Problems and Solutionsby Tom Gibson

www.camaspermaculture.org

All over the country [some soils are] worn out, depleted, exhausted, almost dead. But here is

comfort: These soils possess possibilities and may be restored to high productive power, provided you do a

few simple things. —C.W. BURKETT, 1907

Definition of Soil*

SOIL—the natural medium in which plants grow.

This definition, however, may be a little too simple. Here’s a better one:

SOIL—a natural body that develops in profile form from a mixture of minerals and organic matter. It covers the earth in a very thin layer and supplies plants with air, water, nutrients, and mechanical support.

Our definition is, of course, the one we prefer:

SOIL—a living, dynamic system at the interface between air and rock. Soil forms in response to forces of climate and organisms that act on parent material in a specific landscape over a long period of time.

*Oregon State University Extension Service-Manual for Judging Oregon Soils.

Soil Components

Mineral MatterPore Space

OrganicMatter

Making a poor garden better often begins with the soil. If your garden soil is poor, consider giving it some help. Adding organic materials to sandy soils improves their nutrient- and water-holding capacity. Adding organic materials to clay soil improves drainage and aeration, and helps the soil dry out and warm up more quickly in the spring.

The soilecosystem

Residue decompositionNutrient cyclingAggregation and porosityEnhance plant growthBreak down contaminants

Bacteria, fungi, actinomycetes, protozoa, nematodes, arthropods, earthworms

Pictures courtesy M. Fauci and D. Bezdicek

Soil Organisms

Energy and nutrition in soils starts with organic matter. Maintaining organic matter helps soils release other nutrition through chemical action of humic acids and chemicals created by life forms that depend on organic matter.

Many plants develop a beneficial relationship with fungi that increases the contact of roots with the soil. Fungi infect the roots and send out root like structures called hyphae. The hyphae of these mycorrhizal fungi take up water and nutrients that can then feed the plant. This is especially important for phosphorus nutrition of plants in low-phosphorus soils. The hyphae help the plant absorb water and nutrients and in return the fungi receive energy in the form of sugars, which the plant produces in its leaves and sends down to the roots.

Root heavily infected with mycorrhizal fungi (note round spores at the end of some hyphae). Photo by Sara Wright.

The Soil Food Web

Water MovementHow quickly water moves through soil

Water Holding CapacityHow much water a soil can hold available for plant growth

Soil air and water

The plow is one of the most ancient and most valuable of man’s inventions; but long before he existed the land was in fact regularly ploughed, and continues tobe thus ploughed by earthworms.—CHARLES DARWIN, 1881

Pore space and air-water relations

Soil acts like a spongeMacro pores control infiltration and drainageCapillary pores control water holding capacityMicro pores hold unavailable water

Why are soils which in our father’s handswere productive now relatively impoverished?—J. L. HILLS, C. H. JONES, AND C. CUTLER, 1908

Soil properties that affect porosity

Soil textureSoil structureCompaction and disturbance

Organic matter

Soil Particle SizesSand .05-2 mmSilt .002-.05 mmClay <.002 mm

Coarse Fragments >2 mm

Approximate surface areas of 1 gram samples

Coarse sand Half Dollar

Fine clay Basketball court

Under the microscope, clay particles resemble playing cards in form. They are flat, hexagonal, and thin, like cards. When wet, the particles can 'slip' across each other, as in a deck of cards.

…with methods of farming in which grasses form an important part of the rotation, especially those that leave a large residue of roots and culms, the decline of the productive power is much slower than when crops like wheat, cotton, or potatoes, which leave little residue on the soil, are grown continuously. —HENRY SNYDER, 1896

Soil Minerals

What Kind of Soil Do I have?TextureStructureCompactionOrganic matter

The soil-fist test can be used to determine soil type. Compact wet soil in your fist to determine whether it is sandy, loam, or clay/silt. If it is sandy soil, it will refuse to form itself into a ball in your fist. If it is loamy, it will form itself into a ball, but remain friable so that it will crumble when poked with your finger. Clay/silty soil will form into a ball that has sufficient plasticity that it will remain a ball when poked with a finger. The more clay you have in your soil the longer the ribbon you can squeeze out.

