Organic Gardening - Introductory Study of Soils

8/9/2019 Organic Gardening - Introductory Study of Soils

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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


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What We Will Cover Tonight

Introduction.

Ecological agriculture perspective tounderstanding the physical, chemical and

biological properties of soil for gardeners.

Compost basics for home and community

gardeners.


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Soil: the Foundation of

Gardening

WSH


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CEC

Air

MoistureMicrobes

OrganicM

atter

Structur

e

Texture

pH

Pollutants

Nutrients

A Simplified Soil Ecosystem


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Soil Fertility is

The ability of a soil to provide aphysical,

chemical, andbiological environment for

the plant that is health sustaining.

This is along term ecosystem based or

ecological agriculture perspective!


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Seven Principles to Maintain

Soil/Water/Plant Resource Base1. Maintain proper air/water balance

2. Maintain soil tilth

3. Prevent erosion

4. Maintain biological diversity

5. Maintain proper SOM levels

6. Maintain a proper pH7. Maintain a proper balance of nutrients

(A systems approach means you gotta do themall. Alone each will not build soil fertility.)


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A Good Loam Soil:

50% Solids

50% Pores

45% Mineral5% Organic Matter

25% Air

Big Pores

25% Water

Small Pores

So why is this important?


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Roots:

1 the plant

2 Absorb and

3 Exchange

4 Store and

5 Transform

6 Produce plant

7 Interact with

Support

water nutrients

gases

starches sugars

nutrients

hormones

microbes for disease suppression


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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


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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)


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Valley Clay Soils

Ap Topsoil Layer

(O Organic Matter tilled in)

E Leached Layer

B Clay Accumulations C Parent Material

(NRCS/USDA)


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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!


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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)


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Soil Particles That Make Up

Texture Feel: Sand

Silt

Clay

Not apart of Texture:

Organic Matter

Gritty

Smooth, like baking flour

Sticky

Greasy


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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!


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Soil Structure

*Granular, Crumb

*Platy

*Subangular Blocky

Angular Blocky

*Prismatic

Columnar

*Structureless

1. Single grained2. Massive

Shape of individual peds

* Note: found in Vermont


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You worked your soil when it

was too wet?What did you get?

You get: CLODS

It is called: PUDDLING YOUR SOIL


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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 Aint Got!*

Macropore hold air and drain (in-between)

Micropores hold water (inside)

OM = Drought Prevention Insurance


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Soil Too Dry?Manage to Prevent Water Loss By:

Mulching to conserve moisturePrevent runoff

Build OM content to improve the water

holding capacity

Control weeds (competition) or used them

to your advantagePlant tolerant species

Water deeply and consistently


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Soil Too Wet?

Manage for water loss by:Raised beds

Shape of beds

Follow good Management Practices

Add OM to improve drainage (clays)

Dont work wet soil

Plant after soil warms up

Plan wet in early spring areas for late season cropslike tomatoes

Plant tolerant species

Put in a drainage system to drop the water table


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2. Soil Tilth:

All the Physical Properties of SoilRelated to Plant Growth

Including: structure, drainage, aeration,moisture holding capacity, bulk density.

Work a soil when it has dried out enough

Add OM to improve physical properties

Treat soil gently

Keep soil covered


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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)


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Seven Principles to Maintain

Soil/Water/Plant Resource Base1. Maintain proper air/water balance

2. Maintain soil tilth

3. Prevent erosion

4. Maintain biological diversity5. Maintain proper SOM levels

6. Maintain a proper pH7. Maintain a proper balance of nutrients

i i i di i


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4. Maintain or Create Biodiversity

& SOIL


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& SOIL

DFW


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4. Maintain or Create BiodiversityRotate Crops

Plant Mixtures of Species

Interplant, Under-sow, Companion Plant, PolycultureAdd Compost

Mulch

Plant Biological or Ecological IslandsHabitat and Food For Beneficials

Selective Weeding

Change Tolerance Levels for Pest

Use IPM

Cautions?..

4 M i i C Bi di i


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4. Maintain or Create BiodiversityProvide Diverse Food: Organic Matter

Add Organic Residues

Add Manure or Compost

Grow Cover Crops

Provide Diverse HabitatRotate Crops; Include Cover Crops

Plant Mixtures of Species

Interplant, Under-sow, Companion Plant, Polyculture

Plant Biological or Ecological Islands; Habitat and Food ForBeneficial Organisms

Bio-strips, Flower Strips, Beetle Banks, Strip InsectaryIntercropping, Vegetative Corridors, Hedge Rows orSelective Weeding

Use Mulches; Reduce Tillage and Bare Land

Change Tolerance Levels for Pest

Reduce Chemical Inputs: Use Integrated Pest Management


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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


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H d R H bi


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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

l h bi


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Mulch as Habitat

Ground Beetles

Spiders

DFW

DFW

B l B k B i i


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Beetle Banks: Britain

Ground Beetles

and other

Predatory Beetles

http://www.orc.govt.nz/

Oregon State University Extension

www.snh.org.uk/

DFW


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Time for..

A. Questions?

B. A Break?

C. A Nap?

D. A Snack? Some Compost Tea?


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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


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What is Compost?

Compost is the biological reduction of

organic wastes to humus. (Golueke)

MICROBIAL ROT

Scientific American, 1991

P i i l f C ti


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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


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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.

