The Living Soil

The world beneath our feetThe world beneath our feetPrepared byPrepared by

Pat Patterson, OSU Extension ServicePat Patterson, OSU Extension ServiceLane CountyLane County

Sustainable Human Environment

Ethic of caring for the earthEthic of caring for the earthInteracting with environment in mutually Interacting with environment in mutually beneficial waysbeneficial ways

Live Lightly on the Earth

Do not grow old, no matter how long you live.Do not grow old, no matter how long you live.Never cease to stand like curious childrenNever cease to stand like curious children

before the Great Mystery into which we were before the Great Mystery into which we were born.born.

––Albert EinsteinAlbert Einstein

Soil: Animal, Vegetable or Mineral?

Soil is now considered a partnership of Soil is now considered a partnership of many living and nonmany living and non--living factorsliving factorsWe need to consider the mineral part, the We need to consider the mineral part, the vegetable part and the living part.vegetable part and the living part.

Soil Is

A kind of placentaA kind of placentathat enables living things that enables living things

to feed upon the earth.to feed upon the earth.

The Traditional View of Soil

Soil is classified by textureSoil is classified by textureClay, silt and sandClay, silt and sand

ClayClay has the smallest particle size, highest has the smallest particle size, highest CECCECSiltSilt has midsize particle sizehas midsize particle sizeSandSand has the largest particle sizehas the largest particle size

How many soil types are there in Oregon?

There are nearly 2,000 different soils in There are nearly 2,000 different soils in Oregon alone, with approximately 15,000 Oregon alone, with approximately 15,000 soil series occurring worldwide.soil series occurring worldwide.

Dynamic System

Seasonal and eventSeasonal and event--oriented changesoriented changesMoisture, aeration, temperature (internal), Moisture, aeration, temperature (internal), nutrient availability, biological activitynutrient availability, biological activity

Inputs of organic matter (OM) & rainfallInputs of organic matter (OM) & rainfallLosses to leaching, volatilization (offLosses to leaching, volatilization (off--gassing), and erosiongassing), and erosionLongLong--term changesterm changes

Mineral composition & soil textureMineral composition & soil texture

The Dynamic soil System

The White House

A Limousine in front of the White

House

An Orange sitting on the seat of the

limousine

Clay

Clay feels sticky. It has the greatest water Clay feels sticky. It has the greatest water and nutrient holding capacity of all soil and nutrient holding capacity of all soil textures. It is the bank account of the soil.textures. It is the bank account of the soil.Unfortunately, clay is a miser, not wanting Unfortunately, clay is a miser, not wanting to let go of its wealth, so we add OM to to let go of its wealth, so we add OM to loosen its purse strings and avoid loosen its purse strings and avoid compaction.compaction.Wet clay forms a ribbon Wet clay forms a ribbon --or a potor a pot

Silty clay texture. This soil has 2% sand, 54% silt and 44% clay. It forms a ribbon nearly 3” long!

Feel the Clay

Silt

Silt feels like flour, smooth & slick.Silt feels like flour, smooth & slick.Silt may form a partial ribbon. It tends to Silt may form a partial ribbon. It tends to crust, but holds a medium amount of water crust, but holds a medium amount of water & nutrients.& nutrients.Silt is rarely found alone.Silt is rarely found alone.

Silty clay loam texture. This soil has 3% sand, 68% silt, and 29% clay..

Feels like Silt

SandSand feels gritty. It will form no ribbon.Sand feels gritty. It will form no ribbon.Sand has little capacity to hold water or Sand has little capacity to hold water or nutrients, almost no CEC.nutrients, almost no CEC.Adding OM allows the wellAdding OM allows the well--draining sand draining sand to also maintain its bank account.to also maintain its bank account.

Feel the Sand

Sandy loam texture. This soil has 73% sand, 23% silt and 4% clay..

Loam is not topsoil!

