compost teas
...(text from the book, "Teaming with Microbes" written by Jeff Lowenfels and Wayne Lewis)...any questions or comments about the book are welcome, I'd love to discuss it.
...+ REP if you like.
....the 19 rules!
1) Some plants prefer soils dominated by fungi; others prefer soils dominated by bacteria.
2) Most vegetables, annuals, and grasses prefer their nitrogen in nitrate form and do best in bacterially dominated soils.
3) Most trees, shrubs, and perennials prefer their nitrogen in ammonium form and do best in fungal dominated soils.
4) Compost can be used to inoculate beneficial microbes and life into soils around your yard and introduce, maintain, or alter the soil food web in a particular area.
5) Adding compost/ compost teas and its soil food web to the surface of soil will inoculate the soil with the same soil food web.
6) Aged, brown organic materials support fungi; fresh, green organic materials support bacteria.
7) Mulch laid on the surface tends to support fungi; mulch worked into the soil tends to support bacteria.
If you wet and grind mulch thoroughly, it speeds up bacterial colonization.
9) Coarse, dryer mulches support fungal activity.
10) Sugars help bacteria multiply and grow; kelp, humic and fulvic acids, and phosphate rock dusts help fungi grow.
11) By choosing the compost you begin with and what nutrients you add to it, you make teas that are heavily fungal, bacterially dominated, or balanced.
12) Compost teas are very sensitive to chlorine and preservatives in the brewing water and ingredients.
13) Applications of synthetic fertilizers kill off most or all of the soil food web microbes.
14) Stay away from additives that have high NPK numbers.
15) Follow any chemical spraying or soil drenching with an application of compost tea.
16) Most conifers and hardwood trees (birch, oak, beech, and hickory) form mycorrhizae with ectomycorrhizal fungi.
17) Most vegetables, annuals, grasses, shrubs, softwood trees, and perennials form mycorrhizae with endomycorrhizal fungi.
1 Rototilling and excessive soil disturbance destroy or severely damage the soil food web.
19) Always mix endomycorrhizal fungi with the seeds of annuals and vegetables at planting time or apply them to roots at transplanting time.
Compost Tea---- Compost tea puts the microbiology back into soils. It's a good thing because there's some practical problems associated with the other 2 options, compost and mulches. Besides the effort of turning a compost pile, if you have a decent-sized garden and lots of trees and shrubs, carting compost and mulches around and applying them can be hard work. You also have to have lots and lots of both if you are working on anything but a small yard. But what are the chief problems with compost and mulches? They take a while to reach the rhizosphere. And neither mulch nor compost sticks to leaves. Plants generate exudates from their leaves, attracting bacteria and fungi to the phyllosphere, the area immediately around the leaf surfaces. As in the rhizosphere, these microbes compete with pathogens for space and food and in some cases can protect the leaf surfaces from attack. You cannot immediately introduce this microbiology into the rhizosphere, or into the phyllosphere at all, with compost or mulch.
Actively aerated compost teas, on the other hand, are usually easy to apply---both soil and leaf surfaces---and are put right where they are needed. They are a fast, inexpensive, and definitely fascinating way to manage soil food web microbiology in your yard and gardens, handily overcoming the limitations of compost and mulch.
What AACT is not
Do not confuse actively aerated compost tea with compost leachates, compost extracts, or manure teas, all of which have been employed by farmers and gardeners for centuries.
Compost leachate is the liquid that oozes out of compost when it is pressed or when water runs through it and leaches out. Sure, these concoctions get a bit of color and may have some nutrient value, but leachates do little to impart microbial life to your soils: the bacteria and fungi in compost are attached to organic matter and soil particles with biological glues; they don't simply wash off.
Compost extract is what you get when you soak compost in water for a couple weeks or more. The end result is an anaerobic soup with perhaps a bit of aerobic activity on the surface. The loss of aerobic microbial diversity alone (not to mention the risk of it's containing anaerobic pathogens and alcohols) suggests that compost extracts are not worth the effort. We don't consider it safe or advisable to use them.
Manure tea, created by suspending a bag of manure in water for several weeks, is also anaerobic. Using manure is asking fro pathogenic problems and, especially under anaerobic conditions, virtually assures the presence of E.coli. We want the beneficial microbes to be working in our soils and to get these; you have to keep things aerobic.
Modern compost tea
Modern compost teas, on the other hand, are aerobic mixtures. If the tea is properly made it is a concentrate of beneficial, aerobic microbes. The bacterial population, for example, grows from 1 billion in a teaspoon of compost to 4 billion a teaspoon of an actively aerated compost tea. These teas are made by adding compost (and some extra nutrients to feed its microbes) to dechlorinated water and aerating the mix for one or two days. It is this mixing, or active aeration that brings old-fashioned anaerobic compost teas into the modern era; it is also what keeps these compost teas aerobic, and thus safe. The air supply must be sufficient to keep the tea aerobic throughout the entire process.
It takes energy to separate microbes from compost. You know how much energy you have to use daily (or should) to remove another form of bacterial slim: plaque on your teeth. Bacterial slime in soils is just as strong. Consider, as well, that fungal hyphae grow not only on the surface of compost crumb but inside its nooks and crannies; you have to use energy to pull these strands off and out in addition to getting the bacteria "unglued." Of course, too much energetic action can kill these microbes. A brewer's action must be strong enough to tease out the microbes but not so strong that the microbes are killed once they are out of the compost and into the tea.