Title: Lecture
1Lecture 6 Plant Nutrition and Soils
Image a soil profile
2Key Concepts
- Resources
- Which are required
- How they are used
- Essential elements
- What they are
- What they do
- Soils and soil forming factors
- The rhizosphere
- Some alternate methods to acquire nutrients
3Resource requirements for plant growth???
?
4Where do plants get these resources???
?
5Where do plants get these resources???
6Image root system of a grass
Diagram plant resource requirements and sources
7Plant tissue composition by weight
- Fresh herbaceous tissue is 80-85 water
- Little water is incorporated into plant tissue
- What does water contribute to tissue???
- Most water is in the cell solution, in the
vacuoles, or passing through in the transpiration
stream
8Critical Thinking
- Does wood have such a high percentage of water???
9Critical Thinking
- Does wood have such a high percentage of water???
10Plant tissue composition by weight
- Fresh herbaceous tissue is 80-85 water
- Little water is incorporated into plant tissue
- What does water contribute to tissue???
- Most water is in the cell solution, in the
vacuoles, or passing through in the transpiration
stream
11Plant tissue composition by weight
- Fresh herbaceous tissue is 80-85 water
- Little water is incorporated into plant tissue
- Water supplies all the H to carbohydrates
electrons and protons for photosynthesis - Most water is in the cell solution, in the
vacuoles, or passing through in the transpiration
stream
12Plant tissue composition by weight
- Fresh herbaceous tissue is 80-85 water
- Little water is incorporated into plant tissue
- Water contributes H to carbohydrates electrons
and protons for photosynthesis - Most water is in the cell solution, in the
vacuoles, or passing through in the transpiration
stream
13DRY plant tissue composition by weight
- 45 carbon
- 45 oxygen
- 6 hydrogen
- 5 inorganic mineral nutrients
14DRY plant tissue composition by weight
- 45 carbon from ?? CO2
- 45 oxygen from ?? CO2
- 6 hydrogen from ?? water
- 5 inorganic mineral nutrients from ?? soil
15DRY plant tissue composition by weight
- 45 carbon from
- 45 oxygen from
- 6 hydrogen from
- 5 inorganic mineral nutrients from
16DRY plant tissue composition by weight
- 45 carbon from
- 45 oxygen from
- 6 hydrogen from
- 5 inorganic mineral nutrients from
17C, H, O source and fate in photosynthesis
Diagram what goes into photosynthesis and what
comes out
18DRY plant tissue composition by weight
- 45 carbon from CO2
- 45 oxygen from CO2
- 6 hydrogen from water
- 5 inorganic mineral nutrients from
- 0.75-1 of wet weight, but many are essential to
plant growth and function
19Critical Thinking
- What is the difference between a chemical
element, a molecule and a macromolecule???
20Critical Thinking
- What is the difference between a chemical
element, a molecule and a macromolecule???
Diagram structure of chlorophyll molecule
21Essential Elements
- Chemical elements
- Not molecules, though some are delivered in that
form N vs. NO3- - Required for growth and function of the plant
- Cant be replaced by some other element
- Some contribute to structural components
- Some contribute to metabolic processes or the
maintenance of homeostasis
22Essential elements in structural plant components
- What are some essential structural components???
?
23Essential elements in structural plant components
24Essential elements in structural plant components
25Essential elements for metabolic processes
- What are some essential molecules used in
metabolic processes???
?
26Essential elements for metabolic processes
27Essential elements for metabolic processes
28Macro Nutrients vs. Micro Nutrients
mass
- Nitrogen
- Potassium
- Calcium
- Magnesium
- Phosphorous
- Sulfur
- Chlorine, Iron, Boron, Manganese, Zinc, Copper
and Molybdenum - Some plants also require Nickel, Sodium, Silicon,
Selenium or others
All used in large quantities to support the
structures and processes listed before
Mostly used in enzymes, as enzyme cofactors or in
electron transfers often reused, less required
29Study table in book!