TextureTexture refers to the amounts of sand, silt refers to the amounts of sand, silt and clay in a soil.and clay in a soil.LoamLoam is a mixture of clay, silt and sand. is a mixture of clay, silt and sand. Thus we can have sandy loam, clay loam or Thus we can have sandy loam, clay loam or siltysilty loam.loam.The clay percentage should not exceed The clay percentage should not exceed 30%, 25% is preferable.30%, 25% is preferable.Topsoil is often from the bottom of a hole.Topsoil is often from the bottom of a hole.

Put it all TogetherMixing it up with soil

Feel test

Quart jar test

Altering soil textural properties

This is virtually impossible geologically!This is virtually impossible geologically!One acre of soil just 1 mm thick can weigh One acre of soil just 1 mm thick can weigh as much as five tons!as much as five tons!Some clays, when combined with sand, Some clays, when combined with sand, form a lowform a low--grade concrete!grade concrete!OM is the closest thing to a cureOM is the closest thing to a cure--all youall you’’ll ll ever find!ever find!

What is soil structure?

Soil structureSoil structure is how the individual soil bits is how the individual soil bits are bound together.are bound together.Good soil structure is called good Good soil structure is called good tilthtilth..Soil life stimulated by OM glues soil Soil life stimulated by OM glues soil particles into particles into ““pedspeds”” which then have good which then have good air and water pore space and thus, tilth.air and water pore space and thus, tilth.

Structural Type

Structural type refers to the shape of peds.Structural type refers to the shape of peds.Peds can be granular, platy, blocky or Peds can be granular, platy, blocky or prismatic.prismatic.Soils lacking peds can be described as either Soils lacking peds can be described as either massive (all one mass) or single grain (no massive (all one mass) or single grain (no cohesion at all.cohesion at all.

Porosity & Permeability

PorosityPorosity refers to the amount of space (pore refers to the amount of space (pore space) between particles in a soil.space) between particles in a soil.PermeabilityPermeability is how well water can move is how well water can move through that pore space.through that pore space.Good structure is associated with large Good structure is associated with large pores (pores (macroporesmacropores).).Soil life is essential to the formation and Soil life is essential to the formation and maintenance of good soil structure (tilth).maintenance of good soil structure (tilth).

What is CEC?

CEC stands for CEC stands for CationCation Exchange CapacityExchange Capacity. . A A cationcation is a positively charged ion.is a positively charged ion.It tells how well elements are held and It tells how well elements are held and swapped between the soil solution & soil swapped between the soil solution & soil surface. Elements are held to the soil by an surface. Elements are held to the soil by an electrical charge.electrical charge.It represents your bank account of nutrients It represents your bank account of nutrients from which you can draw.from which you can draw.

Nutrient Availability

98% of the minerals used by plants are taken up 98% of the minerals used by plants are taken up from the soil solution with the aid of soil from the soil solution with the aid of soil organisms.organisms.pH has a dramatic effect on nutrient availability!pH has a dramatic effect on nutrient availability!CationCation exchange occurs because of exchange occurs because of cationscations being being knocked off by competing knocked off by competing cationscations, but mainly by , but mainly by their being eaten and then released by soil life.their being eaten and then released by soil life.

Rule of nutrient availability

Soil pH

Measure of acidity (1Measure of acidity (1--14)14)Vegetables grow best at 6Vegetables grow best at 6--7 pH 7 pH Nutrients become available to plants in Nutrients become available to plants in soluble form as a result of work by soluble form as a result of work by microorganisms (hindered if too acid)microorganisms (hindered if too acid)Best to add lime in the fallBest to add lime in the fallAshes??Ashes??

pH effects on nutrient availability

pH over 7.0 is alkaline or sweet

pH under 7.0 is acid or sour

pH at 7.0 is neutral

To lower pH add sulfur, to raise pH add lime

Most plants prefer a pH of 6-7

Adding compost tends to balance soil at slightly acidic, just what most plants love!

Name some acid-loving plants, some lime loving plants.

What about gypsum?

