Title: Soils and Plant Nutrition Master Gardener Class
1Soils and Plant NutritionMaster Gardener Class
2What is Soil?
Soil is the medium in which plants grow - the
basis for plant growth.
3Four Major Components of Soil
Air
20-30
Mineral
45-48
Water
20-30
Organic Matter
2-5
4Soil Components
Sand 2.0 to 0.05mm Silt 0.05 to
0.002mm Clay less than 0.002mm
Mineral
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6The proportion of sand, silt and clay determine a
soils texture.
7Soil texture determines a soils water-holding
capacity
8Relationship Between Soil Texture and Water
Availability
9Five Things Organic Matter Does for Soil
- Improves the soils physical condition.
- Supplies plant nutrients.
- Increases water infiltration.
- Helps decrease erosion.
- Improves soil tilth (the soils ability to resist
compaction). - Basically natures way of recycling!
10The Ideal Soilfor Crop Production
- Medium texture and organic matter for air and
water movement - Sufficient clay to hold soil moisture reserves
- Deep, permeable subsoil with adequate fertility
levels - Environment for roots to go deep for moisture and
nutrients
11Soil Depth InfluencesRelative Productivity
Soil depth usable Relative by roots,
ft. productivity,
1 35 2 60 3 75 4 85 5 95 6 100
12Soil Slope AffectsRelative Productivity
Relative productivity,
Soil slope, Not easily eroded Easily eroded
0-1 100 95 1-3 90 75 3-5 80 50 5-8 60 30
13The smallest particles of soil are called
colloids. Colloids have a negative charge so
they attract positively charged particles.
Colloids repel other negatively charged particles
- like a magnet.
An element or group of elements with an
electrical charge is called an ion. Ions with
negative charges are called anions. Ions with
positive charges are called cations.
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16Cation Exchange Capacity
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18Plant Nutrients
C HOPKNS CaFe Mg B Mn Cu Zn Mo Cl
See Hopkins Cafe Managed By My Cousin Mo Clay
19Carbon - Hydrogen - Oxygen The three most
abundant elements - plants obtain them from water
and air. These three elements make up more than
94 of plant dry tissue. The remaining 13
elements make up less than 6 of plant dry tissue.
20Macronutrients
Manganese Iron Boron Zinc Copper Molybdenum Chlori
ne
Nitrogen Phosphorus Potassium Sulfur Calcium Magne
sium
Micronutrients
21Roots contact onlya small percentageof
available nutrients
22Nitrogen . . . (N)
- A nitrogen deficiency most limits plant growth.
- Provides a visual green response in plants.
- Plants use large amounts of nitrogen.
- Necessary for the production and transfer of
energy - photosynthesis. - Stimulates plant growth.
- Increases seed and fruit yield.
- Improves the quality of leaf and forage crops.
- Present in the soil in three forms.
23- Nitrogen is present in the soil in three major
forms - Organic
- Inorganic
- Elemental
24The Nitrogen Cycle
Atmospheric nitrogen
Industrial fixation (commercial fertilizers)
Atmospheric fixation and deposition
Crop harvest
Animal manures and biosolids
Volatilization
Plant residues
Runoff and erosion
Biological fixation by legume plants
Plant uptake
Denitrification
Organic nitrogen
Nitrate (NO3)
Ammonium (NH4)
-
Immobilization
Leaching
Mineralization
Component
Input to soil
Loss from soil
25Nitrogen Deficiency
26Phosphorus . . . (P)
- Also an essential part of photosynthesis.
- Responsible for utilization of starch and sugar.
- Cell nucleus formation.
- Cell division and multiplication.
- Cell organization.
- Transfer of heredity.
27Phosphorus Cycle
28Phosphorus Deficiency
29Potassium . . . (K)
- After nitrogen, plants use the largest amount of
potassium. - Plays an essential role in the metabolic process
of plants. - Plays a role in raising the disease resistance of
many plant species.
30How Potassium Moves in Soil
31Potassium Deficiency
32Calcium . . . (Ca)
- An essential part of the wall structure and
strength of plant cells. - Provides for normal transport and retention of
other elements. - Does not move in plant, deficiency develops in
new leaves - Counteracts the effects of alkali salts and
organic acids within the plant.
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34Magnesium . . . (Mg)
- Is essential for photosynthesis.
