Problems Pr oblems and Solutions by 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 Pore Space
Mineral Matter
Organic Matter
Making a poor garden better often begins with the soil. If your garden soil is poor, consider giving it some help. he lp. 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 ou t and warm up more quickly in the spring.
“Conventional” Agriculture Intensive tillage, soil erosion and insufficient insufficient added residues Soil organic matter decreases Surface becomes compacted, crust forms Most soil organic matter is lost Crop yields decline Aggregates break down Erosion by wind and water increases Less soil water storage, less diversity of soil organism, fewer nutrients for plants
The soil ecosystem
Residue decomposition Nutrient cycling Aggregation and porosity Enhance plant growth Break down contaminants
Soil Organisms
Bacteria, fungi, actinomycetes, protozoa, nematodes, arthropods, earthworms
Energy and nutrition in soils starts with organic matter. Maintaining organic matter helps soils release other nutrition through t hrough chemical action of humic acids and chemicals created by life forms that depend on organic matter.
The Soil Food Web
Root heavily infected with mycorrhizal fungi (note round spores at the end of some hyphae). Photo by Sara Wright.
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 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.
Soil air and water Water Movement
How quickly water moves through soil
Water Holding Capacity
How much water a soil can hold available for plant growth 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 to be thus ploughed by earthworms. —CHARLES DARWIN, 1881
Pore space and airwater relations Soil acts like a sponge Macro pores control infiltration and drainage Capillary pores control water holding capacity Micro pores hold unavailable water
Why are soils which in our father’s fat her’s hands were productive now relatively impoverished? —J. L. HILLS, C. H. JONES, AND C. CUTLER, 1908
Soil properties that affect porosity Soil texture Soil structure Compaction and disturbance Organic matter
Soil Particle Sizes
Sand .05-2 mm Silt.002Silt .002-.05 .05 mm Clay <.002 mm
Coarse Fragments >2 mm
Approximate surface areas of 1 gram samples Coarse sand Fine clay
Half Dollar 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.
Soil Minerals
…with methods of farming in which grasses form an important part of the t he 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
What Kind of Soil Do I have? Texture Structure Compaction Organic 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.
Texture Structure Compaction Organic matter
The depletion of the soil humus supply is apt to be a 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 porosity Infiltration Aeration
Formation of soil structure Growth of roots and movement of organisms create pores and aggregates Soil organisms break down organic residues, producing glues that stabilize aggregates Fungi provide structural support to aggregates Physical, 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 up and maintenance of the fertility of the soil s oil as are manures, fertilizers, and soil amendments. —J.L. HILLS, C.H. JONES, AND C. CUTLER, 1908
Structure Factors Texture Structure Compaction Organic matter
Because organic matter is lost from f rom the soil through decay, washing, and leaching, and because large amounts are required every year for crop cr op production, the necessity of maintaining the active organic-matter content of the t he soil, to say nothing of the t he desirability of increasing it on many depleted soils, is a difficult problem. -- A. F. GUSTAFSON, 1941
Human compaction: Natural compaction: Clearing Construction Basal glacial till Very compact. Traffic Nearly impermeable. Livestock
Improving Soils Texture Structure Compaction Organic matter Where 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 safely Incorporate 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 Infiltration Nutrient supply Biological 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
Plant Nutrients Major Nutrients
Micronutrients
Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur
Boron Iron Manganese Zinc Copper Chloride Molybdenum
About 90 nutrients found in soils are thought to affect health of animals and humans.
Chlorophyll photosynthesis Amino Acid
Amino acids and proteins
Plant and Soil Sciences, U Nebraska
DNA
Bern Kohler, Ohio State Univ.
Nutrient Deficiencies Reduce plant growth, health, and yield. P deficiency in corn Nutrient deficiencies can sometimes be identified by observing symptoms.
