Definitions

Question 1

topsoil

Answer 1

organically enriched, majority of plant roots found here

Question 2

subsoil

Answer 2

where most water is stored, roots can’t really grow here, it’s hard to modify subsoil

Question 3

disintegration caused by temperature, water, wind, ice, and organisms.

Answer 3

physical weathering

Question 4

> 0.08 mm diameter, earthworms and small organisms can move through, water can move through

Answer 4

macropores

Question 5

< 0.08 mm diameter, hold water so tightly plants can’t access it

Answer 5

micropores

Question 6

the hydrogen don’t attach to the water evenly, they make a v-shape instead and this causes the positive charges to cling towards the side weighed down with the two hydrogens therefore causing this property of water

Answer 6

polarity

Question 7

one of the hydrogens makes a low-energy bond to an oxygen particle from another molecule of water. this causes water to have a higher boiling point, specific heat, and viscosity

Answer 7

hydrogen bonding

Question 8

the attraction of water molecules for each other

Answer 8

cohesion

Question 9

the attraction of water molecules for solid surfaces, causes some water molecules to be held rigidly at the surface of soil solids

Answer 9

adhesion

Question 10

results from the greater attraction of water molecules for each other than for the air above, causes an inward force at the surface

Answer 10

surface tension

Question 11

force caused by adhesion, reduced the energy state of water near particle surfaces

Answer 11

Matric

Question 12

force caused by cohesion, reduces energy state of water in the soil solution

Answer 12

osmotic

Question 13

force pulling the water downward

Answer 13

gravimetric

Question 14

process by which water enters the soil pore spaces and becomes soil water, takes place at the soil surface

Answer 14

infiltration

Question 15

process by which water moves downwards into the soil profile, rate is related to the soil’s hydraulic conductivity

Answer 15

percolation

Question 16

when water addition stops the largest pores will drain downward rapidly, when this flow becomes negligible the soil is holding the maximal amount of water useful to plants

Answer 16

field capacity

Question 17

all soil pores are filled with water, matric potential is close to zero, the soil will remain here only so long as water continues to infiltrate

Answer 17

maximum retentive capacity

Question 18

the rate of plant water removal fails to keep up with the plant needs so the plant wilts

Answer 18

wilting coefficient

Question 19

soil moisture is lowered below the wilting point, the water molecules that remain are very tightly held, most are absorbed by colloidal soil surfaces the water is held so rigidly that most of it can only move in the vapor phase

Answer 19

hygroscopic coefficient

Question 20

an area of land drained by a single system of streams and bounded by ridges that separate it from adjacent watersheds

Answer 20

watershed

Question 21

how water is returned to the atmosphere

Answer 21

Evaporation

Question 22

after plant use it is vaporized from the stomata on the surfaces of the plant leaves

Answer 22

transporation

Question 23

precipitation is intercepted by plant foliage and returned to the atmosphere by evaporation without ever touching soil

Answer 23

interception`

Question 24

the physical condition of the soil in relation to plant grown

Answer 24

tilth

Question 25

Name three primary properties used to delineate soil horizons

Answer 25

color, texture, structure

Question 26

soil solids approximate this percentage of a loam at field capacity

Answer 26

50%

Question 27

ions freely available for absorption by plant roots are found in this fraction

Answer 27

soil solution fraction

Question 28

essential to plant respiration at interface of pedosphere and atmosphere

Answer 28

O2

Question 29

degradation of OM from plant residues is considered this type of soil profile developmental process

Answer 29

transformation

Question 30

limestone PM weathers into this bivalent cation which is an example of what kind of weathering

Answer 30

chemical Ca2+

Question 31

name the five soil forming factors

Answer 31

time, biota, parent material, topography, climate

Question 32

soils with equal amounts of each texture would be in which textural class

Answer 32

clay loam

Question 33

most weathered soil order

Answer 33

oxisol

Question 34

example of a clay mineral with extensive isomorphous substitution

Answer 34

smectite

Question 35

a 1:1 silicate clay mineral

Answer 35

kaolinite

Question 36

pH dependent charge, edge charges

Answer 36

kaolinite

Question 37

vertisols are dominated by what types of charges

Answer 37

permanent charge

Question 38

oxisols are dominated by what type of charge

Answer 38

pH dependent charge

Question 39

clay with largest surface area

Answer 39

smectite, 2:1 w/ interlayer

Question 40

what makes the water stay up in the fine textured stuff

Answer 40

matric potential (surface)

Question 41

how does water move?

Answer 41

wet to dry, high to low potential, and macropores to micropores

Question 42

highest capillary rise ultimately?

Answer 42

clay

Question 43

smallest radius means

Answer 43

greatest height

Question 44

how do you interpret the trends in ksat data with soil depth

Answer 44

it decreases with depth because there is higher clay that slows water movement because it's mostly micropores that just hold the water

Question 45

range in soil water potential that defines the water available to plant roots

Answer 45

wilting point and field capacity

Question 46

soil structure most prevalent in a C horizon

Answer 46

massive

Question 47

soil structure most prevalent in a B horizon

Answer 47

blocky

Question 48

soil structure most prevalent in a E horizon

Answer 48

platy

Question 49

this soil separate is .05 to .002 and not gritty

Answer 49

silt

Question 50

way to increase soil temperature

Answer 50

plastic and organic mulches

Question 51

three factors responsible for soil aeration

Answer 51

soil macroporosity, soil water content, O2 consumption

Question 52

when temperature rises, what happens to microbial activity?

Answer 52

doubles for ever 10 degree increase

Question 53

next terminal electron acceptor when there is no longer any O2

Answer 53

NO3

Question 54

Name the four soil forming processes

Answer 54

additions, losses, transformations, translocations

Question 55

translocation

Answer 55

Movement of soil constituents (organic or mineral) within the profile and/or between horizons.

Question 56

transformations

Answer 56

The chemical weathering of sand and formation of clay minerals, transformation of coarse OM into decay resistant organic compounds (humus)

Question 57

losses

Answer 57

Through the movement of wind or water, or uptake by plants, soil particles (sand, silt, clay, and OM) or chemical compounds can be eroded, leached, or harvested from the soil, altering the chemical and physical makeup of the soil.

Question 58

additions

Answer 58

Materials added to the soil, such as decomposing vegetation and organisms (organic matter--OM), or new mineral materials deposited by wind or water.

Question 59

what is the charge of O?

Answer 59

-2

Question 60

what is the charge of H?

Answer 60

+1