C. 1. Understanding Compost Tea
1. Why Use compost tea?
tea is used for two reasons: To inoculate microbial life into the soil or onto the foliage of plants, and to add soluble nutrients
to the foliage or to the soil to feed the organisms and the plants present. The use of compost tea is suggested any time the
organisms in the soil or on the plants are not at optimum levels. Chemical-based pesticides, fumigants, herbicides and some
synthetic fertilizers kill a range of the beneficial microorganisms that encourage plant growth, while compost teas improve
the life in the soil and on plant surfaces. High quality compost tea of will inoculate the leaf surface and soil with beneficial
microorganisms, instead of destroying them.
What is compost Tea?
Compost tea is a
liquid produced by leaching soluble nutrients and extracting bacteria, fungi, protozoa and nematodes from compost. The brewing
process is performed at constant temperature, although the growth of the organisms may elevate temperature as a result of
their reproductive heat produced.
Tea production is a brewing
process, and as easy as making beer or wine. But we all know that wine or beer brewing isn’t that easy. Brewing compost
tea can be fraught with problems. But if you think about what you are doing, and pick out the right tea-making machine, making
compost tea that will help your plants is easy as flipping a light switch. What is your purpose in making tea? If you want
to inoculate a highly beneficial group of bacteria and fungi, protozoa and possibly nematodes, buy good compost that has these
organisms, and make Actively Aerated Compost Tea. There are a number of excellent tea makers on the market (see How to make
Benefits of using of compost tea containing the
WHOLE foodweb include:
- Improve plant growth as a result of protecting plant surfaces with beneficial
organisms which occupy infection sites and prevent disease-causing organisms from finding the plant,
plant growth as a result of improving nutrient retention in the soil, and therefore reduce fertilizer use, and loss of nutrients
into ground- and surface waters
- Improve plant nutrition by increasing nutrient availability in the
root system as predator-prey interactions increase plant available nutrients in exactly the right place, time and amounts
that the plant needs,
- Reduce the negative impacts of chemical-based pesticides, herbicides and
fertilizers on beneficial microorganisms in the ecosystem
- Improve uptake of nutrients by increasing foliar
uptake as beneficial microorganisms increase the time stomates stay open, while at the same time reducing evaporative loss
from the leaf surface,
- Reduce water loss, improve water-holding in the soil, and thus reduce
water use in your system,
- Improve tillage by building better soil structure. Only the biology builds
soil structure, and ALL the groups in the foodweb are required to be successful. You can’t have just bacteria, you must
have fungi, protozoa, nematodes and microarthropods as well! Please be aware that plate count methods don’t tell you
about the whole foodweb.
in compost tea?
Tea contains all the soluble nutrients
extracted from the compost, but also contains all the species of bacteria, fungi, protozoa and nematodes in the compost. Not
all the individuals in the compost, but representatives of all the species in the compost are found in the compost tea. Making
sure only beneficial species are present in the compost is therefore critical.
Outdated methods of assessing numbers of organisms in samples might lead you to believe compost tea doesn’t
have much diversity. But, consider that species diversity in soil is much, much greater than plate count data would lead people
to believe. Plate counts miss 99.99% of the bacterial and fungal species in soil. You need to use molecular methods to understand
true species diversity in compost.
Plate count assessments
of diversity in compost and tea, and soil should not be used. They are misleading about the true diversity, or even as an
indicator of diversity in soil, compost or compost tea. Good, aerobic compost contains a huge diversity of organisms.
Foods extracted from the compost, or added to the tea, grow beneficial organisms.
A large diversity of food resources is extracted from compost. The species diversity of organisms in the tea is much higher
than those hundred or so species of bacteria that grow on the food resources added by people. Together, the beneficial bacteria
and fungi growing on the compost foods, and on the added foods, result in a many individuals of many different species. Molecular
diversity analysis is required, however, to assess even a small portion of the species present in compost tea.
Only aerobes are desired. Anaerobes make alcohols that kill plant tissues
very rapidly. Putrifying organic matter, which is anaerobic, also contains organisms, just not organisms that do anything
beneficial for your plants.
Most introductory microbiology
books can answer most questions about the controversy between direct enumeration and plate count approaches. Reading the sewage
treatment literature also points out clearly the conditions that allow E. coli to grow, which means reduced oxygen atmosphere.
In full aerobic conditions, only if the beneficial bacteria have been killed or harmed can E. coli win in competition with
The list of papers specific to compost
tea and compost have been summarized by Steve Diver, and are listed on the ATTRA website, www.ATTRA.org
When buying a tea machine, you should ask the manufacturer to
provide information about oxygen during the tea brewing cycle in the compost basket or bag. You should insist on being given
molecular analyses of diversity, and total and active bacteria and fungi, and protozoa, present in the tea made under standard
The METHOD is critical in
In order to have the organisms in the tea,
brewing conditions must be correct to produce the end product desired.
The biology that is active and performing a function
will be very different, depending on:
- temperature of brewing,
foods added to the brew,
- oxygen concentrations in the brewer during production,
initial compost used, and therefore which species are present to be extracted,
- The length of time
tea is brewed.
Temperature during brewing should be related to the temperature of the soil,
or of the leaf surface. If tea is applied in the late autumn, when temperatures are cool, it may be wiser to apply a tea where
the organisms are mostly asleep, or that are selected to grow on plant residues. Selection for this ability would be enhanced
by addition of plant material to the brew, such as oatmeal, alfalfa meal, feathermeal, etc.
added to a brew will select for particular species that can use those foods. Do you want a bacterial tea? Add sugars, simple
proteins, simple carbohydrates. If a fungal brew is desired, add more complex foods, such as plant material (oatmeal, soybean
meal, flour), humic acids, fulvic acids (which will release bacterial foods after fungi begin the process of decomposition).
Predators can be enhanced by adding hay (cut green and dried), or by soaking hay for a few days and adding the water to the
Oxygen is perhaps the parameter that has been least understood in centuries
of tea-brewing. Most beneficial organisms, the organisms that promote the processes that plants need in order to grow without
stress, and therefore with greatest resistance to disease, are aerobic organisms. To enhance this community of beneficials,
tea must remain aerobic.
Fermentative microorganisms are
organisms which can grow in aerobic as well as reduced oxygen conditions. Since these organisms have dual metabolic abilities,
they have to maintain the genetic material for both sets of enzymes. They have an energetic load that means they are not as
competitive with true aerobes, when oxygen is in fully aerobic concentrations. They are not as competitive when in competition
with true anaerobes at low oxygen concentrations. They do best in the conditions where oxygen is fluctuating in the intermediate
aerobic – anaerobic range. These organisms can make very interesting waste products when growing in anaerobic conditions.
