[compost_tea] Letter to the Editor

From: kevin john richardon <kmagic_at_backpacker.com>
Date: 20 Jun 2003 12:22:40 -0000

Hello Friends,

Please take time to consider the following, brief article which appeared yesterday, Thursday, June 19, in the Anchorage Daily News:

Quality counts with compost tea


By SUE LINCOLN
Daily News correspondent

(Published: June 19, 2003)
The Cooperative Extension Service horticulture office receives many inquiries about compost tea -- how to make it, the benefits and if it really works. To answer these questions, one must have some knowledge of plant/soil interactions.

Soil is a very complex community consisting of millions of microscopic living organisms and decaying organic material. Soil scientists define soil as a combination of three particles varying widely in size and chemical reactivity: sand, silt and clay, plus organic matter. Plant nutrient availability depends on the structure and texture of a soil as well as microbial activity. Texture depends on the percentage of sand, silt and clay in the soil.

A soil that is high in sand has large particles and large pore spaces where water and nutrients can flow through and beyond the reach of the root system. Because of the large particles consisting mainly of silicon dioxide and the lack of clay particles, chemical ions in soil solution are not attracted to the sand particles and tend to move with soil water.

Soils high in silt have smaller particles than sand and smaller pore spaces for water and gas exchange. Silty soils tend to release nutrient ions into soil solution with time and are often highly productive.

A soil that is high in clay has very small particles and very small pore spaces allowing ions to be held tightly to their surface but not allowing water and air permeability, resulting in a struggling microbe population and poor aeration. Although soils high in clay are considered to have high cation-exchange capacity (the chemical reaction in the soil), which is desirous for plants, the particles are so small and tightly packed together it is difficult for root growth, gas exchange for microbial activity and diffusion of nutrients to the root surface.

The addition of organic material such as compost is beneficial to soil structure and adds to the total cation-exchange capacity of the soil. The added organic material increases moisture retention and helps to increase microbial populations. Microbes break down organic particles into chemical components usable to plants. This microbial action enables the nutrients to be available for plant roots to absorb.

COMPOST and COMPOST TEA

Compost is the result of plant material that has been decomposed by soil microbes to a soil-like state -- although it is not soil. In general, the benefits of adding compost to soil are many. However, the quality of the compost is important. In order to achieve good quality compost, steps must be taken to use quality ingredients, maintain temperature and moisture and ensure good air circulation throughout the composting process. These steps also must be taken for a quality compost tea. The compost tea will only be as good as the compost used.

Compost tea is the leachate of compost where water is added to extract nutrients and microbes. The tea consists of a very large and diverse microbial community. Some recipes include the addition of carbohydrates such as yeast, molasses or other sugars to encourage microbe reproduction.

There are basically two types of compost tea: anaerobic and aerobic.

For the anaerobic method, the compost is allowed to sit in water for several days. By allowing the water to sit undisturbed, the anaerobic-microbe population increases while the microbes that prefer an oxygenated environment decline.

In the aerobic method, air is pumped through the solution thereby increasing the aerobic-microbe population within the solution. Depending on what the compost tea will be used for will determine which method is used.

TWO WAYS TO USE TEA

There are basically two uses for compost tea. One is to increase microbe populations in the soil so they can break down and release nutrients to be available to plants. The other is a foliar spray used for nutrient application as well as a fungicide.

There is quite a controversy over the claimed benefits of compost tea. The scientific community is just beginning to conduct controlled studies on how the soil community and plants respond to the addition of compost tea. There is consensus, though, that compost tea added to the soil does add to the microbe population, thus enhancing the probability of increasing soil fertility by microbial release of nutrients. However, the use of compost tea as a foliar fungicide has brought the largest controversy.

There have been several controlled experimental studies using compost tea as a fungicide on specific pathogens and crops. Results have been conflicting. However, some results suggest that compost tea brewed using the anaerobic method may be more effective as a disease suppressive than compost tea brewed using the aerobic method. In other studies, foliar application of compost tea encouraged pathogen growth.

USDA CONCERNS

The U.S. Department of Agriculture has documented concern over using compost tea as a foliar spray. Pathogens such as E. coli and Samonella have been cultured from the tea when carbohydrates were added to the brew. One experiment suggested that by not adding the carbohydrates, E. coli could be eliminated even though the pathogen was present in the compost prior to brewing the tea. In addition to the concern of dangerous pathogens, foliar applications of compost tea can be high in salts, which can burn tender foliage. This is another case for the use of quality compost materials.

There is also controversy on the use of compost tea in organic farming. Because dangerous pathogens reproduce between the temperatures of 40 and 140 degrees, compost would need to heat to at least 150 degrees to kill all the pathogens. Prior to using animal manure, the National Organic Standards Board requires the material to be heated in excess of 150 degrees for a minimum of one hour and dried to a moisture level of 12 percent or less. Unfortunately, if the compost was heated to this high temperature all the good microbes would be killed as well. The Agriculture Marketing Service of the USDA recommends that if compost tea is used as a foliar spray on edible crops, harvest should not take place less than 120 days after application unless the compost tea is made without the addition of carbohydrates.

