SCSC EXAM PRACTICE TEST 2024-
2025 QUESTIONS AND ANSWERS
100% VERIFIED
What influences chroma - Answer- -hematite (Fe2O3) makes soil redder
-goethite (FeOOH) makes soil yellower (OX)
-reduced iron (Fe2+) green/blue/gray (RED)
ID in a grouping of words, one or more words used in describing soil consistence -
Answer- describes resistance of soil to manipulation at a moisture level.
dry- loose, soft, hard
moist- friable, firm
wet-plastic, sticky
granular - Answer- (crumb)
most common in A hor.
pore space in aggregates from most to least (8) - Answer- most porosity
-structureless single grain
-crumb
-granular
-subangular blocky
-angular blocky
-prismatic
-platy
-structureless massive
platy - Answer- most common in A or E hor
angular blocky - Answer- common in B hor with higher amounts of clay
-almost 90 degree angles
sub-angular blocky - Answer- in A,E, and B hor. of little to moderate clay contenet
columnar - Answer- indicates Na on clays usually found in B horizons
prismatic - Answer- common in B horizons; often parts to angular or sub-angular blocky
structureless conditions - Answer- massive or single grain (beach sand)
typical structural description includes - Answer- grade, class, type
,-ex: weak, coarse, subangular blocky
grade - Answer- -weak- sandy, silty- easy to break when dry
-moderate- little pressure to break when dry
-strong- clays- hard to break when dry
class - Answer- very fine, fine, medium, coarse, very coarse
type - Answer- -structure type
-subangular blocky, crumb, granular, angular blocky, columnar, prismatic
hue - Answer- dominant reflected wave-length of light
-general spectral color
-ex: 10YR
-reddest to yellowest to greenest
-whole page in munsell color chart
value - Answer- light to dark
-quantity of light reflected
-2 to 8
-2=dark
-8= light
chroma - Answer- dull to bright
-purity of light reflected
-0 to 8
-0= dull
-8= bright
mottle - Answer- -colors mixed into matrix color
mixed colors due to OX (red and yellow)/RED (green, grey, blue)
-also called- redox features
-contracts matrix color
-described by amount, size, contrast, and color
matrix color - Answer- dominant color
-background color
how to read munsell soil chart - Answer- hue value/chroma
-ex: 10YR 5/4
given soil colors (word and munsell notation), name the soil constituent or soil condition
that could be responsible for the development of the color, and identify hue, value, and
chroma in the notation - Answer- ex: 10YR 5/4
hue=10Yr
value=5
, chroma= 4
yellowish brown= munsell color chart opposite page of hue.
-OM- makes soil darker
-moisture- makes soil darker
-oxidized Iron- hematite- red color
-hydroxide Iron- goethite- yellow color
-iron (ferrous iron)-grey, blue, green depending on degree of reduction
-iron 2+- ox highly limited- reduced condition
-white soils- uncoated quartz grains or Calcite, gypsum, or soluble salts
determine the dry mass of soil in pounds per acre (43, 560 sq, ft.) and in kilograms per
hectare when the bulk density and thickness of soil are given - Answer- (Area)(depth in
ft)( density of H2O)(BD)
soil aeration - Answer- O2 diffuses into soil (atmosphere has more)
CO2 diffuses into atmosphere (soil has more)
N2 is same in soil and atmosphere
-how well air will move from atmosphere to soil and vis versa
-well aerated soil is similar to atmosphere
mass flow - Answer- movement of air due to different total pressure
- total pressure atmosphere
-does not influence soil air into or out of soil that is a function of diffusion
diffusion - Answer- rate that gasses move due to difference in partial pressure
(differences in concentration)
-individual gas (O2, CO2, N2)
-partial pressure
-CO2 leaves soil O2 enters N2 is the same in both
what is O2 used for in soil - Answer- -root respiration
-microbe aerobic respiration
-inorganic OX reactions (such as OX of Fe) ex: Fe2+-->Fe3+
macropores - Answer- around aggregates
-water drains readily by gravity
micropores - Answer- within aggregates (interpedal)
improve soil aeration - Answer- -improve aggregation (Ca, OM)
-improve drainage
-tillage unless u create plow layer
-reduced soils are poorly aerated and OX soils are well aerated
well aerated soil oxidation reduction potential - Answer- movement of gasses meets
biotic req.
