Soils: Exam 2

Front 1

In the Soil loss equation define the symbols:
A= RKLSCP

Back 1

A: average annual soil loss
R: rainfall RUNOFF factor
K: soil erodability factor
L: slope LENGTH factor
S: slope STEEPNESS factor
C: COVER management factor
P: erosion control factor

Front 2

Factors that influence "K"
(soil erodability factor, normally ranging from 0- 0.6)

Back 2

stability if aggregates/organic matter
water infiltration rate
particle size

Front 3

How Does crop coverage help manage erodability?

Back 3

reduces surface puddles
intercepts rainfall
helps maintain infiltration rate
slows runoff
residue returned to soil influences soil structure
influences infiltration and permeability

Front 4

What are the support practices that comprise "P" of the universal soil loss equation?

Back 4

contour tillage
Contour strip cropping
Terracing

Front 5

What is conventional plowing?

Back 5

moldboard
% of surface residue very low

Front 6

Geologic erosion keeps up with the rate of _______.

Back 6

soil formation

Front 7

natural erosion is called ______

Back 7

geologic erosion

Front 8

Accelerated erosion is ____ to ____times greater than geologic erosion

Back 8

10x to 1000X

Front 9

Biggest causes of accelerated erosion?

Back 9

agriculture & grazing

in development when soil is often left bare for >1 year

Front 10

the greatest loss of soil nutrient is from ....?

Back 10

the removal of crops

Front 11

#1 water pollutant?

What effects?

Back 11

water sediments

disrupted water habitats
drinking water must be filtered
bad for recreation (suspicious looking & smelling)
navigation channels must be dredges
affects photosynthesis and plant growth

Front 12

What airborne pollutants can affect respiratory?

Back 12

clays ans silts can get deep into lungs

Front 13

Costs per year of wind erosion?

Back 13

8-40 billion on site
+
10-30 billion off site

Front 14

When sand skips along the surface and disrupts granular structure?

Back 14

saltation

Front 15

WEPP?

Back 15

Wind Erosion Prediction Program

uses climate, management, soil and topography to predict wind erosion

Front 16

WInd erosion accounts for ____of soil loss in the US.

Back 16

1/3

Front 17

windbreaks are good for....

Back 17

slowing wind velocity for 10x the height of the windbreak.

Front 18

3 steps in water erosion?

Back 18

detach
transport
deposit

Front 19

raindrop speed?

Back 19

30 km/hr or 20 mph

Front 20

USLE is used for _____erosion.

Back 20

Sheet and Rill!

Not gully!

Front 21

erosion where water moves in sheets and is hard to detect?

Back 21

sheet erosion

Front 22

erosion where small channels carve into soil surface?

Back 22

Rill erosion

Front 23

erosion where large channels are carved out and you need big machinery to correct it.

Back 23

Gully erosion

Front 24

T value is ....

Back 24

tolerable soil loss for a soil to remain productive indefinitely.
in tons/acre/year

Front 25

the physical condition of soil as it relates to plant growth?

Back 25

TILTH

Front 26

purpose of tillage?

Back 26

planting seeds

Front 27

when a rock sits on a "pedestal" of sand and silt as a result of raindrop erosion?

Back 27

pedestal deflation

Front 28

2 types of plowing that leave some litter undisturbed?

Back 28

chisel plow, disk

Front 29

conservation tillage leaves > ___% surface litter.

Back 29

30%

Front 30

what does seed bed prep do?

Back 30

prvent crusting, compaction
encourage water infiltration and pore space

Front 31

Steps in conventional tillage?

Back 31

moldboard plow + disk, drag, plant

Front 32

highest erosion from....

Back 32

fall plow

Front 33

fall plow causes highest erosion, tillage pan, platy to blocky structure, but benefits are...

Back 33

weed control, good seed bed prep, faster spring warm up

Front 34

is a dense layer beginning six to 10 inches below the surface

Back 34

tillage pan

Front 35

way to break up tillage pan?

Back 35

subsoiler- a chisel plow that vibrates deep in the soil and breaks it up.

Front 36

advantages of conservation tillage?

Back 36

reduce runoff
often comparable yields
less time and money
higher moisture retention

Front 37

disadvantages of "No till"

Back 37

slower spring warm up, evap
highest density/compaction
lowest pore space
heavier reliance on pesticides
hard to incorporate lime, fertilizers, manure, pesticides

Front 38

nutrients movement through soil is called...

Back 38

mass flow

Front 39

waters polarity good for transportation os ....

Back 39

cations and anions

Front 40

resistance to flow...

Back 40

viscosity

Front 41

adhesion and capillarity result in _____in soils.

Back 41

Matric tension

waters attraction to a solid

Front 42

SMT for OD soil

Back 42

-10K bars!

Front 43

SMT (Matric Tension) for air dry soil?

Back 43

-31 bars

Front 44

SMT for field capacity?

Back 44

-1/10 to -1/3 bars

Front 45

SMT at permanent wilting point

Back 45

-15 bars
plants have extracted all the water they can

Front 46

what is gravitational water

Back 46

between field capacity and saturation

Front 47

Plant available water is between

Back 47

field capacity and wilting point

Front 48

anions and cations conduct electricity to determine soil moisture in a ________.

Back 48

gypsum block

Front 49

device which send out fast neutrons and measures slow returning neutrons to accurately measure soil moisture

Back 49

neutron probe
(used in research)

Front 50

reflectivity
in also called....

Back 50

albedo

Front 51

process of warming soil deeper and deeper

Back 51

conduction

Front 52

units of volume heat capacity?

Back 52

cal/cm3 per 1 degree C

Front 53

air has a _____heat capacity

Back 53

low!

Front 54

water has a _____ heat capacity

Back 54

high