NOFA
Standards for Organic Land Care
Practices
for Design and Maintenance of Ecological Landscapes
By the Northeast Organic Farming Association (NOFA)
Organic Land
Care Program
Sarah Little,
PhD, Chair
4th
Edition Contributors (listed alphabetically):
Tim Abbey,
Donald Bishop,
Gardens Are...,
Christian G. Curless,
Dr. Sharon Douglas,
Bill Duesing,
Donna Ellis,
Todd Harrington,
Harrington’s Safelawns,
Rose Hiskes,
Don Franczyk, Baystate Organic Certifiers, Winchendon MA
Ashley
Kremser, NOFA Organic Land Care Program,
Kathy Litchfield, NOFA/Mass, Petersham MA
Marissa Lupia,
Environmental Advocacy and Organizing Program,
Dr. Leslie
Mehrhoff,
Michael Nadeau,
Plantscapes, Inc.,
Dina Pelletier,
MPH, Edible Organic Design,
Robert J. Rafka, Ph.D, URI
Master Gardener, Stonington, CT
Brad Robinson,
Connecticut Department of Environmental Protection,
Barbara Schlein,
Fountain Gardening Services,
Mary Tyrrell,
Camilla Worden,
Priscilla Williams, Pumpkin Brook Organic Gardening, Inc., Townsend MA
Acknowledgements
The
first edition of the Standards
was prepared for publication and published with assistance from the New England
Grassroots Environmental Fund. We are
very grateful for their support. We are
also grateful for the support of The
Antioch University New England Advocacy Clinic and Marissa Lupia for her
hard work, research, and contributions to this fourth edition.
The Committee wishes to thank the
following people for their technical input and review of the early drafts of
the Standards: Nancy DuBrule, Natureworks; Karl Guillard,
University of Connecticut; Kathy Johnson, USDA Natural Resources Conservation
Service; Tom Morris, University of Connecticut; Julie Rawson, NOFA/Mass; Peter
Rothenberg, CT NOFA; and Nancy Stoner, Clean Water Program, Natural Resources
Defense Council.
NOFA Standards for
Organic Land Care....................... 1
Purpose of Standards........................................................................................................... 8
OLC Standards and the National
Organic Program (NOP)..................................................
9
Accreditation by NOFA to Provide
Organic Land Care...................................................... 10
Compost............................................................................................................................ 21
Compost Tea..................................................................................................................... 23
Manure.............................................................................................................................. 24
Nitrogen............................................................................................................................. 25
Phosphorus........................................................................................................................ 26
Potassium........................................................................................................................... 27
Blended Fertilizers.............................................................................................................. 29
Planting and Plant Care......................................................................................................... 31
Cover Crops, Green Manures And Crop
Rotations............................................................. 32
Pruning............................................................................................................................... 33
The
Cultivar Debate............................................................................................................ 41
Why Native Species........................................................................................................... 42
What
is Native.................................................................................................................... 42
Treatment of Existing Invasive Plants................................................................................... 43
Insects and Other Arthropods............................................................................................. 51
Snails & Slugs.................................................................................................................... 53
Disease Control....................................................................................................................... 54
Disposal Guidelines
For Garden Renovation Projects......................................................... 57
Horticulture/Pest Management Related
Web Sites............................................................... 65
Soil Testing Laboratories.................................................................................................... 66
Lists of Plants Preferred and Not
Preferred by Wildlife........................................................ 73
Organic Land Care Accreditation Form.............................................................................. 75
NOFA
MANURE COMPOSTING RECORD.................................................................. 79
NOFA
ALLOWED PRACTICES RECORD.................................................................... 80
NOFA
LIST OF PROHIBITED PRACTICES AND
MATERIALS.................................. 81
US EPA - Office of Pesticide Programs
List of Inert Pesticide Ingredients........................ 87
Principles
of Organic Land Care
The
mission of the
The Organic Land Care Program, formed
in 1999, has developed these standards as part of the process of educating land
care professionals about the meaning of the word “organic” and to present our
vision of how these principles can be applied to the landscaping profession.
Through an education and accreditation program, we hope to make available to
the public landscaping services that will meet or exceed the standards
presented here. We also hope to educate the public about the meaning of
“organic” and the benefits of this option for care of the land around their own
homes, neighborhoods, and communities.
Basic
Principles of Organic Land Care
Adapted from the
“Principles of Organic Agriculture,” International Federation of Organic
Agriculture Movements (IFOAM)
1. Principle of
health. Organic Land Care should sustain and enhance
the health of soil, plant, animal, human, and planet as one and indivisible.
2. Principle of
ecology.
3. Principle of
fairness.
4. Principle of
care.
Health
Health is not simply
the absence of illness, but the maintenance of physical, mental, social, and
ecological well-being. Our role is to sustain and enhance the health of
ecosystems and organisms from the smallest in the soil to human beings, and
with the future of the planet in mind. We seek to maintain and increase the
long-term health of soils, and the diversity, resilience and sustainability of
ecosystems. We strive to avoid all forms
of pollution in the establishment and care of landscapes.
Right Plant,
Plant health depends
on growing the plant in the right place and in healthy soil appropriate to the
habitat and needs of the plant. Plants have evolved to occur in certain
niches in the landscape. Choosing plants
suited to a specific site, rather than modifying a site for the plants, is the embodiment of “Right Plant,
Ecology
We seek to work with
natural systems rather than trying to dominate them, and to encourage and
enhance biological cycles involving microorganisms, soil flora and fauna,
plants, and animals. These cycles are
universal, but their operation is site-specific. We work as much as possible within a closed
system with regard to organic matter and nutrient elements, and, when inputs
are needed, to use renewable resources from local sources. We must protect the diversity of the land and
its surroundings, including protection of native plant and wildlife habitats.
Fairness
An
integral part of organic land care is stewardship of the earth’s inhabitants,
including humankind. To be an organic land care employer entails a strong
belief in this ethic, including fair distribution of assets and benefits,
development of business systems that respect the requirements of nature, family
needs, personal values and goals, and sustainability. To be considered
sustainable, our businesses must be economically sound, socially acceptable,
and environmentally benign. Each company should set a required amount of hours
to be worked. Any work beyond this should be voluntary, and the employee paid
for the time in accordance with all applicable laws.
We
offer this as a philosophical statement, rather than a mandate. Business owners
must be free to define honest and ethical social conduct within their own
personal beliefs and conditions. In any case, all federal, state, and local
laws must be complied with.
Employees
Employees
involved in organic land care must receive compensation which meets their basic
needs and allows fair return and satisfaction from their work. Included in this
compensation is a safe, respectful, working environment that ensures their
basic dignity. Employees are entitled to
at least one day of rest out of every seven. Employees are to be informed in a
timely and thorough manner of their legal rights and the policies of the
company. Employees must be informed of any hazards in the workplace (e.g.,
toxic materials, dangerous equipment), be properly trained, provided all
necessary personal safety equipment and be instructed in its use, and be well
protected from such hazards. Employees are to be allowed sufficient and
adequate breaks for rest, intake of food and water, and use of sanitary
facilities.
Employers
Employers
are entitled to an honest day’s work from their employees, adherence to all
agreed-upon company policies, as well as reasonable care of company property
and respect for clients and vendors.
