Exam 2

Front 1

Floating free in bulk water that is moving laterally and eventually dumped into a surface stream--where in the soil system are they?

Back 1

Ground water

Front 2

__________ happens because soil pores are tortuous, irregular, or discontinuous

Back 2

Hysteresis

Front 3

If you dig a hole in your back yard and water seeps into the hole, it will fill the hole up to _______ with water.

Back 3

The water table / phreatic surface

Front 4

T/F Evapotranspiration includes water vapor losses both from the soil surface and from the leaves of plants.

Back 4

True

Front 5

T/F The gravitational potential of water in the soil is usually negative.

Back 5

False

Front 6

Soils high in OM commonly hold more available water than comparable soils with lower OM levels most likely due to __________

Back 6

Better soil aggregation

Front 7

At whihh kPa of total soil moisture is the soil water held most tightly?

Back 7

-3100

Front 8

Plant roots obtain better access to soil water when ______

Back 8

Roots grow and extend into moist soil areas

Front 9

T/F The water potential at the field capacity for most soils is in the range of -10 to -30 kPa.

Back 9

True

Front 10

T/F Osmotic and matrix potentials are negative.

Back 10

True

Front 11

T/F The osmotic potential is created by the presence of salts and other solutes in the soil.

Back 11

True

Front 12

T/F The matrix potential is due to the attraction of water molecules to the surfaces of soil particles.

Back 12

True

Front 13

When water leaves the saturated ground water zone and enters a surface stream or lake, the best word to describe the process is ________.

Back 13

Discharge

Front 14

T/F Acid functional groups on humus may provide negative charges.

Back 14

True

Front 15

____________ clays may be negatively charged because of isomorphous substitution.

Back 15

Aluminosilicate

Front 16

T/F A 2:1 layer lattice (aluminosilicate) clay has 2 tetrahedral sheets and 1 octahedral sheet.

Back 16

True

Front 17

The pool of acidity called "_________ acidity" determines the lime requirement of the soil.

Back 17

Residual

Front 18

A soil with a ______ percent base saturation will be more likely to have a relatively high pH.

Back 18

Higher

Front 19

________ in the soil make the soil more workable by stabilizing the structural units called aggregates.

Back 19

Colloids

Front 20

Which aluminosilicate clay experiences the least amount of swelling and shrinking?

Back 20

Kaolinite

Front 21

T/F Montmorillonite is the most common of the swelling/shrinking smectites, which are 2:1 aluminosilicate clays.

Back 21

True

Front 22

In isomorphous substitution it is common for __ to replace __.

Back 22

Mg to replace Al

Front 23

T/F The reason that an aluminosilicate clay is non-swelling/shrinking may be because the layers are held together by hydrogen bonds or by K+ in hexagonal holes in the domains of the layers.

Back 23

True

Front 24

If the pH of a solution is 4.5, the pOH of that solution will be ___.

Back 24

9.5

Front 25

_________ is often used as a China clay.

Back 25

Kaolinite

Front 26

Because aluminum can act as either an acid or a base, it is called _________.

Back 26

Amphoteric

Front 27

____ is an important soil property to know because it helps determine the availablity of several essential elements.

Back 27

pH

Front 28

T/F Buffering is a resistance to change.

Back 28

True

Front 29

T/F Humus in the soil may be hundreds of years old.

Back 29

True

Front 30

T/F An acquired soil characteristic (property) is always inherited from the parent material.

Back 30

False

Front 31

T/F As a non-polar molecule, water can easily infiltrate small pores in the soil.

Back 31

False

Front 32

T/F The standard, professionally accepted expression of the water content of the soil uses the calculation: %H2Om=100x (mass water in soil/mass of wet soil)

Back 32

False

Front 33

T/F There is no mathematical relationship between the mass water content of a soil and the volumetric water content of the same soil at the sand moisture content.

Back 33

False

Front 34

Water has a specific heat of ___ calorie per gram per degree Celcius.

Back 34

1

Front 35

The standard soil water content determination by gravimetric analysis _________.

Back 35

Heats the sample in an oven

Front 36

T/F Standard measurement of soil water content expresses the value as kilograms of water per kilogram of dry soil.

Back 36

True