Not west of the Cascades to soften clays!Not west of the Cascades to soften clays!Gypsum only works in soils high in sodium. Gypsum only works in soils high in sodium. These are usually found in areas of very low These are usually found in areas of very low rainfall.rainfall.Gypsum is Calcium sulfateGypsum is Calcium sulfateIt may be added to add Ca without changing It may be added to add Ca without changing pH. For example it can be used to give Ca pH. For example it can be used to give Ca to a rhododendron or blueberry.to a rhododendron or blueberry.

Water and soil

Water is held by cohesion & adhesion in the Water is held by cohesion & adhesion in the pore spaces. pore spaces. CohesionCohesion is water to water, is water to water, adhesionadhesion is water to soil particle.is water to soil particle.Plants can use only cohesive water. Clay Plants can use only cohesive water. Clay has lots of adhesive force.has lots of adhesive force.Excess water moves out by gravityExcess water moves out by gravity

How water moves

Water always fills like soil before moving into a Water always fills like soil before moving into a new type soil, whether from clay to sand or from new type soil, whether from clay to sand or from sand to clay when not in contact with free air.sand to clay when not in contact with free air.This is why we can create a clay pot in the soil by This is why we can create a clay pot in the soil by adding dissimilar material to the hole. The plant in adding dissimilar material to the hole. The plant in the hole may die of thirstthe hole may die of thirst--or drown!or drown!Unlike layers create a Unlike layers create a ““perchedperched”” water tablewater tablewhether in a pot or a yard.whether in a pot or a yard.

Water Demos

SpongeSpongeCupCupMovement of water in soilMovement of water in soil

Elements in Soil SuspensionThese elements are not attached to soil particles and are These elements are not attached to soil particles and are thus thus ““cash in handcash in hand”” for the plantfor the plant’’s use.s use.We need to capture any We need to capture any ““extrasextras”” so they do not leach into so they do not leach into the groundwater. the groundwater. Mobile in soil: Nitrogen, Sulfur, Mobile in soil: Nitrogen, Sulfur, ClorineClorine, Boron, Sodium, Boron, SodiumSomewhat immobile: Potassium, Calcium, MagnesiumSomewhat immobile: Potassium, Calcium, MagnesiumImmobile: Phosphorus, Iron, Manganese, Copper, Zinc, Immobile: Phosphorus, Iron, Manganese, Copper, Zinc, MolybdenumMolybdenumSoil should supply Soil should supply at leastat least 17 additional essential 17 additional essential plant nutrients.plant nutrients.

What about a soil sample?

Soil tests are not always necessary.Soil tests are not always necessary.Always sample at the same time of year.Always sample at the same time of year.Fall is a good time to sample, because slowFall is a good time to sample, because slow--acting amendments (such as lime) that need acting amendments (such as lime) that need to be added will have plenty of time to take to be added will have plenty of time to take effect over the winter.effect over the winter.Maintain good records!Maintain good records!

Learning to Know Your Soil

Run pH testRun pH testSoil judging (feeling & jar test)Soil judging (feeling & jar test)Observation of weeds and plant growthObservation of weeds and plant growth

Testing pHGetting to know your soil

Run pH testRun pH testSoil judgingSoil judgingObservation of weeds and plant growthObservation of weeds and plant growth

The Web of Life

It’s Alive!

Soil Life

Moles to microbes, the Moles to microbes, the soil is alive and soil is alive and teeming.teeming.Plant roots influence Plant roots influence other plants.other plants.If any part of the soil If any part of the soil web is disturbed, all web is disturbed, all parts are disturbed. parts are disturbed. Till as little as possibleTill as little as possible

The Big OM

Organic MatterOrganic Matter is the keystone of a live soilis the keystone of a live soilhelps soil form pedshelps soil form pedsimproves aeration, Himproves aeration, H22O penetration, HO penetration, H22O & O & nutrient retentionnutrient retentionprovides a bank of plant nutrientsprovides a bank of plant nutrientsbuffers chemical changes & detoxifiesbuffers chemical changes & detoxifiesincreases CECincreases CECis the energy source for soil is the energy source for soil biolifebiolife

The Web of Life

The live part of soil is temperature driven. It functions

best at 50oF or above. If the diverse population of microbes in

the soil were to fail in their functions, life for higher plants

and animals would cease.