Employers are encouraged to go beyond the minimal employer-employee
relationship by increasing participation and responsibility of employees in the
business, with wages and benefits commensurate with such increased
responsibility. Employers are entitled to fair and equitable treatment and
pricing from vendors, as well as acceptable terms of payment, and to be treated
with respect and compensated in a timely manner by their clients.
Clients
Clients
of the company are entitled to honest and ethical business practices, a fair
price for materials and services provided, and a job performed to their fair, reasonable
satisfaction.
Vendors
Vendors
of the company are entitled to honest and ethical business practices and to
compensation within the terms agreed upon with the company.
Care
We must consider the
wider social and ecological impacts of the materials and techniques used and
the landscapes created.
Do No Harm
Every land use
decision we make will have a positive or negative effect on the land in our
care. One of the tenets of organic land care
is to protect and enhance the natural elements that exist on a site—to do no
harm. Elements that benefit the whole ecosystem––such as indigenous plants and
soils, wildlife corridors and habitat, riparian buffers and watershed drainage,
and their interaction with each other and their surroundings––should be carefully
considered before any site “improvements” are made. If these natural elements
are damaged or nonexistent, then restoration or establishment should be the
aim. This can be best done by studying natural areas or remnant woods with
similar landforms that are close by and using this ecology as a model for
restoration.
Genetically Engineered Organisms
In recent years, the organic community
has had to address the use of genetically engineered organisms and their
products in light of the principles and goals listed above. The National
Organic Standards of the United States Department of Agriculture contain the
category “excluded methods” for organic growing, and they describe and define
“excluded methods” as: “A variety of
methods used to genetically modify organisms or influence their growth and
development by means that are not possible under natural conditions or
processes and are not considered compatible with organic production. Such
methods include cell fusion, microencapsulation and macroencapsulation, and
recombinant DNA technology (including gene deletion, gene doubling, introducing
a foreign gene, and changing the position of genes when achieved by recombinant
DNA technology). Such methods do not include the use of traditional breeding,
conjugation, fermentation, hybridization, in-vitro fertilization, or tissue
culture.”
The Standards and the NOFA Accreditation Program
Purpose
of Standards
The
purpose of the Standards is to:
·
Present
the fundamentals of organic land care and currently accepted practices and
materials
·
Specify
the requirements for accreditation for organic land care
·
Specify
practices that accredited land care professionals will pledge to abide by in
providing organic land care services
The
intent of the Standards is not to provide all the information
needed for successful organic land care. More detailed information on organic
land care is provided in the NOFA Accreditation Course in Organic Land Care,
currently offered annually in
Definition
of Terms in the Standards
Preferred
These
are the practices and materials the NOFA Organic Land Care Committee finds to
be ecologically appropriate and in accord with the goals of organic land care.
Allowed
These
are practices and materials that are acceptable when needed, but should be
reduced in favor of the preferred alternatives, where possible.
Prohibited
These
materials and practices are not acceptable in organic land care.
Emergency
Non-Organic Rescue Treatment
There
may be rare occasions when the organic land care professional and the client,
who have previously agreed on organic land care, will decide to use
extraordinary measures that are prohibited under the Standards.
An
example might be to save the life of a tree of great value from a pest that
cannot be adequately controlled using organic methods. In this case, the professional should inform
the client prior to any emergency non-organic rescue treatment about the need
for this treatment. Emergency non-organic rescue treatments should be rare and
only undertaken as a last resort and should be approved by the client.
Standards
Review and Revision Procedures
The
Standards for Organic Land Care were researched and written in
2000-2001 by a group of practicing land care professionals, scientists and
concerned citizens, with assistance from technical advisors. The Standards––and especially the
preferred/allowed/prohibited practices and materials––are intended to be
reviewed periodically by practitioners and the NOFA Organic Land Care Committee
and amended as appropriate. The current
revision is the fourth revision of the Standards.
Suggestions
for changes to these Standards are
welcome. Land care professionals,
scientists, extension educators, government officials and others are invited to
submit suggestions in writing to the Organic Land Care Committee. New materials, new products on the market and
new information on practices will be considered at the time of Standards revision.
OLC
Standards and the National Organic Program (NOP)
The
Standards came originally from the CT and Mass NOFA agricultural
standards, and were developed before the NOP was in effect. On some
issues the Standards have been modified to come closer to
the NOP (notably composting manures), but on other issues we have chosen to
differ. In some ways we are more lenient, and in some ways we are stricter.
Some
specific differences:
·
CT
NOFA agricultural standards did not allow use of Chilean nitrate fertilizer,
and we kept this prohibition in the Standards. The NOP allows use of Chilean
nitrate up to a certain percentage of the nitrogen applied.
·
Inerts
in pesticides: The NOP allows only inert ingredients from EPA Lists 4A
and 4B. A significant problem—and this is also a problem for agricultural
certifiers— is that inert ingredients are proprietary information. So,
they are not on the label, and the manufacturers of the products are not
required to divulge this information. In some cases, manufacturers decide they want to put their
products on the OMRI list, so they reveal their proprietary information to OMRI
and pay OMRI to review this information and put them on the list if
appropriate. Also, manufacturers sometimes choose to reformulate
pesticides to meet the NOP standards and be listed by OMRI (EntrustÒ, a spinosad product formulated for the
NOP and listed by OMRI, is an example). This is expensive, and they don't
generally do this for products labeled for landscape use (such as ConserveÒ, a spinosad product not listed by
OMRI). Therefore, for practical reasons, the Standards currently prohibit EPA List 1 Inerts
(Inert Ingredients of Toxological Concern), which would be required to be on
the label.
·
Emergency
Non-Organic Rescue Treatment: There is no such provision in the NOP.
Accreditation
by NOFA to Provide Organic Land Care
The
NOFA Organic Land Care Program employs an Accreditation Manager who is free
from conflicts of interest with the land care professionals. Accreditation will be granted to an
individual professional upon completion of the designated course, successful
completion of the course examination, and a signed agreement to provide land
care according to the Standards for all clients requesting organic
land care.
Accreditation
will be for a period of one year and is renewable annually. Annual re-accreditation will be granted based
on continued demonstration of competence in organic land care management and
participation in educational programs reviewed and approved for credit by the
Organic Land Care Committee.
Accreditation
Requirements
The
Organic Land Care Committee, overseen by the Boards of Directors of Connecticut
and Massachusetts NOFA, determines the qualifications and rules for enrollment
as an Accredited Organic Land Care Professional. Those who meet the following criteria are
eligible to apply for NOFA Organic Land Care Accreditation:
·
Completed
Application Form and Accreditation Fee
·
Completion
of the NOFA Course in Organic Land Care
·
Demonstration
of knowledge of and skills in organic land care by satisfactory completion with
a passing grade of the Accreditation Examination
·
Signed
pledge of agreement to follow the tenets set out in the Standards
for Organic Land Care
for all clients requesting organic land care
Accreditation
is a privilege granted by the NOFA Organic Land Care Program. If the
Accreditation Manager determines that any land care professional has misled
clients about organic practices or failed to adhere to the Standards in providing services to clients requesting organic land
care, the privilege may be withdrawn.