These materials are known to have significantly inhibitory effects on a variety of less-desirable organisms.
The problem is maintaining the conditions exactly correctly so that the desired
organisms grow. This knowledge is not public domain, and remains proprietary. Until attention is directed to understanding
what products result from different aerobic – anaerobic conditions, with which foods, and with different temperature
regimes during brewing, fermentative compost teas remain in the questionable realm. These teas don’t produce the same
effects time-after-time, which is the reason that compost teas have languished in the “snake-oil”, and “voo-doo-juice”
category for so long. If the tea you brew today has one effect, but the tea you brew tomorrow has a different, and possibly
negative effect, that lack of reliable results will destroy the reputation of a product. It is most important to clearly maintain
production conditions when making tea.
(below 2 to 4 mg oxygen per L for example) during brewing can result in the growth of some quite detrimental microbes and
production of some very detrimental metabolites. It is best to avoid extremely low oxygen concentrations during brewing, or
if low oxygen concentrations occur, brewing must continue until the organisms stop growing on the added foods, such that oxygen
will diffuse back into the brew. Only after the brew returns to the aerobic conditions should it be used on plants or soil.
If you want to make a mix of unknown, but possibly quite
anti-bacterial, or anti-fungal materials, then a fermentative approach might be best. The specific conditions needed for production
of a consistent mix set of inhibitory substances are not well-documented. More work is needed to understand production parameters
for this kind of tea.
Is compost or compost
tea "better" if it is aerobic or anaerobic?
that cause human diseases almost invariably require anaerobic or reduced oxygen conditions in order to survive in competition
with aerobic organisms. Only in reduced oxygen, or anaerobic conditions, can human disease-causing organisms out-compete the
normal set of beneficial bacteria or fungi growing in soil, compost or compost tea.
If you’ve done a good job choosing or making your compost, the compost will not contain any
human disease organisms. The tea will not contain human pathogens if there were none in the compost. What do you need to know
in order to be assured that the compost contains no human pathogens? The temperature cycle of the compost. Insist on getting
that data from the compost maker. What do you care about the amount of nitrate, if there are human pathogens in the “compost”?
If the compost was kept fully aerobic, and temperatures
between 135 F and 155 F were maintained for 10 to 14 days, or the compost was processed by adequate numbers of earthworms,
the likelihood of human pathogens in the compost is just about nil. Contamination of finished compost by something else containing
pathogens is possible so be aware that this can be a problem too.
the compost wasn’t processed correctly and disease-causing organisms weren’t destroyed by temperature, competition
with beneficial organisms, or passage through earthworms, the probability is reasonable that disease-causing organisms will
grow rapidly and be in high numbers in a tea that goes through reduced oxygen, or anaerobic, conditions.
If the tea was made with good compost (high numbers of beneficial bacteria,
fungi, protozoa, nematodes; good soluble nutrients) using aerobic conditions, there is little likelihood that human pathogens
could grow, because not only are conditions not correct for their growth, but they will be out-competed and inhibited by the
aerobic bacteria and fungi growing in those aerobic conditions.
It is critical to know that the tea maker you are using can maintain aeration rates greater than
the rate the bacteria and fungi use up the oxygen.
or carbon dioxide can be monitored to determine whether aeration is adequate throughout the whole brewing cycle, and in all
parts of the machine. Please be aware that the data needed are from the inside of the compost basket, or inside the compost
bag. Currently, all national level compost tea manufacturers display SFI data on their websites, with only two exceptions.
People who bought machines from these two companies have sent data to SFI showing that either inside the compost baskets or
the bags, the tea went anaerobic during tea brewing, or serious anaerobic bio-films develop in places that you can’t
see or can’t reach easily during cleaning.
in the tea should not fall below 5.5 to 6 ppm dissolved oxygen, which is typically about 70% dissolved oxygen, or 15 to 16%
oxygen when measuring total atmospheric gases. These values change based on altitude and temperatures, so make sure the oxygen
probe comes with information on typical maximum oxygen levels, which is where your water in your tea maker will start out.
You can’t tell whether oxygen use, or carbon dioxide production, was
performed by bacteria or by fungi. Since you need to know, at least occasionally, the ratio of fungi to bacteria your tea,
you need to test your teas so you can be certain you are making disease suppressive tea.
Fungi grow very well indeed in compost tea.
For good fungi in tea, first of all, fungi in the compost have to be extracted adequately.
This is a function of two things, presence in fungi in the compost, and rapid enough water movement through the compost to
pull the fungi off the compost particles. Work with Bruce Elliott of EPM (email@example.com) has shown how easy it is to get great extraction and growth of fungi
in the tea.
The EPM, KIS, WormGold, and BnBrewer machines
in the US, Tea-riffic® in Canada, the Compost Tea machine in New Zealand, and Compara
in Europe, in do excellent jobs of extracting fungi from the compost and allowing it to grow in the tea. Testing, over one
to two years, shows that these machines continue to make good tea. Machines with hidden surfaces that develop biofilms do
not maintain good tea production over time.
from companies that cannot pass SFI standards like to say that “fungi don’t grow in tea”, or “there
are lots of fungi in the soil already”. Please realize that what they are actually telling you is that the machines
they sell do a poor job of extracting fungi and growing fungi. Fungi can be extracted and grow quite well in tea.
When soils have been treated with fungicides, including copper sulfate, or
sulfur, the soil cannot possibly maintain normal levels of beneficial fungi. Adequate beneficial fungal biomass does not occur
in any field treated with fungicide, insecticide, bactericide, nematicide, herbicide or high levels of inorganic fertilizer.
Fungi require foods to feed them
If the compost contains complex food resources, that can be enough to feed
many fungal species, but usually additions of humic acids, and complex nutrient resources enhance the growth of beneficial
species. People involved in making tea often research nutrient food resources. Hendrikus Schraven Landscaping (firstname.lastname@example.org), EPM (email@example.com) and Leon Hussy at KIS (www.simplici-tea.com) make some outstanding food resources for bacterial and fungal teas.
Many ideas for foods for bacteria and fungi can be found on the compost_tea list serve, firstname.lastname@example.org
Species diversity is the same in compost and the tea made from that compost. Species diversity
in compost is higher than fumigated or sick soil. But at least one plate count microbiology lab is giving out data suggesting
that compost has lower diversity than bad soil and that “ok” tea has less diversity than bad compost. It is clear
that plate count “diversity” methods are not effective in assessing species diversity, or species richness, in
soil, compost or compost tea. Molecular methods tell us that species diversity in soil, tea, and compost, can number in the
thousands and tens of thousands per gram.