Most beneficial organisms prefer aerated soil

How can we enhance beneficial Organisms in the soil?

Imitate nature.Imitate nature.Put back what you remove. Partially decomposed Put back what you remove. Partially decomposed OM is a major food source.OM is a major food source.Soil life needs Soil life needs allall the nutrient elements.the nutrient elements.Disturb the soil ecosystem as little as possibleDisturb the soil ecosystem as little as possibleHydroponic or mineral base media will grow Hydroponic or mineral base media will grow plants, but never be a balanced ecosystem.plants, but never be a balanced ecosystem.Respect how little we knowRespect how little we know

Why do early plants turn yellow or not thrive?

BPGT AND BPGG

Bug poop grows trees and gardens!Bug poop grows trees and gardens!MacroMacro--organisms in the soil include the organisms in the soil include the visible organisms from moles to mites.visible organisms from moles to mites.MicroMicro--organisms actually do most of the organisms actually do most of the work and are dominated by bacteria and work and are dominated by bacteria and fungi, although mites and other teeny fungi, although mites and other teeny critters plus the root hairs also function.critters plus the root hairs also function.

What do all these beings do?

Drive the fertilizer cycleDrive the fertilizer cycleAerate soilAerate soilAct as a catalystAct as a catalystAdd huge amounts of OMAdd huge amounts of OMPrevent diseasePrevent diseaseAct as a buffering agentAct as a buffering agentForm mycorrhizal associationsForm mycorrhizal associations

Fungal or Bacterial?

All living soils contain high populations of All living soils contain high populations of fungi and bacteria.fungi and bacteria.Whether the soil is primarily run by fungi or Whether the soil is primarily run by fungi or bacteria depends on the plant life present.bacteria depends on the plant life present.A forest is A forest is fungallyfungally dominated.dominated.A field or garden is A field or garden is bacteriallybacterially dominated.dominated.

Bacteria: the Horde

Bacteria do the lionBacteria do the lion’’s share of work in the s share of work in the soil. They will be present at 10soil. They will be present at 101212 close to the close to the roots of plants.roots of plants.Bacteria are the heaviest users of N at 5:1Bacteria are the heaviest users of N at 5:1A wellA well--balanced soil will have a balanced soil will have a preponderance of preponderance of ““goodgood”” bacteria, a killed bacteria, a killed soil will be soil will be recolonizedrecolonized by by ““badbad”” ones.ones.

Bacteria Work Hard

Fungi-the conveyer belt

Fungi have miles of mycelial strands in a Fungi have miles of mycelial strands in a healthy soil.healthy soil.Fungi enter into reciprocal agreements with Fungi enter into reciprocal agreements with the plants, as do the bacteria.the plants, as do the bacteria.Fungi extend the usable nutrient and water Fungi extend the usable nutrient and water area for a plantarea for a plant’’s roots.s roots.

Fungal Mycelium

Fungi Lassoing dinner

Ectomycorrhizae

It’s a “mitey” world

200 Different Mites in this picture

Tiny Critters at Work

Mites, springtails, Mites, springtails, psocidspsocids, millipedes, , millipedes, centipedes, ants, and their kincentipedes, ants, and their kin

Decomposer Mite

Springtail

Psocid

Millipede

Centipede

Harvester ants

Plant Talk

Plants may compete or cooperate.Plants may compete or cooperate.Plant roots exude substances. Plant roots exude substances. Plant roots attract other soil life forms.Plant roots attract other soil life forms.

Plant Partners?

Up to 60% of the plantUp to 60% of the plant’’s sugars go to the s sugars go to the roots and 1/2 of that is put into the soil roots and 1/2 of that is put into the soil medium to attract and feed bacteria and medium to attract and feed bacteria and fungi.fungi.The drawing in of the microThe drawing in of the micro--organisms then organisms then builds the soil structure, releases nutrients builds the soil structure, releases nutrients and minimizes diseases. Soil toxins are also and minimizes diseases. Soil toxins are also then broken down.then broken down.

