introductory study of soils - dphu...introductory study of soils for the master gardeners wendy sue...
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Introductory Study of Soils
For the Master Gardeners
Wendy Sue Harper, Ph.D.Vegetable and Fruit TA Advisor
Northeast Organic Farming Association of Vermont
www.nofavt.org
What We Will Cover Tonight• Introduction.• Ecological agriculture perspective to
understanding the physical, chemical and biological properties of soil for gardeners.
• Compost basics for home and community gardeners.
Soil: the Foundation of Gardening
WSH
A Plant & Soil Ecosystem Light
Air
Water, etc
Nutrients
pH
CEC
Moisture
Microbes, Earthworms, etc OM = Organic Matter
Temperature
AirTexture
Structure
Pollutants
CEC
Air
MoistureMicrobes
Organic Matter
Structu
re
TexturepH
Pollutants
Nutrients
A Simplified Soil Ecosystem
Soil Fertility isThe ability of a soil to provide a physical,
chemical, and biological environment for the plant that is health sustaining.
This is along term ecosystem based or ecological agriculture perspective!
Seven Principles to Maintain Soil/Water/Plant Resource Base
1. Maintain proper air/water balance2. Maintain soil tilth3. Prevent erosion4. Maintain biological diversity5. Maintain proper SOM levels6. Maintain a proper pH7. Maintain a proper balance of nutrients
(A systems approach means you gotta do them all. Alone each will not build soil fertility.)
A Good Loam Soil:
50% Solids
50% Pores
45% Mineral5% Organic Matter
25% AirBig Pores
25% WaterSmall Pores
So why is this important?
Roots:
1 the plant2 Absorb and3 Exchange4 Store and 5 Transform6 Produce plant 7 Interact with
Support
water nutrients
gasesstarches sugars
nutrients
hormonesmicrobes for disease suppression
An Undisturbed Soil Profile:
Ap
Zone of accumulation
Zone of biological activity
Organic matter
Mix O + A + E = Ap A = topsoil p = plowed or disturbed
Mountain Forest Sandy Soils
• O Organic Matter or A Topsoil Layer
• E Leached Layer• B Accumulations of
Iron, Aluminum and Organic Acids
• C Parent Material
(NRCS/USDA)
Valley Clay Soils
• Ap Topsoil Layer (O Organic Matter tilled in)
• E Leached Layer• B Clay Accumulations • C Parent Material
(NRCS/USDA)
1.Air/Water Balance Depends On:
1 Location on the landscape
2 Soil depth
3 Soil texture(lines=surface area)
4 Soil structure: inside vs. in-between
5 Soil organic matter content: it holds water!
Soil Textural Triangle:
*Loam Soil: The influence of the sand, silt and clay on its physical properties is equal. (Not the quantity or amount, but its influence!)
Here, amounts are equal.
(Brady and Weil, 2002)
Soil Particles That Make Up Texture Feel:
• Sand
• Silt
• Clay
Not apart of Texture:Organic Matter
Gritty
Smooth, like baking flour
Sticky
Greasy
1.Air/Water Balance Depends On:
1 Location on the landscape
2 Soil depth
3 Soil texture(lines=surface area)
4 Soil structure: inside vs. in-between
5 Soil organic matter content: it holds water!
Soil Structure
*Granular, Crumb
*Platy
*Subangular Blocky
Angular Blocky
*Prismatic
Columnar
*Structureless1. Single grained2. Massive
Shape of individual peds
* Note: found in Vermont
You worked your soil when it was too wet?
What did you get?
• You get: CLODS
• It is called: PUDDLING YOUR SOIL
Promote Structure With OM Additions• And Thus:
– Drainage in clay soils (macropores) – Water holding capacity in sandy soils (micropores)
*Cause it Creates the Pores You Ain’t Got!*
Macropore hold air and drain (in-between)Micropores hold water (inside)
OM = Drought Prevention Insurance
Soil Too Dry?Manage to Prevent Water Loss By:
Mulching to conserve moisturePrevent runoffBuild OM content to improve the water holding capacityControl weeds (competition) or used them to your advantagePlant tolerant speciesWater deeply and consistently
Soil Too Wet?Manage for water loss by:
Raised bedsShape of beds
Follow good Management PracticesAdd OM to improve drainage (clays)Don’t work wet soilPlant after soil warms upPlan “wet in early spring” areas for late season crops like tomatoes
Plant tolerant speciesPut in a drainage system to drop the water table
2. Soil Tilth: All the Physical Properties of Soil
Related to Plant Growth
• Including: structure, drainage, aeration, moisture holding capacity, bulk density….
Work a soil when it has dried out enoughAdd OM to improve physical propertiesTreat soil gentlyKeep soil covered
3. Prevent Erosion:Erosion is the process of detachment and
transport by wind or waterPrevent it by:
Make the wind or water less erosive by slowing it down.
Protect the soil from exposure to wind or water.