Use of methods
that tell you that soil contains only a few 5 to 10 species, or that compost contains only 8 to 15 species need to be viewed
with a great deal of incredulity. Plate methods are missing only about 99.9% of what is actually present!
Do plate counts or direct counts assess tea quality? The clear answer is that
direct counts assess tea quality, while plate counts do not. Take a look at the results (below) from a test where two different
teas were used to control blight on tomato plants.
Multi-layer fabric, or felt, bags are a poor idea,
because the hyphae get held in the fabric, and mildew grows in the damp material. Single layer, nylon or netting bag material
Time to brew
Small, well-aerated, well-mixed compost tea makers can give great tea within
10 to 12 hours. The KIS machine gets great organism extraction and growth of the beneficial organisms in 12 hours, based on
direct counts of the individual bacteria, measurement of biovolume of fungal hyphae, enumeration of protozoa and nematodes
from those teas.
Pay attention when you buy a machine
or develop a design. Different tea machines take different amounts of time to brew good tea. Especially those machines that
take 48 hours or more to brew a decent level of organisms in their tea, the salespeople tend to be very reluctant to tell
you exactly how long the tea takes to reach a certain organisms-in-the-tea level. For example, some machines take a minimum
of 48 hours to brew the tea, and as a result, tend to have more problems with becoming anaerobic.
Several “tea-brewer” manufacturers have no data about maximum bacterial or
fungal production with their machine, and certainly no clue at all about protozoa or nematode numbers. Their salespeople will
tell you their tea is ready in 24 hours, but they don’t have any data to prove this to you. Buyer beware!
What is the shelf life of compost tea?
The shelf life is short in high quality tea with active organisms necessary
to attach to lead surfaces and not be washed off. In the research that we have done with 24 hour brewing cycles, after just
6 hours without any aeration, the oxygen levels are lowered by over 300 %. If the compost tea is not used within that time,
aerate, agitate and add more food to the tea to feed the micro-organisms.
C. 2. How does the Foliar Food Web affect plants?
Foliar organisms create a protective layer on leaves, stems, blossoms, fruit
and any above-ground just as happens in the soil, around roots.
dynamic, living system on the aboveground parts of plants is constantly impacted by rain, wind, heat, sunlight, and pollution.
Often disease can gain a foothold after some disturbance harms the community of beneficial, plant-surface dwelling organisms.
Understanding foliar health requires knowing:
organisms should be present (community analysis),
- how many are present (total biomass of each group),
- how many should be functioning (active biomass).
Healthy Leaves, Soil, or any System requires:
that cycle nutrients into the right forms at the right rates need to be present on the foliage in the right diversity, in
the right number, in the right places (growing on the exudates plant surface release) with the right level of activity,
to prevent disease-causing organisms from being able to find a foot-hold on leaf or plant surfaces,
that cause plant stomates to open and remain open longer so nutrients added with the microbes will be pumped into the leave
surfaces more rapidly, when the plant is supplying foods to make microbial activity occur,
to degrade toxic materials, especially air-borne pollutants,
organisms present in the soil, or on leaves, or in compost just automatically?
NO, they are not. Consider all the toxic chemicals human beings release on a daily basis. Consider air pollution.
If air pollution is killing human beings, think of the damage to smaller, less well-protected individuals. Dust, and toxic
pesticides and salts are being poured out onto soil, onto plant surfaces, each day. Natural disturbances (freeze, thaw, wet,
dry, fire, and compaction) can kill critical organisms as well. We need to learn the impact of all disturbances, whether human-generated
or natural occurrences. We need to learn how to replace, encourage and select for the presence of the appropriate organisms.
If nature kills organisms through natural disturbance,
we need to know how to return to what is needed for the crops we want, just as we need to know how to return the organisms
to what is needed after we use any chemical, for whatever reasons. It would be better not to let disturbance kill the organisms
we want, but sometimes, we just don’t have any choice. We have to learn how to nurture the right biology and bring it
If anything has been harmed or reduced, or put out-of-balance,
the appropriate organisms must be returned to the plant surfaces if they have been harmed or reduced in diversity or biomass.
If the organisms that perform these benefits are missing, they need to be replaced.
The foliar food web will not contain the higher level predators. In unusual disease or pest outbreaks,
such as ants farming aphids on foliage, it may be necessary to discourage the ants from this behavior by adding some ant-pathogenic
fungi into their nests, or adding the fungi to the tea brew so the ants pick up the fungus and take it home with them on their
Foliar pests can be discouraged by the smell, the
taste, or the tackiness of the leave surface that foliar compost tea brews leave behind. The precise mechanism needs to be
determined for why this works.
Bacteria are typically the
dominant microbe on leaves, twigs, branches, blossoms and bark. Decomposer or saprophytic fungi are also present. Both bacteria
and fungi use the exudates produced by the plant, by algae or lichen growing on plant surfaces or deposited by through-fall
or other deposition processes. Maintenance of the proper coverage of organisms on the leaf surfaces is critical to maintaining
disease suppression in the foliage of any plant.
can the Soil and Foliar Food Web be assessed?
have been developed that allow the numbers, types and activity of each important group in the soil and on plant surfaces to
be quickly assessed. The kinds of assessments used are:
- Number of individuals or biomass
of each group
- Type of organisms present and who is dominant
- How active the organisms
- Relation of soil organisms to plant available nutrients
All of these methods need to be performed by direct microscopy, not by plate counts, enzyme
assays, or other in-direct assessment methods.
C. 3a. How
to make Actively Aerated Compost Tea
Aeration must be adequate
to extract the maximum amount of soluble nutrients, and to maintain oxygen in aerobic concentrations in order to produce a
tea high in aerobic bacteria and fungi, and with maximum extraction of protozoa and nstrongatodes. The more diverse the community
of microorganisms extracted and grown under aerobic conditions, the greater the disease suppression and the better nutrient
retaining the tea will be. The greater the concentration of nutrients extracted, the more food there is to grow beneficial
bacteria and fungi in the tea during the brewing cycle and after the tea is sprayed out.
It is CRITICAL to understand that tea must rstrongain aerobic. If too great a concentration
of food resources for the bacteria and fungi are added, the growth of the organisms will be so rapid, that they will consume
oxygen more rapidly than oxygen can be added into the tea. The tea will go anaerobic, and then human pathogens can grow in
Any compost tea machine can be caused to go anaerobic,
if too much microbial food is added, too much compost, and aeration is lacking.
Compost tea is used to add bacteria, fungi, protozoa and nstrongatodes to the soil or onto foliage.