TextureStructureCompactionOrganic matter

The depletion of the soil humus supply is apt to bea fundamental cause of lowered crop yields.—J.H. HILLS, C.H. JONES, AND C. CUTLER, 1908

Aggregation of sand, silt, and clay particles

Structure affects:Macro porosityInfiltrationAeration

Formation of soil structureGrowth of roots and movement of organisms

create pores and aggregatesSoil organisms break down organic residues,

producing glues that stabilize aggregatesFungi provide structural support to aggregatesPhysical, chemical processes also involved

Moisture, warmth, and aeration; soil texture; soil fitness; soil organisms; its tillage, drainage and irrigation; all these are quite as important factors in the make upand maintenance of the fertility of the soil as are manures, fertilizers, and soil amendments. —J.L. HILLS, C.H. JONES, AND C. CUTLER, 1908

Structure FactorsTextureStructureCompactionOrganic matter

Because organic matter is lost from the soil through decay, washing, and leaching, and because large amounts are required every year for crop production, the necessity of maintaining the active organic-matter content of the soil, to say nothing of the desirability of increasing it on many depleted soils, is a difficult problem.-- A. F. GUSTAFSON, 1941

Human compaction:Clearing Construction TrafficLivestock

Natural compaction:

Basal glacial till Very compact. Nearly impermeable.

Improving SoilsTextureStructureCompactionOrganic matterWhere no kind of manure is to be had, I think the cultivation of lupines will be found the readiest and best substitute. If they are sown about the middle of September in a poor soil, and then plowed in, they will answer as well as the best manure.—COLUMELLA, 1st Century, Rome

Using animal manure safelyIncorporate manure into

soil before planting.Wait AT LEAST 120 days

between application of fresh manure and harvest.

Well aged (>six months) and thoroughly composted manure do not have pathogen risk.

Don’t use cat, dog or swine manure.

Why is organic matter important?

Structure and macropores

Water holding capacity

InfiltrationNutrient supplyBiological activity

•Improved root environment

How does topography affect soil water?

… generally, the type of soil management that gives the greatest immediate return leads to a deterioration of soil productivity, whereas the type that provides the highest income over the period of a generation leads to the maintenance or improvement of productivity.—CHARLES KELLOGG, 1936

MicronutrientsBoronIronManganeseZincCopperChlorideMolybdenum

Plant NutrientsMajor NutrientsNitrogenPhosphorusPotassiumCalciumMagnesiumSulfur

About 90 nutrients found in soils are thought to affect health of animals and humans.

Bern Kohler, Ohio State Univ.

Chlorophyll - photosynthesis

Plant and Soil Sciences, U Nebraska

Amino acids and proteins

DNA

Amino Acid

Nutrient DeficienciesReduce plant growth, health, and yield.

Nutrient deficiencies can sometimes be identified by observing symptoms.

P deficiency in corn

Mg deficiency in corn

Problems with excess nutrients

Nitrogen:Plant health, fruit yield and quality

Groundwater qualityBoron:

Toxicity

Mineral Matter

Organic Matter

Mineral Matter

KMgCa

Organic Matter

N

SP

Nutrients

GenerallyNot

available

Notavailable

NS

P

soluble, available

KMgCa

K+ Ca++

Weathering

KMgCa

K+ Ca++

soluble, available

Weathering N

SP

Notavailable

Biological release

NH4+ SO4

-2

Fertilizer Labels 5 - 10 - 10

% N - % phosphate -% potashPhosphate = units of P

1 lb P = 2.3 lb phosphate (P2O5)Potash = units of K

1 lb K = 1.2 lb potash (K2O)

How much fertilizer do I use?

Fertilizer should be added after determining what the available amount of nutrition is.

The available amount is often less than the total amount.

Available phosphorous in the spring is often higher than the input amount after adding manure in the fall. Manure increases the biological activity in soil which liberates phosphate and other minerals that are “locked up”.

Soil pHIndicates relative acidity or

alkalinitypH 7 = neutral; less than 7 = acid;

more than 7 = alkaline or basicLogarithmic scale

Adapted from library.thinkquest.org

Why is pH important?Nutrient availabilityAvailability of toxic metalsMicrobiological activityAcids in soils generally result in higher levels of metals being available to plants like copper, a necessary nutrient for blueberries. Can also cause heavy metals that are toxic to humans and other animals to be more available. The widest amount of biological activity is seen in soils that have a near neutral pH.