Public Information
The
Accreditation Manager will provide a list of Accredited Organic Land Care Professionals to the public (currently published in
the NOFA Guide to Organic Land Care)
and also post it on the NOFA Organic Land Care website. The purpose of this
list is to identify trained and qualified professionals, to foster and maintain
professional competency, and to protect the public interest in the area of
responsible use of land care products and land resources. Although persons on
this list of
Accredited Land Care Professionals meet specific requirements, NOFA is not responsible for
quality or costs involved in work performance.
Accredited
Organic Land Care Professionals are allowed to use a NOFA-approved logo on
their printed marketing materials for the year in which they are accredited.
For example, the logo might appear on business cards, brochures, yellow pages
and newspaper advertisements, uniforms and vehicle signage.
The
NOFA Organic Land Care Program has several methods of outreach to publicize the
program and promote the Accredited Organic Land Care Professionals. We publish
educational materials for homeowners and other clients available for the
Accredited Organic Land Care Professionals to distribute.
In
cases where the same business offers organic and non-organic land care options
it is crucial that clients understand clearly whether they are receiving
organic or conventional land care services. Printed business materials and
advertising that are directed to the public must clearly distinguish the
different arms of the business. The
NOFA logo must not be displayed on vehicles providing non-organic treatments.
Any
application equipment used for organic treatments must not also be used for
non-organic treatments. Any materials used in organic land care practices must
be stored with adequate separation from non-organic materials to prevent
cross-contamination.
Site Analysis, Design and Management
Site Analysis, using the principles of
these Standards as a guideline, is the observation of the key elements of a
site, and an understanding of how these elements affect the relationship
between organisms (people, plants, animals, soils) and the site. Site Analysis is the primary discipline used
to determine appropriate land use - including plant selection and placement,
construction and placement of hardscape elements on the site, and in some
cases, site modification to create certain ecosystems.
Design is the creative application of
these principles on the landscape. It
employs the disciplines of ecology and sustainability to create landscapes that
can be managed organically.
Management refers to the holistic care
of landscapes before, during and after installation. It utilizes recognized organic methods and
materials, as well as innovation and experimentation within the guidelines of
these Standards. One of the goals of
organic management is the gradual decrease of inputs as the landscape grows
toward sustainability.
Preferred
·Site analysis that includes: special attention to variation
in microclimates; evaluation of sunlight availability and degrees of shade;
soil analysis (see Soil Testing); wind patterns and air circulation;
temperature; conditions of existing plants; and moisture characteristics of the
site
·Selecting and placing plants whose characteristics are
appropriate to the site
·Leaving established ecosystems intact (except where invasive
or harmful plants exist—see Invasive Plants section)
·Selecting and using native plants correctly
·Producing food (vegetable gardens, edible landscapes)
·Creating, restoring, protecting, and enhancing wildlife
habitat (e.g. riparian buffers)
·Establishing buffers to protect organic sites from
neighboring non-organic sites
·Designing landscapes that are designed to enhance the
principles of ecology and sustainability (e.g. lawn reduction)
Allowed
·
Modifying
existing habitats within the guidelines of these Standards where new landscape
design is desired
Prohibited
·
Breaking
local, state or federal laws regarding wetlands and buffer zones
·
Using plants inappropriate to the site,
or that require extraordinary inputs and efforts to keep them alive
·
Modifying a site in a way that results
in considerable harm to the environment
Air
Overview
By
increasing plant biomass and soil organic matter, more carbon is stored
on-site, which reduces greenhouse gas effects on the earth’s atmosphere. The production and use of synthetic
fertilizer, particularly nitrogen, significantly contributes to greenhouse
gases. This is an important reason to
use natural materials as fertilizers.
Proper
choice and placement of plants may improve quality of life and reduce impact on
the environment, including such conditions as dust, pollutant drift, snow
drift, temperature modification, air flow and visual impacts.
Air
is an essential component of soil and is a requirement for healthy root
growth. A typical landscape soil
contains 5% humus, 45% mineral, 25% air, and 25% water. This soil is easy to
grow plants in, holds moisture, minimizes erosion and provides air to aerobic microorganisms
and roots of plants. There are other soil types that contain more or less air
that are perfectly natural and should be left in their natural state.
Preferred
·
Create
buffers (or put up fencing) to protect the property from spray, drift, dust and
other airborne pollutants
·
Utilize
aerobic compost properly on site (to minimize air pollution from transporting
materials to and from the site)
·
Choose
and place plants to moderate temperature and influence airflow
·
Use
methods that maintain adequate soil organic matter and natural soil porosity,
and reduce soil compaction
Allowed
·
Mechanical
aeration and breakdown of cores
·
Application
of organic matter or sand
·
Soil
cultivation
·
Irrigation
(only when necessary)
·
Limited
use of leaf blowers and other power equipment that cause air and noise
pollution
·
Appropriate
use of heavy equipment
·
Approved
soil amendments properly applied
·
Organic
soil flocculent
Prohibited
·
Over-application
of soil amendments that may cause soil compaction and/or air pollution
·
Over-watering
that may block or reduce aeration of the soil
·
Excessive
mechanical aeration or rototilling and resultant oxidation of organic matter
and soil compaction
·
Any
non-approved soil amendments
Water
Overview
Water is an essential, non-renewable
component of the environment and moves through the environment continuously in
a process known as the water cycle. Under
natural conditions, some rainwater soaks into the soil and is then taken up by
plants or moves deeper into the groundwater system and some flows overland as
runoff. Adding impervious surfaces
increases water runoff and decreases infiltration. When the land surface is changed-- through
soil compaction, loss of vegetative cover or building of structures and paving
of roads and parking areas--impermeable surfaces increase. Rainwater can no
longer soak into the ground and instead runs over the surface to the nearest
down-slope water body, creating flooding problems.
Water
conservation and protection of water quality should be factored into site
design and management practices.
Existing natural water features (wetlands, streams, ponds) on and near
the property should be identified and protected. Where appropriate, excessive
rainwater runoff should be minimized by promoting infiltration with rain gardens
or other rainwater collection techniques. Soil texture (sand/silt/clay) as it
affects water-holding capacity and depth to groundwater (which fluctuates
seasonally based on rainfall and plant uptake) are important factors in plant
selection.
Preferred
·
Right
plant, right place—choose plants suited to site conditions
·
Minimize
impermeable areas (driveways, terraces, etc.)
·
Minimize
lawn areas (to reduce irrigation needs)
·
Direct runoff to natural depressions or
infiltration areas
·
Create/maintain natural buffers along
watercourses and wetlands
·
Rainwater collection properly
maintained to prevent mosquito breeding and contamination
·
Provide appropriate water sources for
wildlife
·
Rain gardens
·
Use mulches and plants to retain
moisture
·
Choose
plants that minimize the need for irrigation, pest and disease control
·
Maintain
existing soil structure
Allowed
·
Irrigation
only when necessary based on soil type and plant needs
·
Retention
basins designed by a professional engineer that meet all applicable laws
·
Drainage
of non-wetland areas where regulations permit, providing the outflow causes no
damage to the surrounding environment
·
Use
of gray water for irrigation of non-edible plants
·
Improve
soil structure to reduce compaction and erosion
Prohibited
·
Excessive
irrigation that may cause water run-off, puddles, compaction, disease or growth
of slime mold in lawns
·
Inappropriate
plant choice—avoid plants that are not suited to site conditions
·
Surface
water causing flooding or erosion problems
·
Leaching
of nutrients and/or soil amendments through runoff
·
Drainage
or filling of wetland areas
Soil Health
Overview
A
basic principle of any organic land care practice is knowledge of and proper
care for the soil. Organic land care emphasizes a holistic approach to plant
health by nourishing the soil life instead of feeding the plant directly. This
results in healthy soil, which produces healthy plants. The relationship
between a given soil and a plant can be looked at in two ways:
1) the need to alter the soil can be minimized by choosing
appropriate plants for that soil
type; and
2) the soil can be amended to provide for the
long-term health of the plant.