Compost tea also contains soluble nutrients that feed the organisms in the tea and may feed plants. Use compost tea any time
organisms in the soil or on the plants are lower than optimum levels. Chstrongical-based pesticides, fumigants, herbicides
and some synthetic fertilizers kill the beneficial microorganisms that encourage plant growth, either in the soil or on foliage.
Compost teas improve the life in the soil and on plant surfaces and help plants take-up the nutrients they require, and suppress
diseases at the same time as building soil structure, and reduce erosion and loss of nutrients into drinking water. High quality
compost tea of will inoculate the leaf surface and soil with beneficial microorganisms, instead of destroying thstrong.
Given a good set of organisms (see Compost Tea Standards for what those numbers
are), the following benefits can be brought about:
- Improved plant growth
application rates of chstrongical pesticides, herbicides and fertilizers
- Reduced impacts of
chstrongical-based pesticides, herbicides and fertilizers on beneficial microorganisms in the ecosyststrong
of infection sites on the plant surface so pathogens cannot infect the leaf
- Improved uptake of
plant nutrients through influences on stomata,
- Increased numbers of organisms on and around plants
to compete with disease-causing organisms, reducing disease incidence,
- Retention of microorganisms
in soil or on leaf surfaces, resulting in an increase in retention of nutrients,
- Increased plant nutritional
- Production costs are reduced
- Reduced application of toxic chstrongicals, thus
reducing run-off into lakes and streams,
- Reduced toxic impacts on humans and pets.
Step-by-step Approach to Making AACT
One, choose a compost tea machine that has documented
ability to extract and grow the beneficial organisms from the compost you are using.
Here’s a list of brewers on the market in the US. We will be putting up a list of
brewers from outside the US in a short period of time.
Dstrongonstrated to Make Good Compost Tea, Grow Beneficial Fungi in the Tea Maker. These are not
in any particular order!
- EPM, Earth Tea Brewers – 100 ($3,500) and 500 gal
Excellent extraction (composttea.com)
- KIS brewers – 5 ($99) and 25 gal Good extraction,
easy to clean!!!!! (simplici-tea.com)
- Alaska Giant – 1 ($40) and 5 ($80) gal,
good extraction, soaker hose (alaskagiant.com)
- Ground Up – 50 gal and larger
- Sottilo - JAMSOT@aol.com Brewers made to order
Dstrongonstrated to grow bacteria, and usually only anaerobic bacteria
6.5 gal ($400), 30 gal, 250 gal (soilsoup.com)
Growing Solutions – 25 ($1300), 100 ($5000) and 500 ($12,000)
Figure out the amount of tea you need to put out at any one time. If you can
put out 5 gal today, and 5 tomorrow, and 5 the day after, why buy a machine that makes 50 gal? If you own 10,000 acres, ok,
you need a big machine. If you own an acre or less, a 5 gal machine will likely do fine.
Read and ask questions on the compost-tea list serve (http://groups.yahoo.com/) put 'compost_tea' in the search box, relative to each brewer you are
You need a tea brewer that the seller can
document oxygen rstrongains in the aerobic range!
a graph showing the type of information you need.
case, the red line is oxygen concentration in the water (in ppm or mg oxygen per L of water), and the green line is the active
biology in the tea (micrograms of active bacteria and active fungi per ml of tea). When the organisms are growing the most
rapidly, activity peaks (after about 16 hours in most brewers, although about hour 8 in small brewers).
The reason for the peak is that the microorganisms have maximized use of foods,
and after that peak, their activity slows down, because they are running out of food. Activity usually stabilizes about 24
hours, so it is safe to take the tea out of the max aeration brewer and put it into a sprayer tank that has just re-circulation.
If the aeration is turned off, it typically takes some time for the organisms
to use up the air, and plunge into anaerobic conditions. A truly stable tea would only slowly use up oxygen and go anaerobic,
usually in about 5 to 6 hours. But if the tea is not in a stable condition, then when aeration is turned off, oxygen levels
will plunge within mere minutes to low, anaerobic levels.
Two, find a GOOD source of compost! Ask the compost maker for documentation of the bacteria, fungi,
protozoa and nstrongatodes in the compost. If they don’t have the data, they have probably tested, and couldn’t
show that their compost really is compost. Lack of data often means they can’t make the grade. You have to have the
beneficials in the compost in order to make good tea. You may want to read over the compost section of this website to find
out the desired levels of the different organism groups.
Three, decide on the foods you want to use to grow the beneficial organisms in your tea.
The company you bought your tea maker from has a proprietary blend of foods that go with their tea machine, balanced already
for the oxygen-use of that set of foods, and the ability of the machine to replenish oxygen during the growth of those organisms.
It is critical that aeration be adequate. Alternatively, you can design your own tea recipe, but this will take some testing
to make sure you are NOT adding too much food, and reducing oxygen, through the growth of the beneficial organisms, below
aerobic levels. Foods that should be considered are:
- a diversity of sugars for
bacterial growth, but realize that often the compost itself contains adequate bacterial foods to grow a great set of bacteria.
Addition of more bacterial foods can just cause problstrongs.
- Citric acid to help buffer pH to
the right level, as well as feeding beneficial bacteria
- Cold-water kelp (higher in nutrients) to serve
as a source of micro-nutrients (K, Co, B, etc, please check the label of the product you buy to make sure you are adding micronutrients
you need. How do you know micronutrients are needed? A soil chstrongistry, or plant tissue test might be a good idea)
acids fro fungal growth, but realize that you want data to show you that this material can actually help grow fungi. Harsh
extractants can make the humic materials very difficult for fungi, or anything else, to use.
Four, you need a means of transferring the tea from the tea brewer
to the soil, or to the foliage of your plants. With small size tea brewers, pouring the tea into a sprayer works well. But
with larger volumes of tea, you will need a transfer pump to move the tea into the sprayer unit. You need to talk to your
tea machine maker and find out the testing that they have done to make certain that the pump doesn’t destroy the organisms
in the tea as it is being transferred.
is a tea maker on the market, clearly one not recommended by SFI, where the transfer pump kills about 50% of the organisms
in the tea. So even though that company posts plate count data showing there is bacteria in the tea made by that machine,
moving the tea out of that machine into your sprayer will kill about half the organisms in the tea. Please be aware of these
kinds of snake-oil salesmen!
you need a sprayer that will distribute the organisms evenly on the leaf surface. Typically any sprayer meant to apply pesticide
will evenly apply tea organisms. The only thing that needs to be checked is that the sprayer re-circulates tea while the tea
is in a large size tank (back-pack sprayers or smaller don’t need this, it typically doesn’t take hours to apply
tea in small amounts), and that the pump used by the sprayer doesn’t kill organisms either. Talk to the tea machine
makers about their lines of spray equipment.
affecting Compost tea Quality
- Compost source – make sure it contains the organisms your plant
- Compost tea bag or container – the simpler the better, but opening sizes have to be right
time – longer is not better
- Brewing tstrongperature – make it right for the syststrong
the tea will be sprayed on!