- Makes up a part of the chlorophyll in green
plants. - Helps activate plant enzymes needed for plant
growth. - Dolomitic lime and epsom salts contain Magnesium
35Magnesium Deficiency
36Sulfur . . . (S)
- Activates plant enzymes.
- Is required for nodulation and nitrogen fixation
of legumes. - Present in glycosides which give the
characteristic odors and flavors of mustard,
onion and garlic.
37Soil organic matter is a majorsource of S
S
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39Manganese . . . (Mn)
- Activates plant enzymes.
- May substitute for magnesium
Iron . . . (Fe)
- Essential for the synthesis of chlorophyll.
- Symptoms include chlorosis between the veins with
green veins
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41Copper . . . (Cu)
- Essential for plant growth.
- Activates many plant enzymes.
Zinc . . . (Zn)
- Regulates plant growth by controlling the
synthesis of indoleacetic acid. - Activates plant enzymes.
42Boron . . . (B)
- Regulates the metabolism of carbohydrates in
plants.
Molybdenum . . . (Mo)
- Required in tiny amounts.
43MicronutrientsARE NOTmiracle workers
44Nutrient Deficiencies
- A note about nutrient deficiencies
- While many deficiencies show specific symptoms
this is an inexact science at best. - Many of the symptoms overlap so the only way to
be sure is with a combination of tissue analysis
and soil sampling.
45Nutrient Deficiency Symptoms
Nutrient Position on plant Chlorosis Leaf margin necrosis? Color and leaf shape
N All leaves Yes No Yellowing of leaves and leaf veins
P Older leaves No No Purplish patches
K Older leaves Yes Yes Yellow patches
Mg Older leaves Yes No Yellow patches
Ca Young leaves Yes No Yellow leaves
S Young leaves Yes No Yellow leaves
Mn, Fe Young leaves Yes No Interveinal chlorosis
B, Zn, Cu, Mo Young leaves - - Deformed leaves
46Soil pH is a measure of the hydrogen ion
concentration in the soil.
Buffer pH is the soils ability to resist changes
in pH.
47pH Units
Optimum pH for most plants 5.5 to 6.5
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49Factors in Addition to Soil pH Which Influence
the Frequency of Liming
- Soil texture
- Rate of N fertilization
- Rate of crop removal of Ca and Mg
- Amount of lime applied
- pH range desired
- Tillage system
- Irrigated crops
50Why Acid Soils Should Be Limed
- Increases CEC in variable charge soils
- Increases availability of several nutrients
- Supplies Ca and Mg to plants
- Improves symbiotic N fixation in legumes
- Improve crop yields
- Reduces Al and other metal toxicities
- Improves the physical condition of the soil
- Stimulates microbial activity in the soil
51Soil Acidity Affects Plant Growth
- Aluminum, Fe and Mn can reach toxic levels
because of increased solubilities in acid soils - Reduced activity of organisms responsible for the
breakdown (mineralization) of organic matter - Possible Ca deficiency . . . but most likely a Mg
deficiency
52Soil Acidity Affects Plant Growth
- The performance of soil-applied herbicides can be
adversely affected - Reduced activity of symbiotic N fixing bacteria
- Clay soils high in acidity are less highly
aggregated - Availability of nutrients such as P, K and Mo is
reduced - Tendency for K to leach is increased
53How Lime Reduces Soil Acidity
- Ca2 ions from aglime replace Al3 at the
exchange sites. The Al3 reacts with water
releasing H - Carbonate ions (CO32-) from aglime react in the
soil solution, creating excess OH- (hydroxyl)
ions which combine with H ions forming water - The pH increases because the acidity source (H)
has been reduced
54Liming Materials
- Calcitic Lime
- Dolomitic Lime
- Hydrated Lime
- (Use 75 of the above recommended amount)
- Wood Ashes
- (Use with caution!)
55Relative Neutralizing Values of Some Common
Liming Materials
Relative Liming neutralizing material value,
Relative Liming neutralizing material value,
Calcium carbonate 100 Dolomitic
lime 95-108 Calcitic lime 85-100 Baked oyster
shells 80-90 Marl 50-90 Burned lime 150-175
Burned oyster shells 90-110 Hydrated
lime 120-135 Basic slag 50-70 Wood
ashes 40-80 Gypsum None By-products Variable
Relative neutralizing value is used
interchangeably here with calcium carbonate
equivalent
56Particle SizeDetermines Lime Reactivity
Lime reacted in 1 to 3 years,
Finer particle size (logarithmic scale of mesh
size)
57For best results, apply lime well ahead of
planting to allow sufficient time to neutralize
soil acidity
58Fertilizer grade (or analysis) refers to how much
of an element there is in a fertilizer based on
percentage by weight.