Cover Crops

Cover crops :Cover crops :prevent erosion and compactionprevent erosion and compactionprovide for better air and water penetrationprovide for better air and water penetrationhold nutrientshold nutrientsproduce organic matter for next yearproduce organic matter for next yearprovide habitat for beneficial insectsprovide habitat for beneficial insectsreduce weed invasionreduce weed invasionmay even be ediblemay even be edible

Crimson Clover

Types of cover crops

Legume cover crops Legume cover crops add nitrogenadd nitrogenGrain cover crops add Grain cover crops add large amounts of OMlarge amounts of OMSmallSmall--flowered nectar flowered nectar crops enhance crops enhance beneficialsbeneficialsA mix is bestA mix is best

Winter Garden with Chickweed

Fertilizer: What and When

Seed is independentSeed is independentP 1P 1stst 15% of life15% of lifeMix some fertilizer Mix some fertilizer into the bottom of into the bottom of planting hole for planting hole for transplants.transplants.

Sidedress if not Sidedress if not enough residual enough residual nutrients (building nutrients (building blocks)blocks)N P K S Mg Ca major N P K S Mg Ca major elementselementsNeed Need allall elementselements

NitrogenNitrogen is both essential and most likely to cause Nitrogen is both essential and most likely to cause problems for plants and soilproblems for plants and soil

Needed for green growth. Speeds decomposition Needed for green growth. Speeds decomposition of OM.of OM.

Add N just before rapid vegetative growth, 3Add N just before rapid vegetative growth, 3--6 6 weeks after seeding or transplanting. Best to put weeks after seeding or transplanting. Best to put along row and water in.along row and water in.

Do not add N to seedling flats when seeded.Do not add N to seedling flats when seeded.

The Nitrogen Cycle

RootRoot--nodulatingnodulating rhizobiarhizobia bacteria found in bacteria found in legumes (e.g. peas, vetch, clover) are capable of legumes (e.g. peas, vetch, clover) are capable of fixing atmospheric Nfixing atmospheric N22 in the soil. Others work in the soil. Others work with other plants to do this (i.e. alder)with other plants to do this (i.e. alder)Nitrogen can also be lost to the atmosphere Nitrogen can also be lost to the atmosphere through processes such as through processes such as denitrificationdenitrification, a change , a change to gaseous form. (the ammonia smell from to gaseous form. (the ammonia smell from manures, for example)manures, for example)

Always incorporate N fertilizers!Always incorporate N fertilizers!Remember, donRemember, don’’t add (ammonium) fertilizers with t add (ammonium) fertilizers with liming materials!liming materials!

The Nitrogen Cycle

HereHere’’s another example of N cycling in the soil.s another example of N cycling in the soil.Bacteria have a C:N (carbon to nitrogen) of 5:1 Bacteria have a C:N (carbon to nitrogen) of 5:1 (narrowest known).(narrowest known).Protozoans have a C:N of 30:1.Protozoans have a C:N of 30:1.Protozoans release excess N after consuming Protozoans release excess N after consuming bacteria.bacteria.Adding N results in a decrease in OM due to Adding N results in a decrease in OM due to blooming bacterial populations.blooming bacterial populations.Do not overuse nitrogen!Do not overuse nitrogen!

The Nitrogen Cycle in Review

The N cycle is driven largely by the activity of soil The N cycle is driven largely by the activity of soil microbes.microbes.The activity of those same soil microbes is The activity of those same soil microbes is controlled by environmental factors such as controlled by environmental factors such as temperature and moisture.temperature and moisture.Thus the N cycle is dependent upon the same Thus the N cycle is dependent upon the same environmental factors that control the activity of environmental factors that control the activity of soil microbes and the growth of plants.soil microbes and the growth of plants.