In order to keep healthy while consuming homegrown, organically produced food using compost tea as an amendment, use quality ingredients when building the compost heap. When the compost is finished, refrain from adding additional carbohydrates to the brew if foliar applications will be made.

Sue Lincoln is a horticulture program assistant with the University of Alaska Fairbanks Cooperate Extension Service. She is located in the Anchorage office. Contact her at 786-6315.

The Anchorage Daily News

Hmmm... I feel compelled to respond to a few items. Please let me know what YOU think. Promptness will be an issue as I would like to submitt a version of the following, Letter to the Editor:

Local Solutions
19025 Villages Scenic Pkwy
Anchorage, Alaska 99516
(907) 522-0679 907) 317-8455

Thursday, June 19, 2003

Letter to the Editor
Anchorage Daily News

Quali-tea results with Compost Tea

Wow, Sue Lincoln grabbed my attention!

Leading with such a concise yet informed portrayal of soil dynamics, I was anxious to read further. Turning the page, I expected what followed to champion the necessity of securing a quality source of compost to brew quality compost tea with… I finished the column feeling my understanding of Compost Tea conflicted and doubting Ms. Lincoln’s compilation of facts.

In all fairness, I assume responsibility for taking the initiative to seek out more information to better and verify my own understanding, yet I also intend to encourage all of us to be diligent and accountable in the reporting of our research and development to productively advance the enormous potential of the emerging science of Compost Tea.

Please know Dr. Elaine Ingham and Soil Foodweb Inc., a renowned resource recognized as the foremost authority in the field of soil microbiology, is adamant that Anaerobic Leachates of Compost ARE NOT Compost Tea.

This may seem like semantics, Sue, yet…

The terminology, “Compost Tea”, refers to a watery extract of Compost, made by the addition of a determined amount of high quality compost and microbial foods to water which IS ALWAYS at least 5.7% Oxygen per Volume! This is important to agree upon.

As a general rule with exceptions, anaerobes produce substances which inhibit growth. We want to provide an environment which promotes the growth of aerobic microorganisms. These are the microbes whose interrelationships within their community have the desired, positive, beneficial effects on soil and plant characteristics we are attempting to cultivate with compost tea.

True Sue, “The compost tea will only be as good as the compost used.” Only organisms present in the brewing materials will be found in the Tea. The action alone of adding carbohydrates or any other nutrient will not result in the cultivation of pathogens.

I am not aware of Compost Tea having a Salt Index. As you mention, if foliage is being burnt by salts, this also would be a source issue.

Interestingly, Anchorage, Alaska has, to my understanding, one of the three known best sources of composted material on the planet. Certain types of Humus, commonly referred to as “peat”, posses the finest attributes of a composted material. The most important asset, Sue will agree, is that there are NO CONTAMINANTS. It is virgin material. Secondly, the number, type and diversity of species contained in the Humus is outstanding. The tests register impressive numbers. This resource is being actively conserved by a local group. Look them up at AlaskaHumus.com.

Facts have been gathered indicating foliar applications of Compost Tea achieving 70% leaf coverage or greater successfully suppress disease. 90% coverage, 7% of which is of beneficial fungal content, has achieved 100% protection! Yet this accomplishment is not likely achieved by secretions of toxins as “-icides” suggest. Rather the beneficial microbes present in Tea out-compete pathogens for space and food resources and in some cases predate on disease causing organisms.

Much of the wonderful feedback I receive from those who employ compost tea generates a foremost concern for quality. It is imperative we achieve accuracy in the dissemination of information, as public awareness and perception of Compost Tea is being developed during this growth stage in the industry and we want this science to move forward and realize maximum potential.

Please consider these remarks as we gain in our collective knowledge and ability to brew and apply Compost Tea. Thank you for your time and consideration.


Best Regards,

Kevin John Richardson


Your input is welcomed. Especially if I have errored in my facts, judgement, etc...

Please feel free to edit. Suggestions contrary to my current opinion are especially warrented. Please let me know if you think the gal wrote a decent peice and I should let it go. No reason to come off like a jerk, ya know?

Peace, Kev
ps sorry soo long

Kevin John Richardson
Local Solutions
19025 Villages Scenic Pkwy
Anchorage, AK 99516
(907) 522 0679 Land
auto forwards to :
(907) 317 8455 Cell
kmagic_at_backpacker.com



------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get A Free Psychic Reading! Your Online Answer To Life's Important Questions.
http://us.click.yahoo.com/Lj3uPC/Me7FAA/ySSFAA/0PSxlB/TM
---------------------------------------------------------------------~->

To unsubscribe from this group, send an email to:
compost_tea-unsubscribe_at_yahoogroups.com

 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/




Received on Fri Jun 20 2003 - 12:35:40 EDT

This archive was generated by hypermail 2.3.0 : Tue Feb 07 2012 - 14:29:20 EST