Turf Management > Test 2_Soils > Flashcards

Test 2_Soils Flashcards

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1
Q

turfgrass soils definition:

A

a complex medium of inorganic and organic materials. the soil also ontains various gases and water.

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2
Q

Soil horizons (list)

A

O-horizon

A-horizon

B-horizon

C-horizon

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3
Q

O-horizon

A

layer of undecomposed and partially decomposed organic matter = THATCH AND MAT

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4
Q

A-horizon

A

topsoil composed of mineral particles and organic matter giving it a dark rich color

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5
Q

B-horizon

A

subsoil, low in organic matter and high in clay

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6
Q

C-horizon

A

zone of partially weathered parent material often over solid bedrock

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7
Q

soil texture refers to:

A

the proportion of sand, silt and clay particles

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8
Q

soil texture determines:

A

many chemical and physical properties of the soil

  • How compaction prone is it?
  • How well will it hold moisture? etc
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9
Q

sand characteristics

A
  • large particles
  • low CEC
  • Compaction resistant
  • low water holder

high infiltration

  • high aeration porosity
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10
Q

clay characeristics

A
  • tiny particles
  • medium CEC
  • compacts
  • high water holder
  • low infiltration
  • low aeration porosity
  • poor aggregation
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11
Q

to improve both sand and clay soils:

A

add organic matter

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12
Q

soil structure refers to:

A

the arrangement of mineral particles

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13
Q

anything that fractures or separates soil particles may promore aggregation. for example:

A
  • root penetration
  • freezing and thawing
  • wetting and drying
  • earthworm activity
  • ripping and tilling
  • core aeration
  • solid tining, knifing, etc
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14
Q

______ may improve the potential for aggregation

A

calcium

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15
Q

clay particles have a _____ charge on their surface

A

negative

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16
Q

density =

A

mass per unit volume

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17
Q

particle density =

A

density of soil solids; on average it is 2.65 g/cc

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18
Q

bulk density:

A

dry weight of undisturbed soil partiles / unit volume…

desirable bulk densities vary depending upon the soil texture

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19
Q

bulk density details

A
  • dry weight of a specific volume of soil
  • includes both solids and pores
  • expressed as grams/cc
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20
Q

it is important to compare soils of _____ ______ when trying to compare bulk densities

A

bulk densities

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21
Q

a well structured soil will have a sufficient amount of both _______ and ______ space

A

macropore and micropore

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22
Q

macropores:

A

comparatively large proes that are important for water drainage and soil aeration

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23
Q

micropore:

A

very small pores that are important in holding water for plant use

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24
Q

infiltration =

A

water moving into the soil

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25
percolation =
water moving through the soil profile
26
adhesion =
attraction of water to soil particles
27
cohesion =
attraction of water molecules to other water molecules
28
imporatince of soil aeration
- root growth - gas exchange - microbial activity is supported by adequate aeration
29
as soil temperature increases....
the rates of reactions increase
30
thermal heatins is a result of:
- soil color - soil moisture - soil organic matter
31
specific heat is highest for \_\_\_\_
WATER \> ORGANIC MATTER \> DRY MINERAL SOIL
32
soil colloids are
- clay and organic material "humus"
33
primary soil colloids of clay
Al, Si, O arranged as "planes" of atoms that share charges
34
isomorphic substitution:
other cations can be substituted for Al, Si, and O in clays
35
charges associated with process of isomorphic substitution
permanent charges
36
essentially, increases the CEC of a soil
ispmorphic substitution
37
pH dependent charge
as the soil becomes more acid, open sites become filled with H+
38
charge primarily associated with soil organic matter
pH dependent charge
39
actively growing grass is \_\_\_\_-\_\_\_\_% water
75-85%
40
Macronutrients
N, P, K, Ca, Mg, S
41
micronutrients
Fe, Mn, B, Mo, Cu, Zn, Cl, Ni
42
most prominent cations in a soil
Ca 2+ Mg 2+ NH 4+ Na + H+
43
prominent cations can be\_\_\_\_\_ dependent on their concentrations in the soil
exchanged
44
CEC is:
not a measure of soil fertility, but of "potential" to hold cations
45
CEC =
cation exchange capacity
46
the higher the CEC of a soil...
the more buffered the soil is to change
47
high clay content soils are \_\_\_\_ly buffered
highly
48
high sand content soils are \_\_\_ly buffered
poorly
49
buffering capacity =
a soil's resistance to chemical changes
50
water moves into roots by \_\_\_\_
osmosis
51
major factor influencing pH is
precipitation
52
\_\_ and __ are minerals that neutralize acidity and raise pH
Ca and Mg
53
high rainfall, irrigation, roots exuding acid forming substance, and nirtogen fertilizers result in=
lowering pH and a need for liming
54
lime is:
an amendment used to raise soil pH
55
lime is (chem)
Calcium Carbonate CaCO3
56
dolomitic lime (chem)
Mg(CaCo3)
57
adding too much lime will:
- saturate CEC sites with Ca 2+ and raise pH above 8, restricting N, P, K, and Fe availability
58
large lime applications should be:
split into spring and summer applications following core aeration
59
\_\_ can be used to lower pH on alkaline soils that are not highly calcareous
sulfur
60
deflocculation =
loss of soil structure or aggregation, leading to loss of soil permeability because large pores are virtually destroyed by hydrated Na+
61
primarily used to teal with sodic (Na) soil problems
gypsum
62
gypsum chem formula
CaSO4
63
activities of bacteria in the soil
- organic matter decomposition - nutrient transformation
64
saprophytes feed on:
decaying plant material
65
parasites feed on:
living plant material
66
faculative fungi prefer:
to feed on one type of plant material, but will attack and feed on the other if quantities are limited
67
obligate fungi are:
organizms that exclusively feed on eiher living or dead plant material
68
many turf pathogens are:
faccultative parasites
69
simple plants that lack chlorophyll
fungi
70
single-celled plants that can remain independent or can be associated together in long chains
algae
71
formerly known as blue-green algae
cyanobacteria
72
cyanobacteria (problems)
- major problem in warmer months - causes yellowing in turf - more common in higher pH soils
73
an average soil will contain \_\_-\_\_% organic matter
1-3%
74
organic matter:
- improves soil structure - improves aeration - improves water holding capacity - improves CEC (ph dependent charge) - improves release of nutrients as a result of decomposition
75
thatch
layer of living and non-living plant material located immediately above soil surface - 1/2" or less is usually deemed desirable in turf
76
complete modification =
bring in a topsoil to serve as the 8 - 12 inch rootzone
77
\_\_ and __ are preferred topsoils on general turf areas
loams and sandy loams
78
\_\_\_ soils are preferred for greens and high-traffic ball fields
sand
79
partial modification =
incorporating materials into existing soil to improve structure and texture
80
don't incorporate sand into clay unless:
you can change 6-8 inch deep texture to 70% or more of sand
81
\_\_ may be called the "stress-building" nutrient
potassium
82
\_\_ regulates stomatal opening/closing for better drought avoidance/cold disiccation tolerance and helps build/maintain strong cell walls for better wear tolerance
potassium
83
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