Subject: Re: Till/noTill

From: Elaine Ingham <[email-masked]>
Date: Sat, 19 Apr 2003 12:52:30 -0400

Hi Gil!

Good to hear from you! Wish we would have had time to chat more at the meeting in Tulare.  I sure am interested in your microbial work, and wonder if you know of microbes specific for different conditions, especially sets of bacterial and fungal species specific for selecting against different weeds.

There are two ways to figure out the associations of different plants relative to Fungal to Bacterial ratios (F:B).  As you remember from my talk, the successional stage tells you some information about the F:B ratio.

For example, brassica belong in the early successional group of plants, at least based on everything we've looked at in the group.  This stage of successional plants are strongly bacterial dominated, in the range of 0.35 to 0.5

Solanaceae, or plants like tomato, potato, etc, are mid- successional annuals and grasses, in the mid-bacterial dominated range.  So ratios of 0.5 to 0.75

The earthy smell of soil is sometimes the result of the griseofulvins made by actinobacteria (used to be called acitnomycetes, but they are truly bacteria, and thus more correctly labeled actinobacteria).  Actinobacteria can be very inhibitory to mycorrhizal fungi.  We see that some soils are held in weed-field conditions because the soil gets so strongly actinobacterial that beneficial fungi cannot establish on the roots.  Thus succession gets "stuck" for awhile in the weed or early successional stage until the soil organisms can pull out of that actinobacterial soil dominance.

Other soil organisms also produce these compounds.  Other "earth-smells" are made by other organisms.  The mildew smell many people associate with soil is of course not a good thing.  The mildew smell indicates bad conditions, not good.

Rich, deep earth smells, as one detects in old-growth forests, is a fungal smell, typical of the basidiomycetes.  Since many of these beneficial species produce mushrooms, many people associate these good smells with prime mushroom-growing conditions.  That set of smells can be used as indicators of healthy soil.

You could just use this table to think about the F:B ratio

Plant Succession Stage   F:B

No plants                0.01
Weeds                    0.10
Brassica, Bromus
  Bermuda             0.30-0.50
Early grass,vegies    0.50-0.75
Late grass, row crops 0.75 to 1.2
Shrubs, perennial herbs  2 to 5
Deciduous trees          5 to 100
Conifer                50 to 1000

These ratios are based strictly on observation of thousands of soil samples.  The ratios pointed out here are from HEALTHY systems, where the plants do not require pesticides or inorganic fertilizer additions in order to grow.

As soon as pesticides and inorganic fertilizer additions are required, the soil is by definition not healthy with respect to that plant species.  It is healthy for some other plant species, such as a thistle, or a dandelion.  Or maybe the correct, healthy soil for a blackberry vine.

To know if the soil is fungal, you need to see the fungal strands in the soil.  We'll be putting up some pictures of good fungal strands in soil and compost on our website in the next month, so that everyone will know what I mean by strands of fungi instead of pouffy, fuzzy, grey to white fungal fluff.

Earthworms are a good indicator of a decent foodweb, excellent for the vegie and row crop stages.  If the worms get alot of brown leaf fall material, they will likely push the soil fungal.  So if you feed you worms the right stuff, they can maintain fungal biomass in the soil.  But then you won't likely see the fungal strands, you would have to send a soil sample in for analysis to know for certain.

Some growers take some of their soil, compost it, and make sure they have the right fungi present by allowing the soil to not be disturbed and then seeing the good fungi grow in thick white strands.  If no growth after a week, then they know an inoculum is needed, and that it is time to find some of those white fungal strands.

Find good fungal inocula in materials like Alaska Humus in the US (www.alaskahumus.com), or in the  Tryton Biostarter product, or a good fungal compost (see the SFI website for composts proven to have decent fungal compost, it is a rare thing to have decent fungi in most composts.  In fact most commercial compost around the world is not decent compost).  A healthy forest soil, from the duff layer is also a good place to get a good inoculum, but in the US, there are very few heatlhy forest soils left.  Be careful there!

Add those inocula to your special starter soil, maintained at human room temperatures, at 50% moisture, with additions of healthy fungal inocula whenever you see them.   Get your special starter soil into your compost or soil, or make a good fungal compost tea.

OK?  Make sense to you?

Elaine Ingham

> hi elaine!
> is there a way to find out what are the associations of vegetables of
> different families like brassicas and solanaceous?  are they fungal or
> bacterial?  and is there a way, naturally by simply observation that you
> will find out whether the balance in the soil foodweb?  like when we see the
> soil and smell earthy, it is more fungal in association, ya?  see poor
> farmers do have the dough for soil tests and things of that
> nature.  a
> working, guideline will be enough.
> gil carandang
> herbana farms
> philippines