- Water source – get rid of chlorine, chloramines, sulfur, other
- Extraction – the organisms have to be ripped off the compost, but not harmed
in the process!
- Amount of tea applied to the soil or to the foliage – 5 gallons per acre for
each 6 feet of foliage height, 20 gal per acre for the soil applications are the latest test results using EPM, KIS, BnBrewer,
Clarke, AG, CT Brewer (NZ), and WormGold brewers.
If you are going for the bigger
machines, pay attention to the kind of pump on the machine. Did the manufacturer check to see if his pump kills organisms?
Where are his data? Don't accept "trust me". There's a machine on the market that we dstrongonstrated to the manufacturer
that his pump to take the tea from the brewer into a holding tank was reducing numbers of fungi and bacteria by 50%. Keep
that in mind, when buying something. How are you getting large volumes OUT of the tank?
Ease in cleaning is important.
Can you get to the bottom of the tank? Are there square corners in the pipes, knowing that in a month
or so, that corner will be bio-film filled. It isn't right away that the problstrong develops. With the commercial Microb-Brewer,
altered from the original design we tested at OSU, the pipes and pumps were changed to make the machine look prettier. The
numbers on the changed machine were similar to the original, not-pretty design for the first couple of runs, but then, look
out, the numbers dropped terribly as the bio-film developed. The manufacturer claimed that our methods had gone awry, that
we didn't know what we were doing, because the numbers were coming out lower. It wasn't us, it was bio-film. But the manufacturer
got mad at me. Stopped speaking to me all together. Called me all sorts of bad things.
SFI just tests the tea, we don't have to know why the numbers are coming out poorly. Usually
I try to figure it out, and with the Microb-Brewer, we did figure it out. But not until after the damage was done. The Microb-Brewer
is no longer for sale in the US.
Are there surfaces in
the machine you can't see, can't get to to clean? Those places build-up biofilm. There's a brewer on the market that has discs
in it, and you can't see, and you can't reach, the bottom sides of the discs. It is not fun getting the discs out to clean
their bottomsides. Think about the time involved in cleaning. Most LARGE brewers should have a way to rinse the tank down
as you pump the tea out. Talk to Bruce Elliott on this one. He developed the solution for this.
The compost container has to allow free movement of the compost.
Solid baskets that don't allow compost movstrongent, that allow the compost
to compact in the bottom, are going to cause you fits. Compost should be in bags, so easy-flow is possible. The EPM baskets
are there to keep the bag of compost from twisting in the water flow, so the compost isn't constricted in that bag-basket
design. But any other brewer with a basket has to have an aerator inside the basket, or the compost compacts, and goes anaerobic
(happens at about 10 hours into the brew, so beware of the brewer that only has data for hours 0, 8, and 24)
Bubble sizes should be medium to large, not micro-sized.
Tiny, tiny bubbles are a bad idea. They shatter the fungal hyphae. Ask for
the data showing good FUNGAL results. And please make sure the lab they are testing with uses decent methods.
No data? Don't buy the machine.
Only plate count data? Don't the machine. Ask what plate count data mean. Typically, you'll get gobble-de-gook
as a reply. There are no data documenting a consistent relationship between plant growth and plate counts. C. 3c. Long-Brewing Compost Tea
teas that start aerobic, move into the anaerobic ranges, and because they are brewed long enough, return to aerobic fall into
this category. They contain aerobic bacteria, and put-to-sleep anaerobic bacteria. Beneficial fungi, protozoa and nematodes
have been pretty much destroyed by the anaerobic phase, although if the brew didn’t actually go anaerobic, then the
beneficials may still be present.
These brews may contain
some remnant anaerobic smells and materials. The diversity of food resources has clearly been increased, but the question
remains what bacteria exactly were grown? Beneficials, or detrimentals? Disease-suppressors, or disease?
Disease-causing organisms often prefer, and grow better, in reduced oxygen
condition. But if the brew went quite anaerobic, then the diseases were killed too. How low is low enough? When do the “bad
guys” die, and when do the really bad guys, like Clostridium botulinum, start to grow? We don’t know.
What mix of foods results in the fermentative bacteria or fungi winning, versus
the human pathogens? Is stirring vigorously at 12, or 16 hours going to select for the good guys enough to maintain the good
guys? Or do you need to stir at 8, 12 and 24 hours? No one really knows. (If you do, please let me know, I’d like to
see your data).
Most Biodynamic brews fit this LBCT definition,
except Biodynamic preps do not always use compost. The preparations are plant teas, which means plant material is placed into
water, stirred and the biology on the leaf surfaces grows using the sugars, proteins, carbohydrates, cellulose, and more recalcitrant
(hard-to-decompose, quite complex and thus hard to attack) kinds of substrates.
Does that mean plant teas have no benefit? Of course NOT. If beneficial organisms are on the plant
surfaces (and usually roots are included in the plant teas), the beneficial organisms will grow and increase in numbers or
biomass during the brew cycle. Which good guys? It depends on the same factors as actively aerated compost depends –
temperature, mixing, aeration, foods added, the age and stage of the plant (and therefore the actual foods added), etc.
But, in these LBCTs, no aeration other than occasional stirring is added.
That means, if there are organisms present on the plant material, or in the compost if this is truly compost tea, the brew
is very likely to go anaerobic for some period of time.
for how long? And how low did oxygen go? And when did the growing organisms begin to run out of food, so that their oxygen
use rate slowed? When did their metabolism slow down enough that oxygen began to diffuse back into the water faster than the
organisms were using the oxygen?
By the end of a LBCT brew,
the tea should no longer stink in any way, which means the tea has returned to the aerobic condition. The things that may
kill your plant have been re-cycled back into bacteria biomass. Sorry, no fungi left in a brew that went anaerobic. The beneficial
fungi are, for the most part, aerobic.
The time, or the
conditions to allow conversion from aerobic to anaerobic and back again are not documented at all for these kinds of teas.
That means that sometimes positive effects have been observed using these kinds of teas, but other times the teas have had
no observable effect, and sometimes these teas kill plants. I’ve killed quite a number of plants using anaerobically
produced tea, and while I have not published this data (it is hard to publish negative results), lack of publication does
not mean it doesn’t happen.