In
either case, soil testing is important in order to understand the
characteristics of the soil and the balance of soil elements (see Soil
Testing). Soil tests along with site analysis allow the land care professional
to select and implement practices that maintain or improve the soil’s life and
vitality and minimize soil erosion. A healthy soil is free of crusts, compaction,
pesticides and other toxins, salt buildup, and excessive erosion. In a healthy
soil, the native organisms are active because organic matter is sufficient and
nutrients are balanced.
The
soil food web is the community of organisms living in the soil. A healthy soil food web forms protective
layers around roots to prevent pathogens from attacking the roots; helps plants
obtain nutrients from the soil; breaks down toxic compounds that inhibit plant
growth; improves disease suppression; and builds soil structure so that
nutrients and water are easy for the plant to obtain, and easy for roots to
move through. For more information about
the soil food web, see the Soil Foodweb web site www.soilfoodweb.com.
In
natural systems, organic matter generally cycles in place, added to the soil
through root and stem decay of winter-killed annuals and leaf decay. A thriving
microbial community digests and breaks down this organic matter to release
nutrients back to the soil. The organically maintained landscape retains and
recycles organic matter, to the extent that the client’s needs and the
situation will permit. On-site composting is a means to this end, as is direct
mulching. By closing the nutrient cycle in this way, the need for external
inputs is minimized.
Organic
soil amendments may be needed to help balance a soil’s chemistry, stimulate its
biology, and restore its physical composition. Such amendments may also be
needed to feed turfgrass in a lawn, which has extraordinary nutrient needs
because it is grown in an unnatural way––perpetually mowed and kept green as
long as possible.
Organic
soil fertility is based on feeding the soil, not just the plant. This means that carbon is fed to the soil
along with nitrogen through the use of manure, compost, blended organic
fertilizers, and, in some situations, cover crops. Horticultural methods which short-cut this
natural order by directly feeding plants synthetic
nitrogen-phosphorus-potassium (NPK) lead to damaged soil and a weak root
systems, making the plants more susceptible to insects, disease, and drought.
Over-fertilizing the plant (chemically or organically) may also inhibit the
development of mycorrhizae—symbiotic fungi growing on or around plant roots
that help to gather nutrients beyond the range of the roots themselves.
Eventually the soil structure collapses and it becomes infertile. To revive
dead, compacted soil, it may be necessary to apply compost to improve and build
soil life.
A
well-balanced soil-building program that increases humus content and organic
matter gives many benefits. It recycles nutrients, improves water retention,
balances minerals, and buffers pH. In addition to compost and manure, other
amendments may be indicated based on the soil test results, such as root stimulants,
rock dust, secondary micronutrients, flocculents, beneficial microbes, organic
humus, volcanic humic shale ore, fulvic acid, or kelp.
Most
turf grasses and ornamentals perform best when certain cations are in balance,
with the base saturation in these ranges: potassium 2-7%; calcium 65-85%;
magnesium 10-20%; hydrogen 0-5%; sodium 0-5%. Micronutrient needs may differ
according to the turf or ornamental plant type. It is important to get the pH
in the right range (depending on whether the plants to be grown prefer acid or
nearly neutral soil). According to one school of thought, it is important to
balance the calcium-to-magnesium ratio.
If magnesium is too high relative to calcium and liming is needed to
adjust pH, use calcitic lime instead of dolomitic lime, which is high in
magnesium.
Soil
Testing
Overview
Healthy
soil contains the proper balance of organisms, minerals, nutrients, organic
matter, and other essential components––information that can be determined by
soil testing. Soil sampling is used to determine depth, structure and texture
of the topsoil layer and basic characteristics of the subsoil layer. A standard
soil test is used to determine soil pH (acidity/alkalinity); the percent of
organic matter contained in the soil; any nutrient or mineral deficiencies, excesses
or imbalances; and recommendations for corrective measures. For these reasons
soil testing is mandatory when amending the soil with nitrogen, phosphorus or
potassium. A more comprehensive soil
bioassay can evaluate the presence and balance of soil organisms such as fungi,
bacteria, nematodes and protozoa.
A
soil test will produce meaningful results only when a representative, aggregate
sample is collected and properly prepared for each area of interest (the
vegetable garden, the lawn, the perennial bed, around a tree, etc.). Obtain soil samples (generally to a depth of
4-6”) using a clean plastic or stainless steel tool and collect multiple
samples (1-2 per 100 ft2).
Mix them in a plastic or stainless container and remove all plant
material and rocks using a sieve in the range of 2 mm (0.79”). Retain a portion (~1 oz.) of the aggregate
sample; store at ambient temperature, out of direct sunlight, preferably in a
porous container. Submit the soil for
testing in a timely manner; an overly aged sample may no longer be
representative.
Soil test kits sold in
garden shops are frequently based on colorimetric reactions and their results
are only as accurate as one’s visual acuity.
Homeowner-grade pH meters are also highly suspect in that their readout
is analog and calibration against standard buffer solutions is not
possible. Recently introduced digital pH meters such as the Hanna
pHep5 are capable of two-point calibrations against standard buffer
solutions. In the hands of a trained
soil tester, their readings are both accurate and precise. Soil pH is measured by preparing a slurry of
the sample in distilled or deionized water, swirling the suspension for a
minute or more, then placing the meter in the liquefied soil sample until a
stable reading is obtained.
Preferred
·
Perform
an initial soil test, then test every three years afterward, according to
standard procedures
·
Obtain
separate soil samples from each type of microclimate (sun/shade, wet/dry, etc.)
to ensure accurate representation of all soil conditions on the site
·
Send
samples to a professional or government soil testing lab for analysis and
organic recommendations and soil bioassay if desired (see Appendix for a list
of soil testing laboratories)
·
Keep
records for each site, including name and location, date of initial test,
preexisting conditions and any observations, and a copy of the soil test
results
·
Site
records should include all soil test results, a record of any applications and
a summary of any changes observed
Allowed
·
In
cases where the soil test laboratory recommends non-organic amendments, adjust
to meet the requirements of these Standards
·
Application
of amendments after planting, following soil test results
·
Measurement
of soil pH using a digital pH meter calibrated against standard buffer
solutions. Individuals performing such
tests should be trained in the appropriate collection of soil samples,
calibration and use of the meter, as well as the standard testing protocol.
Prohibited
·
Using
a home soil test or kit to determine application of soil amendments
·
Using
tools and containers for soil testing that retain remnants of other matter that
would taint the results
·
Amending
the soil with nitrogen, phosphorus or potassium without the guidance of proper
soil test results
·
Following
soil test recommendations for amendments and practices that do not meet these
Standards
·
Using
a colorimetric soil test kit or homeowner-grade (analog) pH meter to determine
application of soil amendments.
