soil health: a permaculture approach

Soil Health a permaculture approach

Thursday, March 17, 2011

“When the earth is rich it bids defiance to

droughts, yields in abundance, and of the best

quality. I suspect that the insects which have

harassed you have been encouraged by the

feebleness of your plants, and that has been

produced by the lean state of your soil.”

Thomas Jefferson, in an 1793 letter to his

daughter advising her on pest problems


Where does soil come from?


What is soil?Soil is composed of the following:

mineral solids- sand, silt, and clay

water- main source of water for plants (contains

dissolved nutrients)

air- provides roots with oxygen and helps remove

excess carbon dioxide from respiring root cells

organic matter- composed of living organisms

(living), fresh residues (dead), and well

decomposed residues (very dead)


Major Soil Nutrients

Nitrogen (N)- Promotes plant growth

Phosphorus (P)- Helps plant transfer energy from

sunlight to the plant

Potassium (K)- Thickens cell walls helps plant fight

diseases and pests


Secondary NutrientsCalcium (Ca)- for cell division, root tip growth,

genetic coding, and neutralizing imbalances of

other nutrients

Magnesium (Mg)- for chlorophyll

Sulphur (S)- production of flavor and odor

compounds and protein


Trace Elements

Iron, Zinc, Boron, Copper, Manganes and 40

others


Organic MatterLiving contains a wide variety of microrganisms

including bacteria, fungi, protozoa, algae, insects,

earthworms, moles. They help break down crop

residues, manures and mix them with the minerals in

the soil. In doing so they recycle plant nutrients.

Worms and fungi stabilize soil by producing channels to

allow water to infiltrate.

Dead organic matter provides food to living organisms.

The Very Dead is also called humus: it stores water

and nutrients for plant life.


The soil food web maps out the web of symbiotic relationships of soil organisms. Not only do these organisms help break down organic matter and transform it to humus, they also act as food for each other.


What does healthy soil do?

Stores and recharges groundwater- prevents flo

Retains nutrients that feed plants

Cleans toxins

Stores carbon

Can be used as a building material


What is the problem?


Eutrification and Soil Compaction:


BLUE GREEN ALGAE ON LAKE

WINNIPEGFLOODED FACTORY HOG FARM

PHOTO SOURCE: GREEN PEACE CANADA


Strategies for building healthy soil

No or low till methods of food production- Sheet

mulching, double digging, keyline plow.

Feed the Soil-Non chemical fertilizers- compost,

compost teas, other plant based fertilizers

Rotational animal grazing

Add organic matter in soil

Cover bare soil- cover crops, organic mulch or low

growing groundcover plants

Depave


No and Low till methodsSheet Mulching- Building soil up mimics the way

the forest builds soil by dropping leaves. Also

called lasagna gardening. A process of laying

down a barrier layer (often newspaper or

cardboard) and alternating layers of carbon

(browns) and nitrogen (greens)

Double Digging- To double dig is to remove a layer

of topsoil to "spade depth" - 8 in. to 12 in., roughly

the length of a spade's blade--and set it aside.

Then, the next 8-in. to 12-in. layer of soil, the

subsoil, is loosened, aerated. Finally, the top layer is

put back in place.


Sheet Mulching


Sheet Mulching-Multiple FunctionsRapidly increases topsoil growth

Removes organic material from landfill

Provides habitat for worms

Slow yielding of nutrients over time

Human energy intensive (opportunity for building

community)

Absorbs, stores and slowly releases water


Rotational Grazing

SHEEP ARE ROTATED AROUND

FIELDNEXT CHICKENS FOLLOW SHEEP


Rotational Grazing

Sheep (or other ruminent), graze pasture and are

moved before they have damaged forage. (see

image above)

Chickens follow, spread sheep manure and eat

harmful parasites that may be living in manure.

Process is repeated once pasture has grown back.


Example of non- chemical fertilizersFeeds the soil microrganisms!

Liquid Fertilizers

Compost

Rock dust and other sources of macro and micro

nutrients

See reading, “Make your own liquid garden

fertilizers,” by Mark Krawcyk


DepavingTransforms urban spaces into community assets

Increases water infiltration

Decreases Combined Sewer Overflow events

See depave video


soil health: a permaculture approach

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