That is why compost tea
has been regarded as witchcraft, or voo-doo, or snake oil for all these years. The results have been too variable to make
sense of what is going on. When sometimes great results occur, sometimes nothing, and sometimes really bad things happen,
no one is inclined to put much trust in the results.
the Biodynamic approach controls many of the factors involved in tea making, IF THE PRACTIONER PAYS ATTENTION TO WHAT STEINER
SAID. I’ve watched a number of biodynamic brews being made where part, or just about all of Steiner’s advice was
ignored. If people don’t understand WHY something was required by science, they may ignore it. But then typically the
results aren’t what you would want, or they do not give you the benefit you should be able to get.
The bottom line is, we need to put more effort into understanding these types
of tea. But for now, until the work is done, either do what Steiner said, exactly, or use AACT. We are really getting a handle
on how to guarantee that AACT is consistent, and beneficial, each time. Without an oxygen probe, and the time to monitor properly,
FCT and LBCT remain of questionable benefit.
C. 4. How to tell a "good" tea
Soil Foodweb Inc performed a study of how do you know if compost tea will “work”?
The results (given below in Table 1). clearly show that plate counts are inappropriate for determining
whether a compost tea will protect plant surfaces from disease. Direct determinations were excellent means of showing that
tea can protect leaf surfaces from disease causing organisms.
Plants were obtained from
a greenhouse where blight was causing a severe problem. All plants used were just beginning to show “burn” on
the leaves from the disease.
Five of the plants were sprayed
with Tea One, five plants sprayed with Tea Two. Control plants (water alone) and fungicide treated plants died within a week,
as did the plants to which tea one (tea lacking suppressiveness, see table below) was applied.
Does the fact that plants sprayed with Compost Tea One died mean that compost tea does
not work? No, because the plants sprayed with compost Tea Two (tea capable of suppressing disease in the table below) survived
and grew well.
What was the difference in the teas? Tea
Two, designated tea capable of suppressing disease in the tbale below, had high levels of active and total fungi, active and
total bacteria, and good protozoan numbers. Application of these organisms to the plant foliage resulted in excellent coverage
of the leaf surfaces. All of these plants lived.
designated tea lacking suppressiveness, did not contain adequate fungi, or fungal activity, and lacked the protozoa needed.
While exactly the same amount of tea (or water, or fungicide on the control and fungicide-treated plants) was sprayed on all
plants, Tea One did not have an adequate microbial population to protect the plant surface.
Plate methods could not differentiate between the two teas.
TSA incubated at room temperature, in aerobic conditions, measures “aerobic
heterotrophs”. There was no detectable difference between the two teas using plate methods, despite the fact that Tea
Two was capable of suppressing blight, while Tea One, sprayed at the same concentration, in the same conditions, did not suppress
King’s B medium selects for pseudomonads,
but not all these bacterial species are beneficial to plants. Enumeration indicated that there were more pseudomonads in the
not-suppressive tea. Plate methods cannot distinguish whether the bacteria growing on this plate, and thus presumably pseudomonads,
will be beneficial to the plant. If these values were used to measure “species richness-diversity”, the not-suppressive
tea would get a higher “index” score than the tea that resulted in the plants remaining alive and producing a
bumper crop of tomato later in the year.
Please note that
“species richness-diversity” is not a valid name for any ecologically accepted measure of diversity. The lab that
developed and uses this index will NOT explain how this index is calculated, and will not show any data that documents what
relationship the index has with plant health. They claim the index is in any introductory textbook, but in fact, no textbook
anywhere has a measure called species richness-diversity. Until such time as the lab using this index documents the claim
that a higher index value actually means a benefit to the plant, the use of this index must remain highly questionable.
Spore-formers are determined by boiling the material in question to kill vegetative
cells, followed by plating the material on TSA. Only spores or highly dormant stages of organisms survive boiling. Those spores
capable of growing on TSA, at room temperature, in the particular oxygen conditions present in the plate (please recognize
that oxygen exchange is reduced by the fact that the plates are covered), are then enumerated. Again, the not-suppressive
tea had higher plate enumeration values. What is the relationship between what will grow on a plate, and physiological functions
occurring in the soil, or on plant surfaces? These data show that there is no relationship.
Direct determinations separate bacteria from fungi. Plate media do not separate even bacteria
from fungi, much less not giving an indication of what is going on with approximately 99.9% of the species present in the
Direct determinations also let you know
whether protozoa or nematodes are present and performing their functions. A much clearer picture of what biology is present
and performing their functions is possible when using direct determinations. Direct methods let you know if coverage on leaf
surfaces is adequate. These types of assessments need to have a clear relation back to benefit to the plant.
Please note that there is no consistent relationship between plate count enumerations
of “species richness-diversity” and improvement in plant growth. Plate counts do not assess diversity or activity
of the organisms in the test material. An insignificant number of the actual total individuals or total species present in
a sample grow on any single plate medium or set of lab conditions that it is difficult to see why anyone would continue to
pretend that there is a relationship between plant growth and plate count assessments of diversity.
| ||Tea lacking Suppressiveness||Tea Capable of
|Plate Methods (MPN)
|TSA||1.6 (0.5) X 108||1.6 (0.7) X 108|
|King's B||5.0 (1.4) X 103||1.2 (0.2) X 103|
|Cellulose||35 (12)||210 (43)|
|Spore-formers||7.9 (0.4) X 102||0.3 (0.1) X 102|
(ug per ml)|
|Active Bacteria||8.0 (2.6)||12.7|
|Total Bacteria||25.1 (1.0)||245|
|Active Fungi||0.00||3.76 (1.00)|
|Total Fungi||0.35 (0.12)||11.1 (2.33)|
|Direct Microscopy (numbers per ml)|
|Flagellates||17 (10)||110 (34)|
|Amoebae||124 (59)||1,801 (1,112)|
|Nematodes||0||0.35 (0.05) |
|Leaf Coverage (%)|
|Bacterial||27 (4.7)||86.9 (9.7)|
|(5 plants)||All plants||15% showed blight
| ||diseased, all dies||None died|
|SD = Standard deviation of the mean|
C. 5. Compost Tea Standards
Desired levels of organisms (direct microscopy) in compost tea
- 10 to
150 or more µg active bacteria /ml compost tea
- 150 µg to 300 or more µg total bacteria
/ml compost tea
15,000 - 25,000 or more bacterial species (using molecular methods)
- 2 to
10 µg or more active fungi /ml compost tea
- 5 to 20 or more µg total fungal biomass/ml
5,000 to 8,000 or more fungal species (using molecular methods)
- 2,000 or more protozoa
1,000 or more flagellates
1,000 or more amoebae
10 – 30 ciliates. Higher numbers indicate anaerobic
conditions resulting from organism in tea growing so fast that oxygen is consumed
- 2 to 10 BENEFICIAL
nematodes/ ml (desired; typically lacking in tea)
1 - 5 bacterial-feeders
up to 5 fungal-feeders
1 - 5 predatory
nematodes (typically lacking in tea)
No root-feeding nematodes
- Minimum of 10% active bacteria
With biology at or above these minimal
ranges (more is better), this tea should result in improving foliar or soil life significantly, as long as pesticides, pollutants
and dust are not a problem.