Table essential nutrients, both macro and micro
30Memory device in honor of my friend and mentor,
Dr. Chuck Davey celebrated in 2006 for 50 years
of service to soil science!!!
- C HOPKNS CaFe, Mg, Mn B CuZn Mo, Cl
- C. Hopkin's cafe, mighty good, managed by cousin
Mo, waitress Clara - Nickel may also be essential
31Some minerals required, some by chance
Images various plants that use additional
elements
Sulfur in mustards
Silicon in horsetails
Uranium in macadamia nuts
32Critical Thinking
- How do you tell which are required???
33Critical Thinking
- How do you tell which are required???
34Critical Thinking
- How do you tell which are required???
- How would elements NOT required enter the plant
tissue???
35Critical Thinking
- How do you tell which are required???
- How would elements NOT required enter the plant
tissue???
36All plants will exhibit signs of deficiencies..
Images signs of deficiency
37Critical Thinking
- If the deficiency appears first in the older
leaves, is that nutrient mobile or immobile???
38Critical Thinking
- If the deficiency appears first in the older
leaves, is that nutrient mobile or immobile??? - How???
39Critical Thinking
- If the deficiency appears first in the older
leaves, is that nutrient mobile or immobile??? - How???
40Fe deficiency in younger leaves ()
Mg deficiency in older leaves ()
41Critical Thinking
- Why would some elements be mobile, and others
not???
42Critical Thinking
- Why would some elements be mobile, and others
not???
43Most plants get most of their nutrients from the
soil absorbed through the roots
Image roots
44Soil is not just Dirt!
- Soil is the skin of the earth
- Soil provides for virtually all our food
- Soil supports the forests that maintain the
hydrological cycle - Soil supports virtually all terrestrial
ecosystems from micro-organisms to charismatic
macro-fauna
45The results of deforestation are ecological,
economic and social disaster ( )
Image erosion after tropical deforestation
46Removing the plants removes the soils protective
blanket and erosion is almost inevitable
47Erosion from deforestation in Madagascar
More images erosion
48Sedimentation from erosion this represents a
huge loss of soil capital
Image sediments from eroded land flooding out
to sea
49Sediments eroding off Haiti
Image sediments eroding off Haiti into the sea
50Dominican Republic
Image the political boundary is clear from the
deforestation
Haiti
51Haitis drought is caused largely by
deforestation the hydrological cycle has been
snapped
Image the drought in Haiti, where residents eat
mud to survive
52Deforestation in Warwickshire, England
Maps deforestation in England and in the US
Deforestation in the US
53Map soil loss in the Southern Piedmont of the
US due to deforestation and abusive agricultural
practices
Piedmont soil erosion in the southeastern US
54Image eroded land in the Southern Piedmont
The USFS Calhoun Experimental Forest in the
1950s Union County, South Carolina
55Loss of soil (along with the boll weevil) nearly
eliminated productive agriculture in the Southern
Piedmont after the 1920s now most of the
Piedmont is in industrial pine plantations
because it can no longer support productive
agriculture
Maps loss of farms, rise of industrial
forestry, creating the biological deserts of pine
plantations
56Social Justice You can help!!!
57Compassionate Thinking
- What can you do to help???
58Compassionate Thinking
- What can you do to help???
59SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
60SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
61SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
62SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
63SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
64SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
65SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
66SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
67SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
68SoilA dynamic natural body in which plants
grow, composed of mineral and organic materials,
air, water, and living organisms
69Soil Forming FactorsParent MaterialClimateLiv
ing OrganismsTopographyTime
All soil forming factors interact!!!