Fertilizer ratio describes the relative
proportions of N-P-K in a fertilizer.
59Fertilizer is referred to as
- Complete when it contains all three major plant
nutrients. - Incomplete when it lacks one of the major plant
nutrients. - Balanced when it contains equal amounts of N-P-K.
- Premium refers to fertilizers that contain the
minor elements - Slow release refers to fertilizers that release
the elements slowly over time
60Lets Do Some MATH
- Many fertilizer recommendation come as pounds of
(insert element) per 1000 square feet. - If you add that much product you will NOT get the
right amount because the product contains only a
percentage of the element. - So now what do you do?
61To determine the amount of ammonium sulfate a
5,000-sq ft lawn needs if the lawn requires one
lb of nitrogen per 1,000 sq ft...
- Lawn 5,000 sq. ft.
- Fertilizer Ammonium sulfate (21-0-0)
- Rate of Application 1lb of nitrogen per 1,000
sq. ft. - Ammonium sulfate is 21 nitrogen.
- 21 is the same as 0.21 or 21/100.
- This means for every 100 lb. of fertilizer
there are 21 lb. of nitrogen. - We need 1 lb of nitrogen for every 1,000 sq.
ft. Using proportions, we can calculate the
amount of ammonium sulfate needed to get 1 lb of
N. X represents the unknown amount being
calculated.
62Tims Method
To get the right amount of product take the
constant supplied on the right and divide by the
analysis of the element you want.
- ½ lb/1000 ft2 50
- 1 lb/1000 ft2 100
- 1.5 lb/1000 ft2 150
- 2 lb/1000 ft2 200
- 2.5 lb/1000 ft2 250
- See the pattern?
For the example to apply 1 lb of nitrogen /1000
ft2 using 21-0-0. 100/21 4.76 lbs of 21-0-0
per 1000 ft2.
63How much lime and fertilizer should I add to my
garden?
64Soil Test
Soil Test
Soil Test
Soil Test
Soil Test
65Soil testing is essential to applying the correct
fertilizer and Lime!
Adding fertilizer to the soil without testing is
like baking a cake without reading the recipe or
measuring the ingredients
66The greatest potentialfor error in soil
testingis in taking the sample
67A good sample is critical to getting a good soil
analysis!
68Sampling for Home Gardens and Lawns
- Consider different soils and management
situations that need to be sampled
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71Plant analysis and soil testing go hand-in-hand
72Soil Testing vs. Plant Analysis
- Soil testing and plant analysis are
complementary, but very different - Soil tests predict nutrient availability
- Plant analysis assesses nutrient uptake
- Soil tests are not always good predictors of
nutrients that leach easily, i.e. N or S - Plant analysis is a better tool to assess some
micronutrients, e.g. B, Fe, Mo
73Lets Review
- To a horticulturist what is soil?
- What is organic matter and what does it do for
the soil? - What is pH? What is buffer pH?
- How can I KNOW how much lime and fertilizer to
add?
74Other Recommended InformationFollow the Links
- Bob Lipperts Soil Page
- Indoor plants
- Fertilizing Lawns
- Mulch
- Fertilizing Trees
- Fertilizing Vegetables
- Home and Garden Information Center (HGIC)
- Soil testing
- Changing the pH of your soil
- Fertilizers
- Composting
75- www.clemson.edu/sandhill
- On the left you will see a link to the South
Carolina Master Gardener Program. - This program is available under both powerpoint
presentations and Electronic Training
76Credits
- I am not a soil scientist so much of this was
taken from several sources. Some of the
following are sources Ive stolen this
information from. Thanks to all who had a part.
- South Carolina Master Gardener Manual
- Home and Garden Information Center
(http//hgic.clemson.edu) - Bob Lipperts Powerpoint (Clemson University)
Slide Presentation - Michelle Clarks (Richland County Master
Gardener) MG Slide Presentation - Brian Smiths (Charleston County Extension Agent)
COTS Slide Presentation
77- This concludes our lesson.
If you have questions feel free to email me at
rdncn_at_clemson.edu