Toxic
Elemental Species in Soil
Overview
Many
elemental species (metals, metalloids, and non-metals) occur naturally in soil
as inorganic ions (charged species) and at least 18 are considered to be plant
nutrients. Of these elements,
approximately half are required by plants in very small quantities and are
described as trace- or micro-nutrients.
Human activity can adversely affect soil, either by the incorporation of
toxic elements like mercury, lead, and cadmium or by increasing the proportion
of necessary trace elements like copper or zinc to toxic levels. Modes of incorporation into soil can include
the use of synthetic pesticides, pressure-treated wood, past use of
lead-containing paint, application of industrial or domestic sludge (sewage
sludge and biosolids), smokestack emissions, and past use of leaded fuels. An advanced soil test is strongly
encouraged in potentially contaminated sites before growing food or creating
play areas for children.
Toxic
elements, once introduced to the soil, have a tendency to persist. Preventing
the contamination of soils is critical because remediation of polluted soil can
be both cost-prohibitive and time-consuming.
The following management practices will not remove toxic elemental
species, but will help to decrease their solubility, thereby reducing their
bio-availability and the potential for adverse effects. Metallic elements such as mercury, cadmium,
lead, nickel, copper, zinc, chromium, and manganese exist as positively charged
species (cations). Molybdenum is also a
metallic element, but is found in a negatively charged form (an anionic
species) as are metalloids and non-metals like arsenic, selenium, and
boron. Some elements, especially arsenic
and chromium, exist in multiple forms or oxidation states. Chromium in the +3 form (Cr+3) is
a plant micro-nutrient. In its
fully-oxidized form (Cr+6), this element (especially at high levels)
is associated with cancer and birth defects.
Proper management of elemental contaminants begins with an advanced soil
test. Once the results are known and
fully understood, the proposed remediation plan must comply with all pertinent
federal, state, and local statutes.
Preferred
·
Raise soil pH to
6.5 or above (but no higher than 7.2) to reduce the solubility/bio-availability
of cationic contaminants such as lead and cadmium (or when other cationic
elements like copper, zinc, or manganese are present at excessive levels).
·
Lower soil pH to
reduce the solubility/bio-availability of anionic elemental species such as
boron, molybdenum, and selenium when they are present at excessive levels.
·
Where
ecologically and legally feasible, drain wet soils to decrease the
bio-availability of elemental contaminants (except Cr+6)
·
Remediate soil
contaminated with Cr+6 by increasing application of both organic
matter and water (reduction to the less-toxic Cr+3 form occurs when
soil oxygen levels are low).
·
Apply an allowed
form of phosphorous (see Fertilizers and Soil Amendments) to reduce the
solubility of cationic contaminants- but note that the effect will be exactly
the opposite on anionic contaminants [extreme care should be used when applying
phosphorous because (in excess) it will cause water pollution].
·
Limit soil
disturbance to reduce human exposure at suspected or known to be contaminated
sites (heavily-traveled roads, near gas stations, and industrial areas).
·
Maintain a thick
turf, dense evergreen groundcover, or impenetrable vegetation on contaminated
sites to prevent children from digging and to reduce tracking of contaminated
soil into buildings.
·
Work in
collaboration with a phytoremediation specialist to determine how to use
specific plants to bio-accumulate and remove toxic elemental species from the
contaminated site.
Allowed
·
Disturbance
of contaminated sites, provided no edible and/or berrying plants are installed,
and there is no migration of contaminants to adjacent sites
·
Cover
contaminated soil with sod or with plastic and mulch, gravel, or stone
·
When
planting over the surface of a contaminated site, first seal the site with
plastic mulch, then add an appropriate amount of compost or soil for the plant
Prohibited
·
Installation
of edible and/or berrying plants
·
Removal
of contaminated soils for other uses, except for regulated disposal
·
Runoff
from disturbed sites onto other areas
Materials
in Contact with Soil or Plants
Overview
Materials
that come in contact with soil or plants, such as building materials, masonry,
edging materials, and landscape fabrics, should be free of harmful substances
such as toxic metals, pesticides, or toxic chemicals. Pressure-treated wood
products which contain chromated copper arsenate (CCA) are of special concern.
These products are no longer sold, but if they have been used in the past,
toxic residues may still be present.
Studies have shown that high amounts of CCA, which is highly toxic, can
be released from the wood in most soils of the northeast.
Preferred
·
Untreated rot-resistant wood, such as
cedar, white oak, or black locust from sustainably harvested sources
·
Wood alternatives such as recycled
plastic and plastic and wood fiber composites
·
Masonry (stone, bricks, etc.)
·
Non-galvanized or stainless steel
·
If pressure treated wood is present,
the soil should be tested for arsenic, chromium, and copper, before planting
food crops or soil disturbance
Allowed
·
If
chemically treated wood already exists on a site and cannot be removed or
client is unwilling to remove it, then wood can be coated with paints or stains
formulated for such use, such as polyurethane, acrylic and spar varnish.
Re-coat as required.
·
Newspaper
without glossy or color inks
·
Plastic
and nonwoven geotextile fabrics which do not contain polyvinyl chloride (PVC)
·
Synthetic
burlaps if removed completely at time of planting
Prohibited
·
All
types of chemically treated wood, burlap, stakes or twine
·
Chemically
treated paper and cellulose mulches
·
Newspaper
with glossy papers or color inks
·
Plastic
and nonwoven geotextile fabrics that contain polyvinyl chloride (PVC)
·
Synthetic
burlaps
·
Creosote-
or tar-treated wood (such as railroad ties)
·
Petroleum-based
wound dressings
·
Galvanized
steel
Fertilizers and Soil Amendments
Overview
Fertilizers
and soil amendments are tools that enable us to modify existing soil
conditions. The “feed the soil” principle is used to benefit plant health, not
artificially stimulate plant growth. Unnecessary applications of any fertilizer
or soil amendment can cause mineral nutrients to build up to excessive levels
in the soil. At these levels, nutrients may enter local water resources.
Nitrogen and phosphorus are the nutrients most involved in eutrophication of
water bodies, and are thus of major concern as pollutants. Nitrogen can also be
a health hazard when it pollutes drinking water supplies.
Many
potential nutrients in soils are not readily available to plants. Proper
management of soils can free these nutrients for uptake. The rate of release of
mineral elements depends on environmental factors specific to each site.
Therefore, the use of any amendment must reflect soil test results and good
stewardship of the environment. It is preferred to use renewable materials that
are sustainably produced. Many nutrient
amendments are mined or harvested from natural sources that are not renewable.
We do not want to waste these resources for our short-term benefit.
·
Compost in the amounts specified
below
·
Compost teas
·
Cover crops and green manures
·
Local or on-site nutrient sources
·
Blended
organic fertilizers with ingredients that meet these Standards
·
Exceeding the amounts of macronutrients recommended by a soil test
·
Synthetically derived ingredients
·
Blended
fertilizers using a mixture of organic and synthetic materials, including
transitional products
·
Sewage sludge
·
Allowing
fertilizers to remain on sidewalks or pavement (typically after being applied
by rotary spreaders). Fertilizers left on pavement go directly into the storm
sewers and then into waterways. Any spillage should be swept or vacuumed up and
reused.