Mg deficiency in corn
Problems with excess nutrients Nitrogen:
Plant health, fruit yield and quality Groundwater quality
Boron:
Toxicity
Mineral Matter Organic Matter
K Ca
Mg
Mineral Matter
Nutrient s Generall yNot availabl e
N S
P
Organic Matter
Not available
N S
P Weathering
K Ca
Mg
K + Ca++ soluble,
Not available
Weathering
K Ca
Mg K + Ca++
N S
P
Biological release
NH4+ SO4-2
soluble, available
Fertilizer Labels
5-
10 - 10
% N - % phosphate -% potash Phosphate = units of P
1 lb P = 2.3 lb phosphate phosphate (P2O5) Potash = units of K
1 lb K = 1.2 lb potash (K 2O)
How much fertilizer do I use? Fertilizer should be added after determining what the available amount of nutrition is. i s. 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 pH Indicates relative acidity or alkalinity pH 7 = neutral; less than 7 = acid; more than 7 = alkaline or basic Logarithmic scale
Adapted from library.thinkquest.org
Why is pH important? Nutrient availability Availability of toxic metals Microbiological activity
Acids in soils generally result in higher levels of metals being available 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 Acidificati Acidification on A natural process in humid areas Accelerated by fertilizers Sulfur and ammonium sulfate are strong acidifiers Has a tendency to leach calcium and other rock minerals from soil
Desirable pH Ranges Vegetables 6 to 7.5 Pastures 5.5 to 8 Acid loving plants 4.5 to 5.5
Increasing pH Lime (CaCO3) neutralizes acidity Lime supplies Ca, which is often deficient in acid soils Dolomite lime also supplies Mg Magnesium may raise pH six times faster than calcium Apply 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 Sample 1.
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. depth.
Taking a Sample 6.
7. 8. 9. 10. 11.
12.
Take two samp Take samples les from from no-t no-till ill fiel fields: ds: one one to to a 6-inch 6-inch dept depth h for lime lime and fertilizer recommendations, and one to a 2-inch depth to monitor surface acidity. Samp Sa mple le per perma mane nent nt pas pastu ture res s to a 33- to 4-in 4-inch ch dep depth th.. Collllect Co ect th the e sam sampl ples es in a cle clean an co cont ntai aine ner. r. Mix the cor core e sampl sampling ings, s, remo remove ve roots roots and ston stones, es, and allo allow w to air air dry. dry. Fill the soil-t soil-test est mailin mailing g contain container. er. Complete Comple te the information information sheet, sheet, giving all of the informati information on requested. requested. Remember, the recommendations are only as good as the information supplied. Sample Sampl e fields at least least every three three years. Annual Annual soil tests tests will allow 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 Services Soil 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 of irrigation water needed and the proper method of applying it depend on a soil’s permeability rate and waterholding capacity.
Installing an irrigation system can save money/water and increase incr ease 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 You Material provided by: Dr. Craig Cogger-WSU/NRCS, Puyallup Dr. Charles Brun-WSU Extension Clark County Kinsey Agricultural Services National Center for Appropriate Technology U. S. Department of Agriculture
Additional Resources
USDA National Agricultural Library
http://www.nal.usda.gov/
Building Soils for Better Crops
http://www.sare.org/publications/bsbc/bsbc.pdf
Additional Resources
Soil Survey of Clark County
http://soildatamart.nrcs.usda.gov/ http://soildatamar t.nrcs.usda.gov/Manuscripts/WA011/ Manuscripts/WA011/0/wa011_text. 0/wa011_text.pdf pdf
NRCS Soil Survey Explorer
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx
Guide to Soil Survey Reports
http://smallfarms.oregonstate.edu/sites/default/file http://smallfarms.oregonstat e.edu/sites/default/files/Soil_survey_brochure.pdf s/Soil_survey_brochure.pdf
Sustainable Agriculture Research and Education (SARE)
http://www.sare.org/index.htm
Clay
http://en.wikipedia.org/wiki/Clay
National Sustainable Agriculture Information Service
http://attra.ncat.org/soils.html
OSU Extension Service-Improving Garden Soil
http://extension.oregonstate.edu/catalog/h http://extension.oregon state.edu/catalog/html/grow/grow/soil.html tml/grow/grow/soil.html
Soil and Health Library
http://www.soilandhealth.org