Application of a tea containing
this set of organisms should result in a minimum of 65% of the leaf surfaces covered with bacterial biomass, and 5% with fungal
biomass. In trial after trial, we have shown that with this minimum level of coverage, the leaf surface is protected, through
a variety of mechanisms, from colonization by pathogenic organisms.
Compost Tea Standard Conditions
rumors flying out there suggest that someone is saying that there are no standard conditions for tea production, but in fact
standard conditions are necessary in tea production.
order to make consistent compost tea, the starting conditions must be t he same, and the same conditions must be maintained
during the brewing.
We manage to routinely make teas with
the same bacteria, fungal, protozoa and nematodes biomass and numbers present, time after time. But if you want something
with a different set of organisms, or different levels of organisms, change the foods, the temperature of brewing, aeration,
or water conditions. Maintaining the same conditions allow the same brew to be made over and over. Changing conditions allows
a different tea to be made. Like making cake, or beer, biology responds to what you put into the starting mix and how you
treat the material during the brewing, or cooking, process.
- room temperature water to begin,
- no chlorine (aerate
- neutral water (pH 6.5 to 7.5),
- oxygen maintained above
6 ppm through the entire brewing cycle, and
- good aerobic compost (per gram dry weight of compost)
containing at least:
The list of papers specific
to compost tea and compost have been summarized by Steve Diver, and are listed on the ATTRA website, www.ATTRA.org
Habitat requirements for beneficial bacteria
and fungi required to prevent pests and pathogens
- Maintain 5.5 ppm O2 or higher during brewing cycle
- Pleasant Smell
- Increase in temperature of 1 to 10 F is normal
is typically sign of good bacterial metabolite development
- Maintain tea fully aerated as long
as held before use
For new (untested) tea making machine:
quality (outlined above)
- Starting recipe of the tea
- Temperature, oxygen
concentrations through the tea cycle
- Color of tea, foam, smell
- Chemistry and Pathogen
testing must meet local standards (city, county, state, Federal).
- Organism assessments must be
performed on three batches of tea
- Duration of the tests are 32 hours or until the growth of organisms
in the tea is completed. This establishes the brewing cycle; extraction, growth, expected increase in organisms, duration
of the tea cycle, when tea is ready to be used and whether the machine can hold tea for any length of time.
For existing machines with the above data available from the manufacturer:
of tea maker used,
- Compost quality
- Starting recipe of the tea
oxygen concentration, and CO2 or O2 data through the cycle must be submitted for each of the first three batches of compost
- Chemistry and Pathogen testing must meet local standards (city, county, state, Federal).
three batches of tea must show three consistent sets of organisms produced at or above levels given above
initial testing passed, each batch test each 3 months, or each set of different starting materials.
Sampling requirements for healthy foodweb assessment
end of desired brew cycle (depends on machine), measure temperature and CO2 or O2
- With the tea maker
still circulating the tea, take at least 5 different 1 to 2 ounce or 30 to 60 ml samples and place them in a clean plastic
8 to 12 oz (100 to 500 ml) plastic bottle with sealable lid.
- Put the lid on the bottle, mix by
shaking. If after mixing, the sample bottle is more than _ full, drain to halfway mark to allow airspace. The bottle should
contain at least 125 ml (4 oz) of tea.
- Send overnight to SFI lab. Send with completely filled
out sample submission form
C. 6. Tea Definitions
- brewed water extract of compost,
- contains all the soluble nutrients that were in
- production methods include completely aerobic (AACT), using fermentative selective
conditions (FCT), using long term brewing conditions where the tea returns to aerobic conditions after several weeks, as the
smell goes away (LBCT), or using truly anaerobic conditions (NACT).
- A true compost tea should contain
ALL of the organisms that are present in the compost. Loss of the aerobic groups when FCT, LBCT or NACT are made leaves it
questionable whether these products should even be called compost tea. They lack a large component of the biology needed to
obtain the benefits that are possible from compost or compost tea.
- the organisms in the tea are put-to-sleep using
a long-brewing time, or through use of a chemical that makes the organisms minimize activity. Unfortunately, the putting-to-sleep
process invariably kills many, many species. When we have documented these processes, in general, species diversity is reduced
by 50% during the putting-to-sleep process.
- SFI has worked with a recent process where organism diversity
has not been impacted, so it may be possible to not have reductions occur
- no brewing time water extract of
compost. This is just the organisms, as is, from the compost. No growing time allowed.
- Soluble nutrients,
enzymes, hormones and plant growth compounds are very much present. It does not take long for the enzymes, hormones or plant
growth compounds to be taken up and consumed by bacteria or fungi in these materials, however.
- extraction of the organisms
is minimal, so that this material is almost strictly the soluble nutrients that were in the compost. Because of the minimal
amount of biology in this material, these enzymes, proteins, hormones and other materials do not disappear as rapidly as in
a compost extract.
is not involved. May have good organisms present in the tea, if beneficials were present on t he plant surfaces.
- compost is not involved.
Typically a concern will be present about human pathogen load present in the material. Some documentation says that adequate
aeration, WITH the right biology and activity of that biological compoenent, can reduce the human pathogen load. More testing
- Manure teas should not be used on human foodstuffs any sooner than 90 to 120 days
C. 7. Tea Application Approaches Foliar sprays
- 5 gallons per ac (25 L per HA) for each 6 foot of canopy
- 20 gal per ac (100 L/ HA) each spring and fall,
- Or combine with compost application in the fall, tea soil drench in the spring
- spray into seed surfaces in a light mist, not even enough to wet the seeds
- roll seed or seed piece in solution
- place a drench of tea below seed as
planting in furrow
Caution: A tea high in sugar, high in carbon can set back
plants. A little amount often is the answer, not a big dose and walk away. High sugar may mean bacteria and fungi grow fast,
and since bacteria and fungi win in competition with plant roots for N, P, S, etc., the plant may end up being stunted.High bacterial densities can overwhelm
the leaf surface with high CO2 levels, keeping stomates open too long.
- remove soil core and spray tea into the aeration hole
- re-fill the aeration core with compost – compost
tea - sand mix
C. 8. Programs for Converting to Biological Farming
C. 8. Programs
for Converting to Biological Farming
from Chemical Intensive Practices to Sustainable Practices:
"How to's" of corn, wheat and soybean systems in
Dr. Ingham is happy to discuss these scenarios
by e-mail with people, and alter these specific approaches to fit their particular systems.