PhosphorusPhosphorus may be of animal origin, Phosphorus may be of animal origin, ieiebone mealsbone mealsMined, i.e. rock or colloidal phosphateMined, i.e. rock or colloidal phosphate

Superphosphate (0Superphosphate (0--2020--0 plus Ca and S) or triple 0 plus Ca and S) or triple superphosphate (0superphosphate (0--4545--0) are classed as 0) are classed as synthetic because rock phosphate is treated with synthetic because rock phosphate is treated with sulfuric acid or with phosphoric acid. Both of sulfuric acid or with phosphoric acid. Both of these are much more likely to cause pollution.these are much more likely to cause pollution.Most is needed in the 1Most is needed in the 1stst 15% of annual15% of annual’’s life.s life.P is made most available through soil life.P is made most available through soil life.

Potassium

The original source was ashes, i.e. PotThe original source was ashes, i.e. Pot--Ash. This was Ash. This was formed by mixing ashes and hot water and filtering. The formed by mixing ashes and hot water and filtering. The resulting slurry was then dried. It contained most of the resulting slurry was then dried. It contained most of the minerals accumulated by the burned matter. Only 15# minerals accumulated by the burned matter. Only 15# woodash/1000 sq. ft./year in a garden.woodash/1000 sq. ft./year in a garden.Greensand is a mined potassium. Trace elements.Greensand is a mined potassium. Trace elements.Potassium sulfate is mined. It is soluble.Potassium sulfate is mined. It is soluble.SulSul--popo--magmag is a natural mineral salt.is a natural mineral salt.MuriateMuriate of Potash (potassium chloride) is a natural salt, but of Potash (potassium chloride) is a natural salt, but not allowed organically.not allowed organically.Most of our soils already have adequate K.Most of our soils already have adequate K.

Rule of nutrient availability

How Soil Dies

Compaction is one key (walking on, tilling Compaction is one key (walking on, tilling too much, leaving soil bare, especially in too much, leaving soil bare, especially in winter, working the soil at the wrong time)winter, working the soil at the wrong time)

Anything that removes the oxygen from soilAnything that removes the oxygen from soilNot having adequate Not having adequate biolifebiolife in the soil.in the soil.

Overcropping/MonocroppingOvercropping/Monocropping reduce OM reduce OM and soil life diversity. Soil biodiversity is and soil life diversity. Soil biodiversity is directly linked to plant biodiversity & tilth.directly linked to plant biodiversity & tilth.

BiocidesBiocidesThese are rarely used in the home garden any These are rarely used in the home garden any more and are becoming less used in commercial more and are becoming less used in commercial agriculture as well.agriculture as well.

Imbalance of nutrientsImbalance of nutrients--excess saltsexcess salts

Building the Web of Life

Life builds on organic matterLife builds on organic matterProper pH and water levels enhance lifeProper pH and water levels enhance lifeAvoid sudden shocks to the systemAvoid sudden shocks to the systemDiversity builds a healthy web of life below Diversity builds a healthy web of life below

and above the soil line.and above the soil line.Diversity of nutrients and of plantsDiversity of nutrients and of plants

Research shows that the nutritional quality of the plant, the defense systems of the plant, the immune systems of the plant eaters and the susceptibility of the plant to diseases and insects may all hinge on the BALANCE in the growing medium.

……I seem to have been only like a boy I seem to have been only like a boy playing on the sea shore, and diverting playing on the sea shore, and diverting myself in now and then finding a myself in now and then finding a smoother pebble or a prettier shellsmoother pebble or a prettier shell……, , whilst the great ocean of truth lay all whilst the great ocean of truth lay all undiscovered before me.undiscovered before me.

----Isaac NewtonIsaac Newton(Also the Master Gardener (Also the Master Gardener ™™ motto)motto)

The End...or just the beginning?

we may be able to decidewe may be able to decide

Bibliography

EdaphosEdaphos: Dynamics of a Natural Soil : Dynamics of a Natural Soil SystemSystem by Paul D. Sachsby Paul D. SachsTeaming with Microbes: A GardenerTeaming with Microbes: A Gardener’’s s Guide to the Soil Food Web Guide to the Soil Food Web by Jeff Lowenfels and Wayne LewisAn Agricultural Testament by Sir Albert Howard www.soilfoodweb.com