Phosphorus and Mycorrrhizae - Mycorrhizal
Applications, Inc (www.mycorrhizae.com)
What tips should I know when working with /
applying mycorrhizae?
High
levels of available Phosphorous (The "P" in N-P-K) does not harm or kill mycorrhizae,
but it can slow there progress. One of
the main functions of mycorrhizae is to extract
phosphorous.
However, if there is already an over abundance of phosphorous available to the plant, the
mycorrhizae
have no reason to “go to work” so to speak. This means they
won’t be
performing some of their other important tasks
like water uptake, and other nutrient
extraction as well.
You
really want to keep available phosphorous at a low to moderate level. This is most
important at the time of inoculation when
those spores are trying to attach to the plant and
assimilating to their new environment.
Some conditions to avoid:
_ High temperatures of 140 degrees F and above can kill the mycorrhizae, which could be
important to other manufacturers that
might be looking to process the mycorrhizae into
pellets for example or to people who want
to use before Composting.
_ Not all, but certain Fungicides can also
damage mycorrhizal fungi. Please see our
List of
Fungicides and their know effects, to help you pick a mycorrhiza
friendly fungicide.
_ Mycorrhizal fungi actually attach and
become part of the plant, they are not free living
soil organisms, they require that symbiotic
relationship, meaning they will stay with the
plant for the life-cycle of that plant. When
annual plants die, or a field is tilled, etc
those mycorrhizae do
not remain indefinitely, they die along with those plants.
How do you apply these mycorrhizal
fungi?
Mycorrhizal application is easy and requires no
special equipment. The goal is to create physical
contact between the mycorrhizal
inoculant and the plant root. Mycorrhizal inoculant
can be sprinkled
onto roots during transplanting, worked
into seed beds, blended into potting soil, “watered in” via
existing irrigation systems, applied as a
root dip gel or probed into the root zone of existing plants.
The type of application depends upon
the conditions and needs of the applicator.
Should I feed my mycorrhizae?
Molasses and other carbs are good
for feeding bacteria and other types of fungi. But you don’t
need to feed mycorrhizae.
That’s missing the point. The plant feeds them! It’s the sugars from
the plant roots that feed the growth of
mycorrhizae and mycorrhizal
filaments. (There are synthetic
compounds that cause mycorrhizae
to germinate, but they are unnatural, expensive and not
commonly available.) The use of organic
fertilizers, kelp, humic acids and other carbon
sources
are very compatible with the use of mycorrhizal fungi.
Don’t soils already contain mycorrhizal fungi?
Undisturbed soils are full of
beneficial soil organisms including mycorrhizal
fungi. Research
indicates, however, many common practices can
degrade the mycorrhiza-forming potential of soil.
Tillage, fertilization, removal of
topsoil, erosion, site preparation, road and home construction,
fumigation, invasion of non-native plants, and
leaving soils bare are some of the activities that can
reduce or eliminate these beneficial soil
fungi. Reintroducing mycorrhizal fungi in areas where
they have been depleted can dramatically
improve plant establishment and growth
Many
routine nursery practices, such as fumigation and dousing with high levels of
water and
nutrients,
produce non-mycorrhizal plants. When high levels of fertilizer and
water are provided
for non-mycorrhizal
plants, they can thrive in this artificial growing media, but they are ill
prepared to survive the eventual outplanted condition.
Can I use pesticides when I use mycorrhizal inoculants?
Fungicides:
Many commercial fungicides are compatible with
Mycorrhizal fungi, but not all. Some fungicides
are known to damage or suppress these
organisms. Please see our List of
Fungicides and their
known effect.
Fungicides applied as seed
treatments, even those indicated on our List as “avoid use” are usually
compatible with Mycorrhizal
inoculants because they provide a small amount
of fungicide that is
quickly removed from the root zone. Foliar
applications of non-systemic fungicides are
compatible with mycorrhizal
inoculations. For soil drench utilization of fungicides, the
application
should be done 2 weeks before the
inoculation or 3-4 weeks later. If a fungicide known to
adversely affect mycorrhizal
fungi is applied after mycorrhizal
colonization has been achieved,
the host plants temporarily
lose external filaments, but because mycorrhizal
structures have already
been established internally in the
root, they will quickly reproduce those external filaments that
were lost.
Herbicides:
Most herbicides
are generally considered compatible with mycorrhizal
inoculation but several
have yet to be specifically tested for mycorrhizal compatibility.
Insecticides, nematicides:
Insecticides and nematicides
are generally compatible with Mycorrhizal
fungi but several
have yet to be specifically tested for mycorrhizal compatibility.
How do mycorrhizal
fungi increase nutrient uptake?
These fungi increase the surface
absorbing area of roots 100 to 1,000 times thereby greatly
improving the ability of the plants to
utilize the soil resource. Estimates of amounts of mycorrhizal
filaments present in soil associated with
plants are astonishing. Several miles of fungal filaments
can be present in less than a
thimbleful of soil! But mycorrhizal fungi increase
nutrient uptake
not only by increase the surface
absorbing area of roots, they also release powerful chemicals
into the soil that dissolve hard to capture
nutrients such as phosphorous , iron and other “tightly
bound” soil nutrients. This extraction
process is particularly important in plant nutrition and
explains why non-mycorrhizal
plants require high levels of fertility to maintain their health.
Mycorrhizal fungi form an intricate web that
captures and assimilates nutrients, thus conserving
the nutrient capital in soils. In non mycorrhizal conditions much of this fertility is wasted or
lost from the soil system.
What other activities do mycorrhizal fungi do?
Mycorrhzial fungi are involved with a wide
variety of other activities that benefit plant
establishment and growth. The same extensive
network of fungal filaments important to nutrient
uptake is also important in water uptake
and storage. In non-irrigated conditions, mycorrhizal
plants are under far less drought stress
compared to non-mycorrhizal plants.
Mycorrhizal fungi also improve soil structure. Mycorrhizal filaments produce humic
compounds
and organic “glues” (extracellular
polysaccharides and glycoprotiens) that bind soils
into aggregates
and improves soil porosity. Soil
porosity and soil structure positively influence the growth of
plants by promoting aeration, water
movement into soil, root growth, and distribution. In sandy or
compacted soils the ability of mycorrhizal fungi to promote soil structure may be more
important
than the seeking out nutrients.