70Parent Material
- The substrate from which soil forms
- May be bedrock or some deposited material
(sediments, organic material) - Determines soil texture, mineral content
- Influences soil structure and pH
71Igneous rocks form from molten rock
72Pegmatite granite with large-grained feldspar
(slow cooling)
73Sedimentary rocks form from deposited materials
74Flat sedimentary rocks
Sedimentary rocks after tectonic thrusting and
folding
75Metamorphic rocks form from igneous or
sedimentary rocks that have been altered by heat
and pressure
76gneiss
77In the Charleston area, our soils form from
unconsolidated Coastal Plain sediments
78Critical Thinking
79Critical Thinking
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82PM determines soil texture percentage of sand,
silt and clay Loam soils have equal
percentage of each texture class
83CLAY
84Clays are especially important
- Tiny (lt2um)
- Huge surface area per unit mass (1000X more than
same volume of sand) - Typically platy in structure vast additional
internal surface area (800 m2/gm) - Typically clay minerals carry a negative charge
85Critical Thinking
- Why is a huge surface area of negative charge
important to soil fertility???
86Critical Thinking
- Why is a huge surface area of negative charge
important to soil fertility???
87Most clays carry negative charge on both external
and internal surfaces
88Cation Exchange remember the root cap protons
displace cations
89Texture also influences soil moisture clays
hold onto more water Small pore size and
negative charge Relationship between soil
texture, field capacity and water availability
90Parent materials are weathered by other soil
forming factors to form soil
91Soils are typically layered, in horizons, because
of downward movement of water, clays, etc
92Critical Thinking
- Which soil horizon has the most biological
activity??? - Why???
93Critical Thinking
- Which soil horizon has the most biological
activity??? - Why???
94A Horizon The topsoil is the most biologically
active horizon more air, water and organic
materials from the surface
95Soil Profile a cut that reveals the horizons
96Climate
- Primarily temperature and precipitation patterns
- Temperature controls freeze-thaw cycles that
contribute to physical weathering - Temperature also affects the rate of biochemical
reactions - Temperature also affects the rate of
decomposition by fungi, bacteria, and other
living organisms
97Climate
- Precipitation contributes to soil moisture, which
affects plant growth and the activity of
decomposing organisms - Precipitation affects erosion (the physical loss
of soil particles) and leaching (chemical losses
from the soil solution as water passes through
the soil this contributes to profile formation)
98Major biomes are determined by climate
microclimate is also important in soil development
99Living Organisms
- Macro-organisms, including plants and animals
- Micro-organisms, including bacteria, fungi,
single-celled protists, and micro-fauna - Human activity typically results in abrupt and
very negative changes to soil
100Living Organisms Plants
- Contribute organic material both from above
(shoots) and below (roots), and both sources
affect horizonation - Help to mix the soil root channels, wind throws
- Cycle nutrients from soil to plant and back
(sometimes through animals, always through
decomposers) - Help prevent soil erosion by breaking the force
of rain, providing a litter layer
101Same parent material will develop into a
different soil under different plant communities
102Critical Thinking
- Why are grassland soils so dark at the surface???
103Critical Thinking
- Why are grassland soils so dark at the surface???
104Living Organisms Animals
- Help to mix the soil by burrowing, some even
eat soil (earthworms)
- Contribute organic material when they die
- Contribute to nutrient cycling
105Critical Thinking
- How do animals contribute to nutrient cycling???
106Critical Thinking
- How do animals contribute to nutrient cycling???
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108Living Organisms Micro-orgs
- Decompose organic material, cycle nutrients, add
OM - Trillions/kg of soil (double handful of soil.)
- N-fixing bacteria supply virtually all N for
plant growth, either free living or in nodule - the nitrogen paradox.bacteria convert
atmospheric N to forms suitable for plant uptake - Mycorrhizae mutual symbiotic association
between fungi and roots, present in most plants,
required by some
109Small animals, soil dwelling micro-fauna, fungi,
bacteria, and other micro-organisms decompose
dead OM, cycling nutrients back into the soil
110Living Organisms Micro-orgs
- Decompose organic material, cycle nutrients, add
OM - Trillions/kg of soil (double handful of soil.)
