Paul
Sachs is the founder of North Country Organics and Ecological Turf
Consultants. He has authored a number of books on sustainable turf
care and sport field management. The following article by Paul was
recently published in a number of professional periodicals. It is
reprinted here with Paul’s permission.
Killing
the Messenger
When an eclectic group of ailments finally send you to
the doctor’s office and, after a barrage of tests, the
physician tells you to decrease your current level of stress, do you
then spray him with homicide? No! When the severity of heat,
drought, cutting height, and traffic all increase to a critical point
and your turf finally succumbs to disease, do you spray it with
fungicides? Yes! This analogy may not be bulletproof but here’s
the point: killing the messenger rarely corrects the problem. In
fact, it often makes the problem worse.
Evidence is mounting that pesticides and soluble
fertilizers dramatically alter the biological balance in soil. It is
also becoming clear that the suppression of specific groups of soil
organisms—especially beneficial fungi—affects the stress
tolerance and overall health of turf plants.
If we
take a superficial look at how soil life evolved, a relationship is
evident between the soil’s biological balance and the type of
plants that naturally proliferate. During the beginning stages of
soil development, only photosynthesizing (autotrophic) microorganisms
could exist. At this point the soil was completely dominated by
bacteria. These microscopic plants eventually produced enough
organic energy to support various groups of decay organisms
(saprophytes) that consumed the residues of the autotrophs. As these
saprophytes began to proliferate, more biotic diversity accumulated
and fungi began to appear on the scene. In the early stages of
fungal development bacteria still outnumbered fungi by a wide margin
but slowly, the ratio between fungi and bacteria began to narrow. At
the stage where visible plants had enough resources to grow, the
ratio of fungi to bacteria was probably about 0.1:1 (i.e., 1 fungus
to 10 bacteria). The only plants that could grow in this austere
environment were wildflowers and weeds but these plants contributed
resources to advance soil evolution. Eventually, the ratio of fungi
to bacteria (F:B) narrowed to about 0.3:1 and early species of
grasses began to appear. These grasses produced more resources for
fungal communities and as the F:B ratio narrowed more, later species
of grasses were able to proliferate. At this point the F:B ratio was
probably between 0.75:1 and 1:1. As soil fungi began to outnumber
bacteria (
2:1), more woody plants, such as shrubs and vines began to appear.
These plants were eventually succeeded by trees and as old growth
forests evolved the F:B ratio in the soil grew to between 100:1 and
1000:1.
Turf
naturally grows best in soil where the F:B ratio is somewhere around
1:1. As the ratio drops, grasses naturally thin and weeds and
wildflowers usually begin to appear. There is evidence that
applications of pesticides (especially fungicides) and soluble
nitrate or ammonium fertilizers can suppress fungal growth and
inadvertently favor a more bacteria dominated soil. This biological
condition does not naturally support a strong community of turf
plants. In response to the waning vitality of our turf, we typically
apply more soluble fertilizers to push growth and pesticides designed
to either suppress the plant’s competition (weeds) or pests
(attracted to stressed plants). Unfortunately, it is likely that we
are further inhibiting fungi’s ability to recolonize in the
soil.
The weeds, wildflowers, and pests are messengers. They
are trying to tell us that something is wrong and that our turf
plants are stressed. The problem may not be immediately evident but
the messengers make it clear that a problem does exist. If the soil
is fertile and not compacted, we may want to explore the possibility
of a biological imbalance.
Organic
Land Care Qualified Compost
for
Professional
Partners in Sustainability™
This
article is one relating to the Oregon Tilth Organic Land Care program
that is scheduled to be introduced next winter with a multi-day
training program and qualifying test. I will keep our Professional
Partners in Sustainability informed about the program as we go
through this year. I have been involved with the development of this
program for the last few years.
Certified
organic farmers are restricted in the use of compost on their crops
because some compost may contain pathogenic organisms that can
contaminate crops. All compost that does not meet the requirements
of CFR 205.203 must not be applied to crops within 90 or 120 days of
harvest, depending on the crop. CFR 205.203 requires compost used
within the “pre-harvest” interval to have a prescribed
carbon to nitrogen ratio and to have been held at a specific
temperature for a period long enough to kill any possible pathogens.
(It also kills weed seeds).
The
Oregon Tilth Accredited Organic Land Care program will require a
minimum standard of compost quality as well. Most major composting
facilities subscribe to a program of quality control, such as the US
Composting Council’s (USCC) – Standards of Testing
Assurance (STA) program. USCC does a comprehensive lab analysis on
the compost samples submitted and issues a report to the supplier.
The lab reports contain information on nutrient content, organic
matter levels, heavy metal contamination, stability, pathogen levels
and germination rates. Compost producers who participate in the STA
program are required to make a copy of the report available to their
customers upon request. USCC members who follow the sampling
protocols of the STA program are said to have “Certified
Compost”. The STA program is a tool for the compost industry
to monitor and improve the quality of their product but there are no
minimum levels of quality for the compost tested. It is possible
then that “USCC Certified Compost” could contain elements
or organisms that are harmful to people, soil quality and the
environment as a whole.
For
this reason, the Tilth program has been working with composting
facilities and a USCC authorized consultant to develop a minimum
standard of quality for compost used in their Accredited Organic Land
Care program. Organic Land Care Practitioners will be required to
specify this “Qualified Compost” when it is used for soil
incorporation or lawn top dressing, where it’s available, on
all sites managed under the Tilth program.
Major
composting facilities will be made aware of the Organic Land Care
Qualified Compost standards and encouraged to participate with Tilth
Accredited Practitioners in raising the bar on compost quality by
carefully monitoring the composting process to produce a high quality
product that meets the Qualified Compost standard.
Coming
Next Edition!
Willamette
University brings their whole campus under Organic Land Care
protocols.
