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Flashcards in SOIL Deck (85):
1

Define soil

a loose mixture of small rock fragments, organic matter, water and air that can support the growth of vegetation.

2

1st step of soil formation is

weathering of a parent rock

3

in soil formation, the parent rock is the source of

inorganic particles

4

soil forms where

directly above the parent rock

5

what breaks down the parent rock?

weathering

6

parent rock is broken into smaller pieces and mixes with what

organic matter

7

what two things form soil?

small pieces of parent rock + organic matter

8

what are two decomposers that live in soil

bacteria and fungi

9

the decomposers break down the remains of

plants and animals

10

the remains of decayed organic matter is called

humus

11

humus is found where

the top layers of soil

12

humus contains

the nutrients that plants need to grow

13

larger animals such as earthworms and moles do what to the soil

loosen and mix

14

when animal loosen and mix soil, what results

increases the air in soil and improves soil ability to drain water

15

what are the 4 main factors determine how long it takes for soil to form

rock type, climate, topography, plants/animals

16

rock types weather at different rates and different ways T or F?

true

17

weathering of the rock depends on the

structure and minerals that make up the rock

18

soil usually develops more quickly in what climate

warm and wet

19

soil develops faster in what topography

flatter (not steep slopes)

20

soil in areas with lots of plants and animals develop

FASTER than in areas without plants and animals

21

a vertical section of soil that shows layers is called

soil profile

22

each layer of soil have different physical properties called

soil horizon

23

what is A horizon?

the top of the soil profile

24

what is B horizon?

below horizon A

25

what is C horizon?

below the B horizon

26

in what layers do decomposers live

Horizon A

27

which layer has most decayed matter

Horizon A

28

what color is humus on Horizon A

very dark color

29

what layer is the most developed and rich?

horizon A

30

which layer has the most humus

horizon A

31

in what layer does leaching happen

horizon B

32

what causes horizon B to be reddish in color?

leaching

33

explain leaching

after it rains, water seeps from layer A to layer B and washes away minerals and clay from soil.

34

what layer is least developed

horizon C

35

horizon C lies directly above the what

parent rock

36

does horizon C have organic matter

NO

37

what layer has largest rock fragments

horizon C

38

what are 6 properties of soil

texture, color, chemistry, pore space, fertility, permeability

39

what describes the size of soil particles

texture

40

soil particles are classified

as sand, silt or clay

41

most soils have all three--sand, silt, clay T or F

TRUE

42

what is the largest soil particle

SAND

43

what is sand particle size?

.05mm to 2mm

44

soils with a lot of sand feel

coarse

45

silt particles are what size

0.002mm to .05mm

46

soil with a lot of silt feel

smooth and silky

47

clay particles are how big

less than .002mm

48

soil with a lot of clay feel

smooth and sticks together when wet

49

soil can be what colors

black, brown, red, orange, yellow, gray and white

50

what determines the color of soil

the amount of minerals and organic matter in soil

51

what makes soil orange or reddish

iron

52

what makes soil black or brown

lots of humus

53

color of soil can be a clue about

environmental conditions

54

what does gray soil mean

too wet and poor drainage

55

soils are usually what color

a mixture of alot of colors

56

soil PH is determined by

combination of minerals, sediment and organic matter in soil

57

the soil PH measures how

acidic or basic a soil is

58

soil PH is measured on a scale of what to what

0 - 14

59

if ph is less than 7, soil is

acidic

60

if pH is more than 7 soil is

basic

61

a ph of 7 means

neutral--nor acid or basic

62

the PH level is used to determine

whether or not soil can support different plants

63

soy beans grow best at what PH

6 and 7

64

peanuts thrive at PH of

5.3 and 6.6

65

pore space describes

the space between soil particles

66

what is found between the pore spaces of soil

water and air

67

water and air move more easily through soils with

many well connected pore spaces--good plant growth

68

what percentage of soil is pore space

between 25 and 60 percent

69

the best soil for growing has about ____ pore space

50% (equally divided between water and air)

70

how do you describe soil fertility

how well soil can support plant growth

71

factors than can affect fertility include

climate, humus, minerals, nutrients in soil and topography

72

what are best conditions for fertile soil

moderate rainfall and moderate temperatures

73

high soil fertility has small amounts of humus

FALSE

74

Proper proportions of minerals and nutrients = high soil fertility T or F

TRUE

75

soil in dry areas or steep hillsides have high fertility

FALSE

76

Name three ways farmers can improve soil fertility

1. add chemicals
2. grow certain crops to restore nutrients
3. leave land unplanted for a season

77

define permeability

property of soil which allows water to pass through

78

some of the MAJOR problems of soil is connected to

permeability

79

Too much soil permeability can be

a disaster!

80

Permeability of soil is connected to the success of

the design of highways, airports, earth dams etc...

81

what will happen to plants if there is too much permeability

they will be transported

82

what happens to plants if soil has not enough permeability

plants cannot get the water/nutrients they need

83

If low permeability, it takes longer or shorter for soil to form

LONGER

84

what is porosity

the volume of spaces between soil particles

85

what is the definition of permeability

the ability to transmit or release fluids