SCSC 301 STUDY GUIDE 2026/2027 QUESTIONS AND
SOLUTIONS RATED A+
✔✔The master horizons, arranged in order as they would occur from the surface
downward are: - ✔✔OAEBC
✔✔The mineral subsurface horizon in which organic matter accumulation is an
important microprocess is: - ✔✔Bhs
✔✔The formation of a __________horizon is due to the microprocess of illuviation of
clay into it. - ✔✔Bt
✔✔A horizon of eluviation indicates - ✔✔Zone of maximum leaching of clay and Fe/Al
oxides
✔✔Soils in arid to semi-arid climates, often - ✔✔have deposits of secondary minerals
that have formed from the weathering soluble components of primary minerals that
cannot leach and thus form secondary mineral deposits
✔✔Which of the following is acquired by soil forming processes rather than inherited
from the parent material? - ✔✔organic matter
✔✔Which of the subordinate descriptions is correct for an O horizon that is composed
of fibric material (i.e., slightly decomposed organic matter)? - ✔✔Oi
✔✔In a semi-arid to subhumid climate with grassland vegetation that is well developed,
you'd expect which horizon sequence? - ✔✔A1A2A3C
✔✔In a humid climate (eventually with forest vegetation), a soil will develop the
following sequences of horizons over time in this order_________ (youngest to oldest).
- ✔✔AC -> ABwC -> AEBt C -> AEBoC
✔✔This soil contains the only surface horizon that is not ochric - ✔✔A:
30cm, sandy clay(40%), crumb, high, OM% 1.2, 10YR 3/2, subsoil is clay(45%),
subangular blocky, high, smectite/slickensides
✔✔This soil has an endopedon that is most likely kandic - ✔✔C:
10cm, sandy loam(10%), granular, low, OM% 0.8, 10YR 6/4, subsoil is clay(50%),
blocky, very low, kaolinite
✔✔This soil is most likely an Inceptisol - ✔✔D:
10cm, silt loam(10%), granular, low, OM% 2, 10YR 7/2, subsoil is silt loam(10%),
subangular blocky, high, vermiculite/smectite
, ✔✔This soil is most likely an Entisol - ✔✔B:
30cm, loamy sand(5%), single grain, low, OM % 0.2, 10YR 7/3, subsoil is loamy sand
(5%), single grain, low, mica
✔✔This soil is most likely an Oxisol - ✔✔E:
10cm ,clay (45%), granular, low, OM% 2.5, 5YR 4/2, subsoil is clay(45%), granular, low,
Fe/Al oxide
✔✔ Which of the following is NOT a carbon-containing compound that is involved in the
cycling of carbon associated with most plant/animal life forms? - ✔✔calcium carbonate
✔✔Which organic matter property affects the availability of nutrients to plants? -
✔✔Cation exchange capacity
✔✔**Complete degradation of residues (complete oxidation) results in _______ -
✔✔CO2
✔✔Which of the answers below represents an immobilized form of N? - ✔✔protein in a
bacterial cell
✔✔Which is true when comparing aerobic vs anaerobic organic matter decomposition?