Compost
Compost
has many advantages over topsoil or mulch alone. Incorporating compost improves
turf, shrub and shade tree performance in marginal or poor soils. Good quality
compost improves soil structure, reduces runoff and compaction, enhances
biodiversity, increases water and nutrient retention, increases microbial
activity, supplies nutrients, helps suppress and prevent plant diseases, detoxifies
certain pesticides, and inactivates and kills potential human pathogens. The
benefits to the plants are: improved establishment of turf, ornamentals and
shade trees; improved color; increased root growth; and reduced need for
fertilizer, pesticides, and irrigation.
Compared
with fertilizers, compost generally contains low and variable amounts of
nutrients. A small amount of nitrogen (ammonium) is present in some compost.
Other organic fertilizers may be required to meet plant nutrient requirements. Composting
involves the decomposition and stabilization of raw, clean organic waste to an
end-product of a humus-like material. High quality compost is organic material
that has been well-decomposed, and is highly aerobic as a result of regular
aeration. It is high in beneficial soil organisms such as actinobacteria,
fungi, nitrogen-fixing bacteria, aerobic bacteria and many others.
A
commonly accepted recipe for compost is to use 3 parts by volume brown material
(carbonaceous, such as wood chips, sawdust, leaves, or shredded paper) and 1
part green material (nitrogenous, such as grass clippings, kitchen waste, green
plant material, or manure).
Characteristics
of well-decomposed or finished compost
Appearance:
Few recognizable
components of the initial raw materials. Color resembles dark topsoil, and
compost has a light, crumbly structure. Finished compost does not release steam
when disturbed.
Odor:
An “earthy aroma”
with no offensive odors such as ethanol, ammonia or sulfur.
Temperature:
Not hot to the touch.
Weed
seeds: No
weeds growing in or around the pile. Proper composting at high temperatures
destroys viable weed seeds.
Moisture
content: Between
30-50%. Above 60%, compost tends to clump and not spread evenly, is heavy and
difficult to handle, and can be anaerobic. Below 20%, it produces excessive
dust, will tend to wash away and favors excessive growth of actinobacteria.
Carbon-to-nitrogen
(C:N) ratio: Approximately
15:1, from raw materials with an initial C:N ratio of between 25:1 and 40:1.
Above 30:1, soil microorganisms can immobilize nitrogen, making it unavailable
to plants.
pH:
Finished compost exhibits a pH
between 6 and 7, normally around pH 6.8, a range which is favorable for most plants. Extremes in pH
may result in reduced availability of some plant nutrients and/or toxicity
problems.
Additional
methods of evaluating compost quality: Laboratory testing and recommendations from other land care
professionals. Commercial composters
should have state certification or permit, as appropriate. A simple test to determine if compost is
mature is to put 3 cups of compost in a sealed plastic bag and let it sit
overnight at room temperature. If the
bag expands, the compost is not finished.
Another test is to use the compost to germinate watercress (Nasturtium officinale) seeds.
If the seeds fail to germinate, or the seedlings are weak, spindly, or
distorted, then the compost is not finished. (Note that watercress is listed as
potentially invasive and should not be planted in the field.) Red clover (Trifolium pratense)
is the best indicator of herbicide contamination. Garden cress (Lepidium sativum)
is a good indicator plant for compost maturity.
Improperly composted organic matter
that has gone anaerobic (or putrefied) may contain compounds toxic to plants
and may have offensive odors from production of ethanol, ammonia or hydrogen
sulfides. Check with your compost
supplier for evidence of proper quality control to avoid this problem. Under specific conditions, anaerobic compost
may be used to create proper growing media for wetland plants.
Caution: Herbicide Contamination of Compost
In the past, organic farmers and land care professionals have not had to be too concerned about herbicide residues in compost because most herbicides break down rapidly in the composting process. However, the persistent herbicides, clopyralid and picloram, which break down very slowly in composting, have been found to contaminate compost to the point where sensitive plants were damaged. As a result of these problems, the primary clopyralid product, “Confront”, is no longer registered for use on residential lawns. However, it is still labeled for use on commercial lawns and golf courses. Herbicides containing clopyralid and the similar compound picloram also continue to be used agriculturally, including for cereals, hay and pasture. They pass quickly through grazing animals and pass into the urine, so compost made from feedstocks, including animal bedding and waste, may also be contaminated. See articles: www.mindfully.org/Pesticide/Clopyralid-Composting-Dow.htm and www.puyallup.wsu.edu/soilmgmt/Clopyralid.htm.
Be
aware of these hazards, discuss them with your compost suppliers, and ask them
if they have conducted bioassays on any potentially contaminated materials. For
more information, see the magazine BioCycle.
Review articles are posted on their website at: www.jgpress.com/BCArticles/2001/070132.html.
Analytical techniques
associated with herbicide and pesticide residues continue to evolve as does our
understanding of their degradation pathways.
Once in the environment, herbicides are chemically and/or biologically
transformed into new chemical entities that no longer kill weeds. However, these breakdown products should not
automatically be considered biologically benign. 2,4-dichloro-phenoxyacetic acid (2,4-D)
cleaves to produce 2,4-dichlorophenol as its initial degradation product; this
halogenated aromatic compound is significantly
more toxic than the parent herbicide.
When in doubt about the inclusion of potentially contaminated organic
raw materials into a mix for composting, consider not only the actual herbicide
or pesticide, but also its known or proposed degradation products as well.
Preferred
·
Compost
yard waste properly on-site, and use the compost in beds or gardens. Locate
compost piles where they will not be susceptible to runoff
·
Monitor
soil phosphorus levels with soil tests so that repeated compost application
does not result in build up of excess phosphorus over time (see Phosphorus
section)
·
Use
compost that is well decomposed
·
Use
compost from local sources using local materials to reduce transport of bulk
materials
·
Soil incorporation prior to planting
(one time application):
Where soil improvement is needed, compost may be applied to the soil surface as
a 1-2 inch layer (approximately 3-6 cubic yards per 1,000 sq. ft.), then
incorporated into the soil to a depth of 4-6 inches. Make sure compost is
thoroughly mixed with soil. A two-inch layer is better suited for very sandy or
low-organic-matter soils. For more fertile soils, use less.
·
Top Dressing/Surface Application
-
On
turf: 1/4 inch or less, no more than two times per year for no more than three
years unless a soil test shows organic matter less than 4% and phosphorus below
“medium”
-
Around
perennials: 2 inches or less
-
Around
ornamentals and shade trees: 3 inches or less
·
Radial trenching or Vertical mulching:
For alleviation of compaction around woody plants, mix equal parts of
compost and excavated soil to backfill trenches around the plant
Allowed
·
Any
compost which appears adequately decomposed, does not contain sewage sludge,
industrial toxic wastes, large stones, trash or other prohibited materials, and
is made from at least two different raw materials
·
Sheet
composting (surface application of organic material to compost in place) in
establishing gardens and beds. Note restrictions below on sheet composting
manure in beds where human food crops will be grown.
·
Anaerobic
compost only for growing wetland plants or restoring wetland soils
Prohibited
·
Sewage
sludge (biosolids), municipal solid waste, paper mill by-products as raw
materials of compost. Current EPA
standards are not adequate to protect the public from contamination of
biosolids from toxic elemental species, industrial toxins, pharmaceuticals, and
radioactive materials. These materials may be contaminated by toxic elemental
species and other industrial toxins.