Build the soils resistance to erosive forces. (Brady and Weil, 2002)
Seven Principles to Maintain Soil/Water/Plant Resource Base
1. Maintain proper air/water balance2. Maintain soil tilth3. Prevent erosion4. Maintain biological diversity5. Maintain proper SOM levels6. Maintain a proper pH7. Maintain a proper balance of nutrients
4. Maintain or Create Biodiversity
& SOIL
DFW
4. Maintain or Create BiodiversityRotate CropsPlant Mixtures of Species
Interplant, Under-sow, Companion Plant, PolycultureAdd CompostMulchPlant Biological or Ecological Islands
Habitat and Food For BeneficialsSelective Weeding
Change Tolerance Levels for PestUse IPM
Cautions?…..
4. Maintain or Create BiodiversityProvide Diverse Food: Organic Matter
Add Organic ResiduesAdd Manure or CompostGrow Cover Crops
Provide Diverse HabitatRotate Crops; Include Cover CropsPlant Mixtures of Species
Interplant, Under-sow, Companion Plant, PolyculturePlant Biological or Ecological Islands; Habitat and Food For Beneficial Organisms
Bio-strips, Flower Strips, Beetle Banks, Strip InsectaryIntercropping, Vegetative Corridors, Hedge Rows or Selective Weeding
Use Mulches; Reduce Tillage and Bare LandChange Tolerance Levels for Pest
Reduce Chemical Inputs: Use Integrated Pest Management
Biological or Ecological Islands
www.sare.org
Syrphid Fly
Lacewings
Parasitic Wasp
www.attra.orgwww.sare.org
www.sare.org
NCSU-IPM
NCSU-IPM
NCSU-IPM
www.sciencemuseum.org.uk
Refugia or Conservation Head Lands
www.sare.org
University of Minnesota Extension
NCSU-IPM
www.sare.org
www.ukagriculture.com
Hedge Rows as Habitat
Wind Shelter Belt
Vegetation Barriers
Vegetative Corridors
Spined Soldier Bug
Praying Mantis
USDA/NRCS/NAC
National Corn Growers Association
Texas A&M University
University of Idaho
www.sare.org
Mulch as Habitat
Ground Beetles
Spiders
DFW
DFW
Beetle Banks: Britain
Ground Beetles and other Predatory Beetles
http://www.orc.govt.nz/
Oregon State University Extension
www.snh.org.uk/
DFW
Intercropping: Living Mulches
Bigeyed BugRover BeetleMinute Pirate Bug
NCSU-IPMwww.omafra.gov.on.ca/
www.dereila.ca
www.sare.org
Time for……..
A. Questions?
B. A Break?
C. A Nap?
D. A Snack? Some Compost Tea?
5. How Can You Get OM Into Your Soils?
Animal Manures
Composts
Cover Crops
Mulches
Peat Moss
Others?
Any Cautions? ……C:N Ratio or Carbon to Nitrogen Ratio
What is Compost?
• Compost is the biological reduction of organic wastes to humus. (Golueke)
MICROBIAL ROT
Scientific American, 1991
Principles of Composting• C:N Ratios
– Recipe• Moisture Balanced with Oxygen
– Recipe– Particle Size
• Temperature – Recipe– Size of pile– Microbes and Macrobes– Time
• Management– Assess Your Level of Interest
C:N Ratio• If hot compost is desired, the ratio preferred is
about 25-30:1, but 20-40:1 is acceptable.• High C Materials: straw, hay, woody materials,
dried corn stalks, paper wastes.– Not are Carbon behaves the same.
• High N Materials: manures, green material, food wastes.
• Start with 1 handful of N wastes to 3 of C wastes.• Cornell’s WWW site for recipe design:
– http://compost.css.cornell.edu/science.html
Moisture Balanced with O2
• If hot compost is desired, a range of 50-60% is preferred, but 40-65% is acceptable.
• Field Test: Compost should feel like a damp sponge. Moist, but you can’t ring water out of it.
• Generally, if the C:N ratio is OK, moisture will be OK too.
• Cornell’s WWW site for recipe design – http://compost.css.cornell.edu/science.html
• Particle size and thus pile porosity are important too!
Temperature• Thermophilic over 105o F
– Recipe more critical– Size is important– Quicker– More management– More labor– Destroys weed seeds– Destroys pathogens– Mainly microorganisms:
Mostly BACTERIA, Some fungi and actinomycetes
– Less disease suppression
• Mesophilic 50-105oF– Recipe less critical– Size is not important– Slower– Less management– Less labor– May not destroy weed
seeds and pathogens – Diversity of both micro
and macro-organisms involved
– More disease suppression
SMB
SMB
SMB
Troubleshooting Hot Compost• Wet and stinky?
• Dry not working?
• No heat when turned?
• Add C materials and turn in sunny weather. Shape to shed water. Break up matting or compaction.
• Add N materials and turn when raining. Shape to hold water.
