equation? |
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Definition
| Annual soil loss= rainfall*soil erodibility*angle of slope*length of slope*vegetative cover*conservation.(last two are cultural factors, changable) |
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Term
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Definition
suspension: 1/2 mm & smaller suspended in air, can move 1000's of miles.
Saltation: 1/2 mm and up, bouncing across landscape.
surface creep: 1 mm & larger |
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Term
| Major problems of wind erosion |
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Definition
-fine particles sorted & carried off which can cause major loss of nuitrients.
-Abrasion of plants & materials
-air pollution
-deposition. |
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Term
| What are some factors to crop cover under the annual soil loss equation? |
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Definition
C= crop factor obtained from percent of rain that strikes vegetation before falling on soil surface(Crop canopy), prior land use, surface cover & surface roughness.
X= slope. |
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