18

Question 1

Pedology

Answer 1

Origin, classification, distribution, and description of soil.

Question 2

Soil

Answer 2

Rock/sediment modified by physical and chemical interaction with organic material and rainwater, over time, supporting plant growth.

Question 3

Natural Factors (CLORPT)

Answer 3

Climate
◦ Organics (biology)
◦ Relief (slope steepness) and
topography
◦ Parent material (substrate
composition)
◦ Time

Question 4

The Human Factor

Answer 4

◦ Agricultural landscapes
◦ Nutrient loss through leaching
◦ Soil erosion

Question 5

Soil Profile

Answer 5

Vertical section of soil; surface to
bedrock (or roots end).

Question 6

Within a soil profile, soils
organized into distinct layers….

Answer 6

… O, A, E, B

Question 7

O Horizon

Answer 7

Mostly organic matter leaves, soil microorganisms
Forms humus
Able to retain water and nutrients

Question 8

A Horizon

Answer 8

Topsoil
Humus and clay particles provide essential chemical links between soil nutrients
Dark in color
Rich organic compounds

Question 9

E Horizon

Answer 9

Light in color
Composed of coarse sand, silt, resistant minerals

Fine particles removed by eluviation

As rainfall increases, so does the rate of eluviation

Question 10

B Horizon

Answer 10

Reddish or yellowish

Composed of accumulations of clays, aluminum, and iron by -illuviation-

Solum, true definable soil of the profile

Question 11

C Horizon

Answer 11

The deposit at Earth’s surface
from which the soil developed
Parent material
Plant roots or soil
microogranisms are rare

Question 12

R Horizon

Answer 12

Bedrock (e.g., granite, sandstone)
Could exist between <6 to 60 feet below topsoil

Question 13

Texture

Answer 13

Mixture of particle size and their
proportions.

Question 14

Loam

Answer 14

Balanced mixture good for
plants (sandy loam ideal for
agriculture b/c of its water holding characteristics).

Question 15

Structure

Answer 15

Arrangement of soil particles
(size and shape of aggregates).

Question 16

Peds…

Answer 16

…are the smallest lump or
cluster.

Question 17

Shape determines…

Answer 17

…structure.

Question 18

Voids or pores between peds
allow…

Answer 18

…moisture storage and
drainage.

Question 19

Consistence

Answer 19

The cohesion or consistency of soil particles
Soil’s resistance to breaking and manipulation with varying moisture

Question 20

Porosity & Moisture

Answer 20

Pores control water movement.
◦ Intake, flow and drainage
◦ Size, continuity, shape, orientation, location

Question 21

Soil moisture at field capacity results in…

Answer 21

…most efficient plant function.

Question 22

Chemistry

Answer 22

Pores can be filled with air, water, or a mixture of both.
◦ Chemical reactions

Question 23

Pores help combine…

Answer 23

…soil solution (water) with atmosphere (N2, CO2, O2).

Question 24

Chemistry results in…

Answer 24

…carbonic acid and various organic acids.