Soil AcidificationA natural process in humid areasAccelerated by fertilizersSulfur and ammonium sulfate are strong acidifiers

Has a tendency to leach calcium and other rock minerals from soil

Desirable pH RangesVegetables 6 to 7.5Pastures 5.5 to 8Acid loving plants 4.5 to 5.5

Increasing pHLime (CaCO3) neutralizes acidityLime supplies Ca, which is often

deficient in acid soilsDolomite lime also supplies MgMagnesium may raise pH six

times faster than calciumApply lime based on soil test, and

lime only those crops that need it.For gardens without soil test: 50

lb/1000 sq ft/year

Taking a Sample1. Don’t wait until the last minute. The best time to sample for a general

soil test is usually in the fall. Spring samples should be taken early enough to have results in time to properly plan nutrient management for the crop season.

2. Take cores from at least 15 to 20 spots randomly over the field to obtain a representative sample. One sample should not represent more than 10 to 20 acres.

3. Sample between rows. Avoid old fence rows, dead furrows, and other spots that are not representative of the whole field.

4. Take separate samples from problem areas, if they can be treated separately.

5. In cultivated fields, sample to plow depth.

Taking a Sample6. Take two samples from no-till fields: one to a 6-inch depth for lime and

fertilizer recommendations, and one to a 2-inch depth to monitor surface acidity.

7. Sample permanent pastures to a 3- to 4-inch depth.8. Collect the samples in a clean container. 9. Mix the core samplings, remove roots and stones, and allow to air dry.10. Fill the soil-test mailing container.11. Complete the information sheet, giving all of the information requested.

Remember, the recommendations are only as good as the information supplied.

12. Sample fields at least every three years. Annual soil tests will allow you to fine-tune nutrient management and may allow you to cut down on fertilizer use.

—MODIFIED FROM THE PENNSTATE AGRONOMY GUIDE, 1999.

A & L Labs Complete Soil Test - 503-968-9225 http://www.al-labs-west.com

Kinsey Agricultural ServicesSoil fertility problems/Albrecht Method (feed the soil)http://www.kinseyag.com/

Wy’East Environmental Services Soil Lead Test - 503-231-9320 http://www.wyeastlab.net

Many soils require irrigation for maximum productivity. Both the

amount ofirrigation water needed and the

proper method of applying it depend on a soil’s permeability rate and

water-holding capacity.

Installing an irrigation system can save money/water and increase yields. It can also mitigate pest and disease problems caused by over or improper watering.

Drip or weep hose irrigation will maximize delivery of water and nutrients to the root zone while minimizing splashing and watering that causes disease. You can build simple effective systems with off the shelf components from hardware stores. A typical drip system can easily recapture the entire cost in a single season by limiting excessive watering while ensuring plants get the needed resources.

Best results will occur with the use of some kind of mechanical or electronic control system that measures the water or the amount of time the water is allowed to run.

Thank YouMaterial provided by:Dr. Craig Cogger-WSU/NRCS, PuyallupDr. Charles Brun-WSU Extension Clark CountyKinsey Agricultural ServicesNational Center for Appropriate Technology U. S. Department of Agriculture

Additional ResourcesUSDA National Agricultural Libraryhttp://www.nal.usda.gov/Building Soils for Better Cropshttp://www.sare.org/publications/bsbc/bsbc.pdf

Soil Survey of Clark Countyhttp://soildatamart.nrcs.usda.gov/Manuscripts/WA011/0/

wa011_text.pdfNRCS Soil Survey Explorerhttp://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspxGuide to Soil Survey Reportshttp://smallfarms.oregonstate.edu/sites/default/files/Soil_survey_brochure.pdfSustainable Agriculture Research and Education (SARE)http://www.sare.org/index.htmClayhttp://en.wikipedia.org/wiki/ClayNational Sustainable Agriculture Information Servicehttp://attra.ncat.org/soils.htmlOSU Extension Service-Improving Garden Soilhttp://extension.oregonstate.edu/catalog/html/grow/grow/soil.htmlSoil and Health Libraryhttp://www.soilandhealth.org

Additional Resources