- N-fixing bacteria supply virtually all N for
plant growth, either free living or in nodule - The nitrogen paradox.bacteria convert
atmospheric N to forms suitable for plant uptake - Mycorrhizae mutual symbiotic association
between fungi and roots, present in most plants,
required by some
111N-fixing bacteria in symbiotic mutualisms, mostly
with legumes
112Living Organisms Micro-orgs
- Decompose organic material, cycle nutrients, add
OM - Trillions/kg of soil (double handful of soil.)
- N-fixing bacteria supply virtually all N for
plant growth, either free living or in nodule - the nitrogen paradox.bacteria convert
atmospheric N to forms suitable for plant uptake - Mycorrhizae mutual symbiotic association
between fungi and roots, present in most plants,
required by some
113Critical Thinking
- What do you think mycorrhizae might contribute to
the symbiosis???
114Critical Thinking
- What do you think mycorrhizae might contribute to
the symbiosis???
115Mycorrhizae are symbiotic mutualisms between
fungi and plants fungal hyphae vastly increase
surface area for water and nutrient absorption
85 of plants depend on them
116Living Organisms The human impact
- Removing vegetation dramatically increases
erosion, cultivation exacerbates - Deforestation can snap hydrological cycles
- Excessive fertilizer and pesticide use
contaminates both soil and water - Improper irrigation salinates soil
- Wetland drainage damages wetland soils
- and on.
117Topography the shape of the land
- Determines the movement of water, thus affecting
erosion and leaching rates - Determines where water accumulates, which affects
soil moisture, which affects organismal activity,
which affects soils. - Aspect affects the amount of solar radiation at
the surface, and thus soil temperature - Large topographic features influence
precipitation patterns - Even micro-topography influences plant
distribution
118Topographic Aspect red and blue face S and W
green and yellow face N and E
119Critical Thinking
- Why are the north and east slopes of a hill
cooler???
120Critical Thinking
- Why are the north and east slopes of a hill
cooler???
121Topography the shape of the land
- Determines the movement of water, thus affecting
erosion and leaching rates - Determines where water accumulates, which affects
soil moisture, which affects organismal activity,
which affects soils. - Aspect affects the amount of solar radiation at
the surface, and thus soil temperature - Large topographic features influence
precipitation patterns - Even micro-topography influences plant
distribution
122Orographic lifting makes it rain
123Critical Thinking
- What the heck is orographic lifting and why does
it cause rain???
124Critical Thinking
- What the heck is orographic lifting and why does
it cause rain???
125Critical Thinking
- What the heck is orographic lifting and why does
it cause rain???
126Orographic lifting causes cooling and
precipitation, rain shadow to the leeward
127Topography the shape of the land
- Determines the movement of water, thus affecting
erosion and leaching rates - Determines where water accumulates, which affects
soil moisture, which affects organismal activity,
which affects soils. - Aspect affects the amount of solar radiation at
the surface, and thus soil temperature - Large topographic features influence
precipitation patterns - Even micro-topography influences plant
distribution
128Small change in elevation
big change in the plant community!
129Time.
- The length of time all these factors have been
acting determines the characteristics of the soil - The same parent material will develop different
soils as time passes - Major component of primary succession
130Soil development on glacial till
131Soil Forming FactorsParent MaterialClimateLiv
ing OrganismsTopographyTime
Remember all soil forming factors interact!!!
132The Rhizosphere
The area of interaction between root and soil. A
huge volume of soil, but a very narrow zone
133The rhizosphere is the zone of cation exchange,
nutrient and water uptake
134The Rhizosphere
- Complex zone with many interacting factors
- Plant affects soil through compounds secreted by
the plants roots - Relative proportions of nutrients in the soil
solution can affect uptake of all nutrients - Also, different species have different nutrient
requirements - Rhizosphere is the control zone for plant/soil
interactions
135Some plants use alternate methods to absorb some
nutrients
- Parasites, saprophytes, carnivores
136Key Concepts QUESTIONS???
- Resources
- Which are required
- How they are used
- Essential elements
- What they are
- What they do
- Soils and soil forming factors
- The rhizosphere
- Some alternate methods to acquire nutrients