• Look at material if dark and crumbly with good earth smell, may be curing. No? Check size and consider additions.
Management
VS.
.
Compost a Recipe for Trouble!
Gardener’s Easy Practical Compost Method • In bins or free standing.• Build pile by adding 1 handful
of green/wet stuff for every 3 handfuls of brown/dry stuff, added overtime.
• Add soil/old compost for odor control.
• Turn and rebuild pile in fall, mix in garden cleanup debris.
• Wait 2-3 years before using.• Do not add weeds gone to seed
or plants infected with viruses.
ORGANIC MATERIALS
ORGANIC MATERIALS - Grass, leaves, weeds, etc.
ORGANIC MATERIALS
1-2” manure
Cross Section of Layering in Compost Bin
1-2”
6-8”
SOIL
SOIL
SOIL
SOIL LINE
What Composting Does for You!1. Decrease bulk of the pile (CO2 gas)2. C:N ratio3. Odor 4. Hot composting kills weed seeds & pathogens5. Cool composting provides disease resistance6. Humified (turning to humus) material is a slow
release fertilizer7. Wastes become useful material
gardener’s brown gold
6. Maintain A Proper pH
Which is: pH
7. Maintain A Proper Balance of the Nutrients
How to Know?
Plant Available Major SourceForm of Nutrients
MACRO-NUTRIENTSCarbon CO2 AirOxygen O2 AirHydrogen H2O Water
Nitrogen NO3-, NH4
+ Soil OMPhosphorus H2PO4
-, HPO42- Soil OM
Potassium K+ Soil Minerals
Calcium Ca2+ Soil MineralsMagnesium Mg2+ Soil MineralsSulfur SO4
2-, SO2 (gas) Soil OM, Air
ESSENTIAL ELEMENTS FOR PLANT GROWTH
ESSENTIAL ELEMENTS FOR PLANT GROWTH
MICRO-NUTRIENTSIron Fe2+ Soil Minerals + OMManganese Mn2+ Soil Minerals + OMCopper Cu2+ Soil Minerals + OMZinc Zn2+ Soil Minerals + OMBoron H3BO3 Soil Minerals + OM*Molybdenum MoO4
2- Soil Minerals* + OMChlorine Cl- Soil Minerals + Rain*Cobalt Co2+ Soil Minerals + OMNickel Ni2+ Soil Minerals + OM
OTHERS??Sodium, Selenium, Silica, Vanadium, Iodine, Fluorine???
Plant Available Major SourceForm of Nutrients
Soil Solution:The Thin Skins of Water that Coat
Everything.Roo
t Hair
CationExchangeCapacity +
++
+++ We are positive!
Cations
K+ Mg2+ Ca2+ H+ Al3+
pH near neutral Acid pH
NO3-
The pH of things in our lives.
* Distilled water or rain water = pH 5.6
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
pH Acid
Basic
NeutralSoils
Lemons
Lye
AmmoniaMilk of Magnesia
SeawaterBicarb of Soda
Vinegar, Grapefruit, Wine
Grass silageTomatoesBeerBoric Acid
Human bloodManure
Cows milkDistilled water
H+ + OH- = HOH = H2OAcid + Base = Water
pH Effects on Nutrient Availability
pH P
refe
renc
es fo
r Sel
ecte
d Pl
ants
(Foth, 1992)
DOYOU
KNOWWhat’sIn Your
Dirt?
pH??
Heavy Metals??
N-P-K??
% OM??
Micronutrients??
http:/
/pss.u
vm.ed
u/ag_
testin
g/form
s.htm
l
Soil Test Report
• Soil Test Results• Recommendation
– Limestone– Nitrogen– Phosphorus– Potassium
• Management Info• Who to call
On Back
• Interpretation of soil test results to help you figure out what all this soil test information means.
Useful Soil Resources• Start with the Soil: The Organic Gardener’s Guide to
Improving Soil for Higher yields, More Beautiful Flowers, and a Healthy Easy Care Garden by Grace Gershuny. Rodale Press. 1993.
• The Nature and Properties of Soils by NyleC. Brady and Ray R. Weil. Prentice Hall. 2002.
http://pss.uvm.edu/ag_testing/forms.html
Useful Compost Resources• The Rodale Book of Composting
by Deborah L. Martin & Grace Gershuny. Rodale Press. 1992.
• On-Farm Composting Handbook by Robert Rynk. NRAES-54. 1992.
• Cornell’s WWW site:– http://compost.css.cornell.edu/Composting_homepage.html– http://compost.css.cornell.edu/science.html
Biological Slide References• DFW: The Decomposer Food Web: Ecology
of organisms of compost and soil litter byDr. Daniel Dindal, Professor Emertius, Soil Ecologist, SUNY-Syracuse
• SMB: Soil Microbiology and Biochemistry from Soil Science Society of America
• WSH: Wendy Sue Harper, Ph.D.
More Questions on Soils or Compost?
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The End