Yield goal 100 bu/ac
goal equal or higher
Soil chem test in August
Soil chem and biology
test in August
Prior to plant, 50 lbs NH3 (late Aug)
Prior to planting, compost or compost tea application at 10 to 15 gal per acre (check tea to make sure organisms
Planting – Sept 15
1.5 bu/ac seed, 10 inch drill spacing
Roll seed in compost tea and mycorrhizal spores to promote rapid germination
at planting, 10-34-0 at 30 to 40 lbs/ac
In first transition year, the same amount,
but second year, reduce by 30%, third year, drop again by 30%, then check soil chemistry and soil biology
40 to 50 lb N, 5 lb S, Herbicide through irrigation or Floater
Compost tea application,
add N,P,K through tea application IF needed (first year usually 30% less fertilizer required, second year usually drops even
more, may not be required. See below for herbicide replacement
If rust, insect problems, apply compost tea to deal with problem, in irrigation water
Weeds: Purselane can be used as a very short-canopy cover crop to maintain biology, maintain root mat
to choke out other weeds, but senesces or goes-to-sleep when moisture is limiting. Mustards are only a problem if the soil
is too bacterial indication is to add more fungal foods, typically as a fungal compost in the fall. Downy brome indicates
a soil chemistry imbalance, need to get Ca:Mg ratio corrected, need to have soil fungi improved. Goat grass- don't know this
one, would have to get some experience.
Make certain the organisms to suppress
and prevent wire worm, cut worm (Heterorhabditus) is present in the compost and in the compost tea. Stem maggot I need
to know more about the life cycle of this pest, but there is a bacterium and several fungi used to kill the larvae and eggs
in the soil. Green aphids can be suppressed through use of the compost tea, with particular Bacillus bacteria added to the
Yield goal 200 bu/ac
Same or higher, reduced inputs
Soil chemistry in Dec
Soil chemistry and biology tests in October
Use compost or compost tea to add the biology required
to have stalks decompose by next spring
March chop stalks
Usually not required
April 1 disc or chisel field
Usually not required; if needed, then
Perform, but soil usually so mellow this is not required
Apply 180 lbs/ac NH3 usually as anhydrous
In first year this may be
necessary, but apply as compost or compost tea, or as dry fertilizer; anhydrous kills the biology you are trying to build
2 weeks, groom with cultivator
Perform if necessary but within 1 to 2 year not
April 20, planting starts
Starter fertilizer 8-20-5.5, 40 lbs
P, 15 lbs S, 1 lb Zn, 15 gal app
In the first year, perform as usual. But
also roll seed in tea. Place VAM spores in planting row just under seed. Once VAM
established, P, S, Zn additions should
be reduced each year until shown not needed
Herbicide program, add N with Herbicide, 20 to 30 lbs
Apply corn gluten, sugar (molasses) if weed problem develops, see below for specific approaches. Compost
tea for fertility additions as required
Watering as plant emerges, as weeds need work
Water need reduces typically by 10% in first year, up to 50% in succeeding years.
In the first year, may still be required until Soil chemistry and biology is balanced
Weeds: Foxtail indicates a lack of available Fe. Need VAM on roots to have plants obtain needed Fe and
out-compete the foxtail. Kosha, sand burr both typically inappropriate balance of bacteria allows them to outcompete corn.
Return to a 1:1 ratio of fungi to bacteria. Thistle indicates high nitrate levels, so need to drop nitrate additions and use
molasses or corn gluten to remove excess nitrate, into the bacterial biomass. Then need to check balance on the protozoa and
nematodes. Protozoan inoculum, compost or compost tea may be needed.
wireworm both need the correct nematode present, which is typically in good compost. Spider mite and corn borer can be suppressed
with the right fungal inocula added in the compost or compost tea. Root-knot nematode needs to be combated by getting VAM
fungi on roots, improving the beneficial nematodes in the soil, and improving the beneficial fungal biomass.
Yield goal 60 bu/ac
or higher, reduced inputs
Soil chemistry in Dec
chemistry and biology tests in October
Use compost or compost tea to add the biology required to have plant residues
decompose by next spring
Field prep in April
Usually not required; if needed, then perform, but soil usually so mellow this is not required
1 planting starts
Apply 20-30 lbs/ac P Starter 8-25-5-0.5 at rate of 15 lb/ac Drill seed, 10 inch spacing
In first year this may be necessary, but as soils build, reductions in needed amounts will occur. Typically
want to apply Rhizobium and VAM in same application
Apply round-up third week May, third Week
As soil chemistry and biology improves, weeds are outcompeted by
the crop plant
In 2 weeks, groom with cultivator
Perform if necessary
but within 1 to 2 year not usually necessary
Bloom apply 50 lbs N through Irrigation
If the Rhizobium inoculum was ineffective, this may be needed, but once both the VAM and nodules
are no longer killed through use of herbicides, this will not be needed
Watering until harvest
If pests, diseases, add compost tea to the Irrigation water
Pigweed, grasses, foxtail. Reduce nitrate levels in the soil by adding corn gluten, molasses, or other bacterial foods to
tie up excess N. Get VAM back into soil, pigweed will be outcompeted by the beans. Grasses outcompete by balancing equal
fug to bacteria.
Insects: Bean leaf beetle, painted lady butterfly. Certain
species of bacillus bacteria on the leaf surfaces, applied with the compost tea should retard the beetle. Possibly the caterpillar,
but need to study this as we haven't encountered this previously on soybean.
C. 9. USGS Maximum Dissolved Oxygen in Water table
DO - % saturation
Oxygen saturation is calculated as the percentage of dissolved O2 concentration relative to
that when completely saturated at the temperature of the measurement depth. Recall that as temperature increases, the concentration
at 100% saturation decreases. The elevation of the lake, the barometric pressure, and the salinity of the water also affect
this saturation value but to a lesser extent. In most lakes, the effect of dissolved solutes (salinity) is negligible; but
the elevation effect due to decreased partial pressure of oxygen in the atmosphere as you go up (recall the breathing difficulties
faced by Mt. Everest climbers) is about 4% per 300 meters (1000 feet). The DO concentration for 100% air saturated water at
sea level is 8.6 mg O2/L at 25°C (77°F) and increases to 14.6 mg O2/L at 0°C.
Table 6.2–6. Solubility of oxygen in water at various temperatures
and pressures [From R.F. Weiss (1970). Temp °C, temperature in degrees Celsius; atmospheric pressures from 695 to 600
millimeters mercury begin after 40°C] (PDF) link to table