·
Compost
with excessive amounts of plastic, undesirable objects or offensive odors
·
Compost
with large amounts of weed seed
·
Planting
human food crops in sheet composting systems that use animal manure within 120
days before harvest (for other restrictions on use of animal manure, see the
Manure section)
·
Using
more than the amounts specified
·
Over-application
of compost, which results in exceeding the limits for nitrogen and/or
phosphorus (see sections under Fertilizers and Soil Amendments)
·
Anaerobic
compost as a soil amendment
Compost
Tea
Compost
tea is attracting increasing attention as an inoculant to enhance or restore
soil and leaf surface microflora. There is research to show that compost
tea has a role in deterring disease.
However, under current laws, it cannot be claimed that compost tea
suppresses or controls disease because it is not registered as a pesticide by
the U.S. Environmental Protection Agency.
Although compost tea is sometimes made by simply fermenting compost in
water, it is now more commonly made in a brewer or extractor, which
creates aerobic conditions to yield great quantities of bacteria, yeasts and
fungi. In many cases a range of organic adjuvants including worm
castings, kelp and/or fish hydrolysate are added as food sources; and yucca
extract, saponin, rock dust, humic acid and/or fulvic acid are added as
catalysts to create teas for specific uses.
To maintain high quality, compost tea must be constantly aerated.
According
to Soil Foodweb, Inc. perennials, annuals, and turf require
a compost tea made from compost balanced between fungi and bacteria, or
slightly higher in bacteria. This can be created with an initial mixture of 25%
animal manure or worm castings (see Manure section for composting
requirements), 50% green material (household waste, leaves and grass
clippings), and 25% woody materials (wood chips, bark, sawdust and mushroom
substrates). Shade trees and shrubs
require a compost tea
made from compost high in fungi. This can be created with an initial mixture of
50% green material, 45% woody materials resistant to rapid decay, and 5% manure
or worm castings.
Compost
tea can be used to adjust soil biology, in order to provide the proper soil
environment for the plants we are trying to grow.
Caution:
There are a lot of variables involved in creating high quality compost
tea; therefore it is important to
understand the process thoroughly before attempting to make or use compost tea.
Preferred
·
Compost tea should be maintained in an aerobic state at all
times.
·
Constituent materials as allowed by these Standards
·
Compost tea should be used within 6 hours of brewing. Extracted tea can be used for a longer
period.
·
The ratio of fungi to bacteria can be adjusted for its intended
use
·
Compost tea should have a level of Escherichia coli of less than 120 colony forming units per 100
milliliters
·
Compost tea can be applied by soil drenching, root dip, or
foliar application to improve lawn/plant health and vigor
Allowed
·
General purpose compost tea, in which the biology has not been
adjusted for a specific use
Prohibited
·
Compost tea made with materials prohibited by these Standards
Manure
Overview
Manure
is animal excrement that may be used as a nutrient amendment. A manure pile
that has not been aerobically composted is considered raw manure. Raw manure is
rarely used directly in land care, because it is difficult to handle and apply
and is highly odiferous. However, manure is processed and mixed with other
materials in blended fertilizers. Manure can contain human pathogens,
pesticides, antibiotics, and growth hormones, therefore it must be completely
composted before surface application. Manure may also contain prions and/or arsenic,
which are not eliminated by composting.
Manure from organic sources should not contain any of these substances. Any manure can contain high amounts of weed
seeds, most of which can be killed by composting at high temperature. Unless
incorporated, into the soil, the
nitrogen in raw manure can volatilize and be lost into the atmosphere or be
leached out by surface water and become a pollutant. Only well-composted manure
should be used within 120 days of harvest on plants being grown for
consumption, or not less than 90 days
prior to the harvest of a plant whose edible portion does not have direct
contact with the soil surface or soil particles.
Allowed
·
Aerobically
compost manure until it has the characteristics of finished, well-decomposed
compost as defined above in order to minimize the risk of survival of human
pathogens
·
If
an in-vessel or aerated static pile system is used, see the National
Organic Standards
for guidelines see: www.ams.usda.gov/nop
·
Fresh
manure, dehydrated manure, and manure slurry may be used only if
soil-incorporated and applied more than 120 days before harvest of any crop for
human consumption
·
The
amount of manure allowed per year should be determined by limits on nitrogen
and phosphorus (see sections under “Fertilizers and Soil Amendments”)
Prohibited
·
Application
of raw manure in fall/winter without actively growing ground cover
·
Raw
manure applied on snow or frozen ground
·
Raw
manure applied on sandy, fast-draining soils in absence of ground cover
·
Raw
manure applied where human contact is probable, even if soil-incorporated
Nitrogen
Overview
Nitrogen
is an essential macronutrient because it is required to create amino acids and
proteins, genetic material, chlorophyll and other important biochemical
molecules. Nitrogen is the most abundant gas in the atmosphere (78%) but the
gaseous form (N2) is inert and unavailable for use by animals and
most plants. Turning N2 into available nitrogen, or “fixing” it,
requires breaking the bond between the nitrogen atoms, which requires energy.
Under natural conditions nitrogen is fixed by lightning strikes through the
atmosphere and by the work of a few species of symbiotic bacteria and some
free-living bacteria and fungi in the soil or water. The amount of new,
naturally “fixed” nitrogen being produced at any time is quite small compared
to the amount already fixed and cycling through the ecosystem.
Human activities have almost doubled
the amount of fixed nitrogen entering the cycle through the industrial
production of fertilizer, selective cultivation of nitrogen-fixing plants and
the burning of fossil fuels. Inorganic fertilizer is manufactured from N2
using an extremely energy intensive process.
See: www.epa.gov/watertrain/nitroabstr.html
These changes have affected the natural
systems by increasing greenhouse gases in the atmosphere, depleting the ozone
layer, increasing acid rain and smog conditions, creating eutrophic
(over-productive) conditions in lakes and estuaries, and changing ecosystem
balances by favoring N-tolerant plants over other species while creating
deficiencies in other nutrients (calcium, potassium and magnesium). Nitrates in
drinking water have also been linked to human health problems.
Plant
and animal nitrogen sources also contain phosphorus, therefore their use should
be limited by the requirements for phosphorus as determined by a soil test.
Preferred
·
Alfalfa
meal
·
Composts
·
Cover
crops and green manures
·
Lawn
clippings
·
Teas
made from approved composts
·
In
lawns, minimize the need for nitrogen by leaving grass clippings, planting
low-maintenance varieties, and including legumes in the lawn mix
·
Feather
meal and other low-phosphorus organic materials
Allowed
·
Blood
meal (take precautions to avoid direct human contact as blood meal may contain
pathogens)
·
Vegetable
meal
·
Fish
hydrolyzate, emulsion or meal (caution, may contain mercury, PCBs or other
contaminants). Be aware when choosing to use fish products that massive
over-fishing is causing severe ecological damage in oceans.
·
No
more than 3 pounds of soluble nitrogen per 1,000 square feet per year
·
No
more than 1 pound of soluble nitrogen per 1,000 square feet per
application
·
Rates
of nitrogen application must be further reduced after 2 years of organic
management
Caution:
the recommended application rate on some formulated fertilizer products will
result in over-application of nitrogen.
