Soil moisture and groundwater recharge

Question 1

The uppermost layer of the earth may contain a three-phase system of ____, ____, and _____ material

Answer 1

solid, liquid, and gaseous

Question 2

the layer that contains the three-phase system is called the

Answer 2

zone of aeration, unsaturated zone or the vadose zone

Question 3

the solid phase of vadose zone may consist of:

Answer 3

soil formed by in-situ weathering

sediments weathered and transported

unweathered bedrock

Question 4

smaller grains may also be bounded by organic matter to form larger units called

Answer 4

aggregates or peds

Question 5

the soil texture is determined by the:

Answer 5

distribution of the size fractions of mineral grains present

Question 6

scientists break soils down into how many textural classes

Answer 6

12

Question 7

scientists classify soils based on the percentages of ____, _____, and ____ paticles

Answer 7

clay, silt, and sand-sized particles

Question 8

helps determine the drainage and fertility characteristics of a soil

Answer 8

soil texture

Question 9

size ranges for sand, silt, and clay for soil scientists

Answer 9

clay - <0.002mm
silt - 0.002 - 0.05 mm
sand - 0.05 to 2 mm

Question 10

is the mass of the soil water content divided by the mass of the solid particles (dry mass of the soil)

Answer 10

gravimetric water content

Question 11

formula for gravimetric water content

Answer 11

gwc = Ww / Ws

mass of water in the soil / dry mass of the soil

Question 12

the volume of the soil water divided by the volume of the soil

Answer 12

volumetric water content

Question 13

formula for volumetric water content

Answer 13

vwc = Vw / V

volume of soil water divided by volume of the soil

Question 14

formula for saturation ratio

Answer 14

Rs = Vw / Vv

volume of soil water divided by the volume of the voids of the soil

Question 15

formula for dry bulk density

Answer 15

Pb = Ws / V

dry mass of the soil divided by the volume of the soil

Question 16

formula for particle density

Answer 16

Pd = Ws / Vs

mass of the mineral particles divided by the volume of soil particles

Question 17

soil moisture can be measured indirectly by

Answer 17

non-destructible means

Question 18

one method of measuring soil moisture involves burying of ____ called _____, in which _____ are embedded and electric currents are passed through wires

Answer 18

small blocks
resistance cells
electrodes

Question 19

small blocks that are buried in which electrodes are embedded to

Answer 19

resistance cells

Question 20

is the depression or the rise of a liquid in a small capillary passage tube

Answer 20

capillarity

Question 21

t or f: openings in the porous materials exhibit capillarity

Answer 21

T

Question 22

this is the subsurface layer in which groundwater seeps up from a water table by capillary action to fill pores

Answer 22

capillary fringe

Question 23

groundwater seeps up from a water table through

Answer 23

capillary action

Question 24

pores at the base of the capillary fringe are filled with water because of

Answer 24

tension saturation

Question 25

capillarity results from 2 force, what are these forces?

Answer 25

mutual attraction among water molecules (cohesion) attraction of water molecules into different soil materials (adhesion)

Question 26

t or f: because of capillarity, water level will rise in a small glass tube above the water level in a large container

Answer 26

T

Question 27

the smaller the tube diameter, the _____ the rise of the water column

Answer 27

greater

Question 28

the capillary fringe can provide a means for direct evaporation if

Answer 28

the water table is close enough to the ground surface

Question 29

measuring instrument used to determine water potential (soil moisture tension) in the vadose zone

Answer 29

tensiometer

Question 30

device that typically consist of glass or plastic tube with a porous ceramic cup filled with water

Answer 30

tensiometer

Question 31

a tensiometer is a device used to determine _____ or _______ in the ______. it consist of a ____ or _____ and a _______ filled with water

Answer 31

water potential soil-moisture tension vadose zone glass or plastic tube ceramic porous cup

Question 32

water in the vadose zone available to growing of plants, found in the belt of soil water

Answer 32

soil water

Question 33

soil water zone extend from

Answer 33

the land surface to the depth of roots of the plants

Question 34

top of the capillary fringe may be below the

Answer 34

belt of soil water

Question 35

soil moisture at a location varies with changes in the

Answer 35

amount of precipitation and evapotranspiration

Question 36

also known as soil evapotranspiration

Answer 36

soil water evaporation

Question 37

when the soil moisture content of a layer reaches to a point where the gravity attraction is equal to the surface tension, gravity drainage ceases.

Answer 37

Field capacity

Question 38

field capacity happens when gravity equals the surface the tension, therefore _____

Answer 38

gravity drainage ceases

Question 39

field capacity depends on the

Answer 39

specific retention evaporation depth unsaturated permeability characteristic curve of the soil

Question 40

happens when the remaining moisture is too tightly bound to the soil particles

Answer 40

wilting point

Question 41

field capacity is ______ proportional to grain size

Answer 41

inversely

Question 42

soil texture with highest field capacity

Answer 42

clay

Question 43

soil texture with lowest field capacity

Answer 43

sand

Question 44

t or f: field capacity of a soil texture is directly proportional to its wilting point

Answer 44

T

Question 45

10 soil textures arranged from lowest field capacity to highest

Answer 45

sand fine sand sandy loam fine sandy loam loam silt loam light clay loam clay loam heavy clay loam clay

Question 46

capillary fringe rises as groundwater is being ____

Answer 46

recharged

Question 47

time of movement of infiltrating water is a function of

Answer 47

thickness of the unsaturated zone and the vertical unsaturated hydraulic conductivity

Question 48

soil texture is important because it determines the

Answer 48

drainage and fertility characteristics of the soil

Question 49

mixture of silt, David, and clay

Answer 49

loam

Question 50

soil in usep obrero are mostly

Answer 50

clay and clay loam

Question 51

soils are characterized by

Answer 51

sorting, size, and mineral grains present

Question 52

weathered rock material containing organic compounds

Answer 52

soil

Question 53

unconsolidated rock materials

Answer 53

regolith

Question 54

what are peds

Answer 54

aggregate of soils

Question 55

the ratio of the volume of the void to the volume of the solids

Answer 55

void ratio

Question 56

common properties used to analyze/determine moisture content

Answer 56

porosity void ratio gravimetric water content volumetric water content saturation ration dry bulk density particle density

Question 57

t or f: capillarity aids in evapotranspiration

Answer 57

T

Question 58

a body of the tensiometer constructed of tough Butyrate plastic

Answer 58

irrometer body

Question 59

irrometer body is constructed of

Answer 59

tough butyrate plastic

Question 60

t or f: ceramic porous tip allows adhesion of water molecules

Answer 60

T

Question 61

t or f: water table rise when groundwater is being recharged

Answer 61

T

Question 62

annual precipitation in arid regions

Answer 62

<300 mm

Question 63

annual precipitation in davao

Answer 63

1000-1,5000 mm

Question 64

annual precipitation in surigao

Answer 64

>2000 mm annually

Question 65

high evapotranspiration causes water table to

Answer 65

lower

Question 66

recharge and level of water table is dependent on the

Answer 66

thickness of unsaturated zone precipitation rate of discharge hydraulic conductivity topographic condition geology