Cornells WWW site for recipe design: http://compost.css.cornell.edu/science.html


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Moisture Balanced with O2

If hot compost is desired, a range of 50-60% ispreferred, but 40-65% is acceptable.

Field Test: Compost should feel like a dampsponge. Moist, but you cant ring water out of it.

Generally, if the C:N ratio is OK, moisture will beOK too.

Cornells WWW site for recipe design http://compost.css.cornell.edu/science.html

Particle size and thus pile porosity areimportant too!


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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 andactinomycetes

Less disease suppression

Mesophilic 50-105o

F 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-organismsinvolved

More disease suppression

SMB

SMB

SMB


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Troubleshooting Hot Compost

Wet and stinky?

Dry not working?

No heat when turned?

Add C materials and turnin sunny weather. Shapeto shed water. Break upmatting or compaction.

Add N materials and turnwhen raining. Shape to

hold water. Look at material if dark

and crumbly with goodearth smell, may becuring. No? Check sizeand consider additions.


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Management

VS.

.

Compost a Recipe for Trouble!


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Gardeners 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 seedor 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


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What Composting Does for You!

1. Decrease bulk of the pile (CO2 gas)

2. C:N ratio3. Odor

4. Hot composting kills weed seeds & pathogens

5. Cool composting provides disease resistance6. Humified (turning to humus) material is a slow

release fertilizer

7. Wastes become useful material

gardeners brown gold


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6. Maintain A Proper pH

Which is: pH

7. Maintain A Proper Balance of the

Nutrients

How to Know?

ESSENTIAL ELEMENTS FOR PLANT GROWTH


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Plant Available Major Source

Form of Nutrients

MACRO-NUTRIENTS

Carbon CO2 AirOxygen O2 Air

Hydrogen H2O Water

Nitrogen NO3-, NH4

+ Soil OM

Phosphorus H2PO4-, HPO4

2- Soil OM

Potassium K + Soil Minerals

Calcium Ca2+ Soil Minerals

Magnesium Mg2+ Soil Minerals

Sulfur SO42-

, SO2

(gas) Soil OM, Air

ESSENTIAL ELEMENTS FORPLANT GROWTH


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ESSENTIAL ELEMENTS FORPLANT GROWTH

MICRO-NUTRIENTS

Iron Fe2+ Soil Minerals + OM

Manganese Mn2+ Soil Minerals + OMCopper Cu2+ Soil Minerals + OM

Zinc Zn2+ Soil Minerals + OM

Boron H3BO3 Soil Minerals + OM*Molybdenum MoO4

2- Soil Minerals* + OM

Chlorine Cl- Soil Minerals + Rain*

Cobalt Co2+ Soil Minerals + OM

Nickel Ni2+ Soil Minerals + OM

OTHERS??

Sodium, Selenium, Silica, Vanadium, Iodine, Fluorine???

Plant Available Major Source

Form of Nutrients


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Soil Solution:

The Thin Skins of Water that CoatEverything.

Roo

tHair

C ti


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Cation

ExchangeCapacity +

++

+++ We arepositive!

Cations

K+ Mg2+ Ca2+ H+ Al3+

pH near neutral Acid pH

NO3-

A id


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The pH of

things in ourlives.

* 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

Neutral

Soils

Lemons

Lye

Ammonia

Milk of Magnesia

SeawaterBicarb of Soda

Vinegar, Grapefruit, Wine

Grass silage

TomatoesBeerBoric Acid

Human bloodManure

Cows milk

Distilled water

H+ + OH- = HOH = H2O

Acid + Base = Water


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pH Effects on Nutrient Availability


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pH

Prefere

ncesfo

rS

elec

ted

Pla

nts

(Foth, 1992)


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DO

YOUKNOW

Whats

In YourDirt

?

pH??

HeavyMetals??

N-P-K??

%OM??

Micron

utrients??


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http:/

/pss.uvm.

edu/ag_t

estin

g/forms.h

tml


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S il T t


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Soil Test

Report Soil Test Results

Recommendation Limestone

Nitrogen Phosphorus

Potassium

Management Info

Who to call

O k


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On Back

Interpretation of soil

test results to help

you figure out what

all this soil test

information means.


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Useful Soil Resources

Start with the Soil: The Organic Gardeners Guide toImproving Soil for Higher yields, More Beautiful Flowers, and

a Healthy Easy Care Gardenby Grace Gershuny.Rodale Press. 1993.

The Nature and Properties of Soilsby Nyle

C. Brady and Ray R. Weil. Prentice Hall.2002.

http://pss.uvm.edu/ag_testing/forms.html

U f l C t R


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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.

Cornells WWW site:

http://compost.css.cornell.edu/Composting_homepage.html

http://compost.css.cornell.edu/science.html


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Biological Slide References

DFW: The Decomposer Food Web: Ecologyof organisms of compost and soil litter by

Dr. Daniel Dindal, Professor Emertius, SoilEcologist, SUNY-Syracuse

SMB: Soil Microbiology and Biochemistryfrom Soil Science Society of America

WSH: Wendy Sue Harper, Ph.D.

More Questions on Soils or Compost?


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More Questions on Soils or Compost?

WSH

WSH

WSH

WSH

WSH


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The End

Organic Gardening - Introductory Study of Soils

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