Re: [compost_tea] basic questions

From: <soilfoodweb_at_aol.com>
Date: Sun, 02 Jan 2005 10:37:58 -0500
Hi Butch -

Consider natural ecosystems in order to answer your question.  No one adds anything to those systems, but nature builds soil from sterile (all of the planet's surface was sterile before life started), to old growth forest, the richest soil on the planet.  Consider all of the successional stages in-between, where soil is being built.

Nature does not require any additions from outside the system in order to build soil.  Everything can come from within. 

What scale are we talking about, however.  Nature does not work on the scale of a single agricultural field.  Nature works on the scale of a watershed, at the very least.  The top of the mountain is going to take a great deal longer to become old growth soil than the riverbank. 

But, all the soil within that watershed was once dirt (sterile, or lacking adequate life to sustain plant growth).  That soil was built, by adding biology to do the work. 

The main work was, first, establishing the microorganisms, species by species, to establish nutrient cycling, nutrient retention, and build the ciomplex set of food resources within the soil so succession could occur. 

Photosynthetic organisms are part of the system, they fix sunlight energy into food for everyone else.  But long before plants arrive, photosynthetic bacteria, algae, etc fix energy and provide food for the microbes in the soil to do their soil-building. 

Plants require the right set of organisms to be already present in the soil to convert nutrients the plants require into the forms that the plant has to have.  Plants can't do that on their own. 

As you go through succession, plant species shift from one stage to the next based on the microorganisms in the soil (which required the previous stage of successional processes to be occuring, which required the right set of microbes, which required the previous sets of foods which means the previous set of plants..... and so on).  As foods change, and the microbes change, the rate and timing of nutrient release, and the dominant form of nutrients available change, then plant species shift. 

As you go through the entire course of sucession, the shift in the microbial world belowground is from one completely bacterial, to more, and more, and more fungal, until old growth forest soils are 1000 times more fungal than bacterial.  You want shrubs, then get the foods (plant debris) and the microbes (compost as inoculum) right for shrubs to be selected. 

You want to build your soil?  You need to put in the right foods (plant debris, but not just any old plant debris, you need to make it plant debris that will provide the right foods for the right microbes), and shift the organisms present to those that will build the stage of succession to what you want. 

Understanding WHICH species of bacteria and fungi are present at each stage is the next step of scientitific understanding that has to occur, and there are methodology problems we have yet to solve to be able to understand and measure that microbial diversity.  But we will do this. 

So when you ask if organic debris has to be present, most of us don't regard that as a question. 

Organic matter in the soil is required. 

To feed the microbes in the soil. 

Microbes make their own organic debris, and thus build soil all on their own, without higher plants.  Not a productive soil from a human point of view, but soil nonetheless. 

The plants which can grow in poor soil are limited to mainly what we would call weeds.  But weeds are important in adding in more foods, and thus building more organic matter in the soil, allowing more and different kinds of microbes to grow. 

As nutrient cycling changes, different plants can now germinate and grow.  We are at the next stage of succession.  Now, with the new foods appearing, new organisms can grow, alter nutrient retention and cycling in the soil, build soil structure so the soil is, eventually, more suited to the plants of the next stage of succession.  And so on, and on, and on, until you reach old growth conifer forest. 

All evidence on this planet points to conifer forests as being the "climax" community. 

But wait, not every bit of this planet is old growth forest.  Hasn't successsion been going on long enough that every place should be old growth?  What about the tops of mountains? 

Now you need to understand disturbance.  When a strong disturbing force occurs, be it tsunami, hurricane, fire, wind, bulldozers, flood, or chain saw, succession is reversed.  How far back does the system go?  Well, how much of the soil was destroyed?  How much of the reserve of organic matter was washed away?  Or burned? Or moved to another system? 

So, try thinking through this framework, and then maybe you will understand why the rest of us don't really get your question.  Of course organic debris will be present, plants are part of the system.  We can alter soil building processes by planting a different plant.  Or shifting bacterial and fungal ratios in the soil.  Organic material is food for the microbes.  What plant was it that you wanted to grow?  Feed the microbes needed to select for that plant. 

So, I probably haven't answered what you really wanted to know, but it's because I don't really comprehend what you are asking, I think.  The reason I don't get it is because we're coming from two different paradigms, and we have to modify the basic assumptions one or both of us are using before we can ask meaningful questions of each other. 

Time for a shift in the underlying assumptions. 

Not saying whose underlying assumptions have to shift here, ok?  Could be me, could be you.....nothing bad in shifting one's understanding of  the world, as long as we are both moving toward understanding the world in a more realistic manner.

Only way to test our understandings of reality is to talk to each other, in a way and manner that promote understanding. 

So, Butch, I really appreciate your efforts, because while you are frustrated that your question isn't being answered, you haven't descending into name-calling, attacks on others, or unpleasantness. 

Anyone else have some insight into Butch's question?  Am I missing something obvious? 

--
Elaine Ingham
President, Soil Foodweb Inc.
SFI Corvallis, OR
SFI Port Jefferson, NY
SFI Lismore, NSW, Australia
SFI Cambridge, New Zealand
SFI Culiacan, Mexico
SFI Jerome, Idaho
SFI South Africa
http://www.soilfoodweb.com



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Received on Sun Jan 02 2005 - 15:33:48 EST

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