- ✔✔Anaerobic degradation is much slower than aerobic and results in compounds that
are partially decomposed
✔✔Soil organic matter degradation will be greatest when_____________ - ✔✔There is
sufficient soil moisture and aeration at neutral pH and relatively warm temperatures to
degrade residue with high levels of N
✔✔**Organic matter tends to decrease the ___ of soils. - ✔✔bulk density
✔✔**___ is the element in residue that has the greatest effect on the rate of residue
decomposition. - ✔✔nitrogen
✔✔**The organic matter content of soils tends to decrease with increasing frequency of:
- ✔✔cultivation
✔✔A soil with C/N ratio of 600:1 could be a material such as_______ - ✔✔sawdust or
leaves that have a low N content and a high potential for N immobilization
✔✔**Poorly defined organic substances that are complex, resistant to decay, and
polymeric are ___ - ✔✔humic substances
SOLUTIONS RATED A+
✔✔The master horizons, arranged in order as they would occur from the surface
downward are: - ✔✔OAEBC
✔✔The mineral subsurface horizon in which organic matter accumulation is an
important microprocess is: - ✔✔Bhs
✔✔The formation of a __________horizon is due to the microprocess of illuviation of
clay into it. - ✔✔Bt
✔✔A horizon of eluviation indicates - ✔✔Zone of maximum leaching of clay and Fe/Al
oxides
✔✔Soils in arid to semi-arid climates, often - ✔✔have deposits of secondary minerals
that have formed from the weathering soluble components of primary minerals that
cannot leach and thus form secondary mineral deposits
✔✔Which of the following is acquired by soil forming processes rather than inherited
from the parent material? - ✔✔organic matter
✔✔Which of the subordinate descriptions is correct for an O horizon that is composed
of fibric material (i.e., slightly decomposed organic matter)? - ✔✔Oi
✔✔In a semi-arid to subhumid climate with grassland vegetation that is well developed,
you'd expect which horizon sequence? - ✔✔A1A2A3C
✔✔In a humid climate (eventually with forest vegetation), a soil will develop the
following sequences of horizons over time in this order_________ (youngest to oldest).
- ✔✔AC -> ABwC -> AEBt C -> AEBoC
✔✔This soil contains the only surface horizon that is not ochric - ✔✔A:
30cm, sandy clay(40%), crumb, high, OM% 1.2, 10YR 3/2, subsoil is clay(45%),
subangular blocky, high, smectite/slickensides
✔✔This soil has an endopedon that is most likely kandic - ✔✔C:
10cm, sandy loam(10%), granular, low, OM% 0.8, 10YR 6/4, subsoil is clay(50%),
blocky, very low, kaolinite
✔✔This soil is most likely an Inceptisol - ✔✔D:
10cm, silt loam(10%), granular, low, OM% 2, 10YR 7/2, subsoil is silt loam(10%),
subangular blocky, high, vermiculite/smectite
, ✔✔This soil is most likely an Entisol - ✔✔B:
30cm, loamy sand(5%), single grain, low, OM % 0.2, 10YR 7/3, subsoil is loamy sand
(5%), single grain, low, mica
✔✔This soil is most likely an Oxisol - ✔✔E:
10cm ,clay (45%), granular, low, OM% 2.5, 5YR 4/2, subsoil is clay(45%), granular, low,
Fe/Al oxide
✔✔ Which of the following is NOT a carbon-containing compound that is involved in the
cycling of carbon associated with most plant/animal life forms? - ✔✔calcium carbonate
✔✔Which organic matter property affects the availability of nutrients to plants? -
✔✔Cation exchange capacity
✔✔**Complete degradation of residues (complete oxidation) results in _______ -
✔✔CO2
✔✔Which of the answers below represents an immobilized form of N? - ✔✔protein in a
bacterial cell
✔✔Which is true when comparing aerobic vs anaerobic organic matter decomposition?
- ✔✔Anaerobic degradation is much slower than aerobic and results in compounds that
are partially decomposed
✔✔Soil organic matter degradation will be greatest when_____________ - ✔✔There is
sufficient soil moisture and aeration at neutral pH and relatively warm temperatures to
degrade residue with high levels of N
✔✔**Organic matter tends to decrease the ___ of soils. - ✔✔bulk density
✔✔**___ is the element in residue that has the greatest effect on the rate of residue
decomposition. - ✔✔nitrogen
✔✔**The organic matter content of soils tends to decrease with increasing frequency of:
- ✔✔cultivation
✔✔A soil with C/N ratio of 600:1 could be a material such as_______ - ✔✔sawdust or
leaves that have a low N content and a high potential for N immobilization
✔✔**Poorly defined organic substances that are complex, resistant to decay, and
polymeric are ___ - ✔✔humic substances