For example, if you use corn gluten as an herbicide, that counts as two
applications of nitrogen at 1 pound per 1,000 square feet each. Only one additional application of nitrogen
of 1 pound per 1,000 square feet is allowed per year. This is because the current manufacturers’
recommended application rates for corn gluten as a pre-emergent herbicide
exceed the allowable rates for a single application of nitrogen.
Prohibited
·
Chilean nitrate, which has a high salt
content, is water soluble and has a similar effect on soil as synthetic
nitrogen. This is a place where the OLC Standards differ from the NOP (National Organic
Program). Fertilizer approved under NOP
by OMRI may contain Chilean nitrate
·
Application
of nitrogen fertilizer to lawns when grass is not growing actively enough to
use it rapidly, generally between October 15 and April 1 in
·
Allowing
fertilizers containing nitrogen or phosphorus to remain on sidewalks or
pavement (typically after being applied by rotary spreaders). Fertilizers left
on pavement go directly into the storm sewers and then into waterways. Any
spillage should be swept or vacuumed up and reused.
·
Leather
meal or its by-products
·
Sewage
sludge
·
Synthetically-derived
nitrates, urea, ammonia (e.g. ammonium sulfate)
Phosphorus
Overview
Phosphorus,
in the form of phosphate, is an essential macronutrient—it is a vital part of
the cellular energy transfer, or ATP system.
Phosphorus is added to soils in natural systems by rock weathering.
Leaching and runoff remove phosphorus from the soils, where it is carried to
aquatic systems and gradually settles into deep water sediments in lakes and
oceans. These large “sinks” of
phosphorus can only be returned to the phosphorus cycle by upwelling of deep
waters or geological uplift of marine sedimentary rocks. Because of the long geological time involved
in cycling phosphorus out of “sinks,” retaining phosphorus in terrestrial and
aquatic ecosystem cycles is very important.
Human activities have increased phosphorus inputs to the soil through
the application of phosphorus-rich fertilizers, mined from rock phosphates and
guano. Much of this phosphorus leaches (or washes) from the soil and into aquatic
ecosystems. In fresh-water ponds and lakes, excess phosphorus can substantially
increase plant productivity and lead to eutrophic conditions, causing increased
phytoplankton and bacteria growth, loss of dissolved oxygen and loss of animal
life in the system.
If
a standard soil test gives a rating of medium or above for phosphorus, then no
additional phosphorus should be applied.
If other nutrients are needed, use organic fertilizers or composts that
are low in phosphorus.
Preferred
·
Compost
·
Cover crops and green manures
·
Compare
with fertilizer and soil amendments preferred above
·
Alfalfa
meal
Allowed
·
Rock
phosphates
·
Steamed
or precipitated bone meal (take precautions to avoid direct human contact as
bone meal may contain pathogens
·
Greensand
Prohibited
·
Mono-ammonium
and di-ammonium phosphate
·
Single
and triple super phosphate
·
Other
synthetically-derived phosphates
·
Applying
more phosphorus than is needed based on soil testing
Potassium
Preferred
·
Composts
and compost teas
·
Alfalfa
meal
Allowed
·
Greensand
·
Seaweed
·
Sulfate
of potash (potassium sulfate)
·
Sulfate
of potash, magnesium (such as sul-po-mag)
·
Rock
or quarry dust
·
Clean wood ashes
[not to be co-mixed with ashes resulting from the combustion of painted or
treated wood, wood composites, coal, household trash, or glossy (colored)
paper]
Prohibited
·
Muriate
of potash (potassium chloride)
·
Synthetically-derived
potassium
Calcium
Allowed
·
Aragonite
·
Calcitic
limestone (calcium carbonate)
·
Agricultural
gypsum (calcium sulfate)
·
Kelp
meal
·
Dolomitic
limestone
Prohibited
·
Burned
or quick lime (calcium oxide)
·
Hydrated
or slaked lime
·
Synthetically-derived
calcium
Sulfur
Allowed
·
Sulfur
(elemental)
·
Epsom
salt (magnesium sulfate)
·
Agricultural
gypsum (calcium sulfate)
·
Sulfate
of potash (potassium sulfate)
·
Sulfate
of potash, magnesium (such as Sul-po-mag®)
Prohibited
·
Synthetically-derived
sulfates
·
Ironite® (contains high levels of lead and arsenic)
Magnesium
Allowed
·
Dolomitic
limestone (magnesium carbonate)
·
Epsom
salt (magnesium sulfate)
·
Greensand
·
Sulfate
of potash, magnesium (such as Sul-po-mag®)
Prohibited
·
Burned
or quick lime (magnesium oxide)
·
Synthetically-derived
magnesium
Micronutrient
Sources (Manganese, Zinc, Boron, Copper, Iron, Molybdenum, Chlorine)
Preferred
·
Manage
soils to release micronutrients already present
·
Compost
·
Rock
powders such as Azomite®
·
Kelp
·
Fish
hydrolyzate, emulsion or meal (caution, may contain mercury, PCBs or other
contaminants). Be aware when choosing to use fish products that massive
over-fishing is causing severe ecological damage in oceans.
Prohibited
·
Any
synthetic source
·
Copper
sulfate
·
Iron
chloride
·
Chelated
iron
·
Ironite®
Blended
Fertilizers
Allowed
·
Products
containing only preferred and/or allowed mineral nutrients applied according to
these Standards
Prohibited
·
Products
containing any prohibited materials, including “transitional” or “bridge”
products
Liming
Materials/pH Adjustments
Preferred
·
Compost, compost
teas, leaf mold (These organic
materials will produce a pH moderating effect on soil, but only over time and
multiple applications. Inorganic materials such as limestone or
wood ashes will elevate pH much more rapidly.)
·
Leaf
mold
Allowed
·
Agronite
·
Calcitic
limestone
·
Dolomitic
limestone
·
Wood
ash
·
Granulated
sulfur (decreases pH)
Prohibited
·
Aluminum
sulfate
·
Synthetically-derived
products
·
Iron
Sulfate
·
Ironite®
Soil
Conditioners
Preferred
·
Composts
and compost teas
·
Cover
crops and green manures
·
Leaf
mold
·
Grass
clippings
Allowed
·
Humates
and fulvic acids
·
Greensand
·
Gypsum
·
Mulches
·
Organic
rock powders
·
Sugar
sources (molasses, glucose, sucrose)
·
Peat
moss (Although peat moss is widely used as a soil conditioner, we do not
recommend it because the harvesting of peat moss destroys increasingly rare bog
habitats.)
Prohibited
·
Synthetically-derived
products
·
Anything
containing sludge or biosolids
Microorganisms
and Inoculants
Allowed
·
Non-GMO
(genetically modified organism) microbial inoculants
·
Biodynamic
preparations
·
Compost
teas
·
Soil
bio-stimulants (beware of false claims
and synthetic ingredients)
Prohibited
·
GMO
(genetically modified organism) microbial inoculants
Soil
Mixes
Preferred
·
Compost-
or soil-based potting mixes free of prohibited substances
Allowed
·
Compost-free
mixes without prohibited substances
·
Yucca
extracts used as wetting agents
·
Addition
of beneficial fungi and/or bacteria to the mix
·