[Terrapreta] Soils, sugars and nutrient elements-response

[Janice Thies]

Dear Kevin,

I can address some of these questions for you and clarify a few misconceptions.

First, plants do not gain their energy from the soil.  They 
photosynthesize, meaning they use energy from the sun to make reduced 
carbon compounds (such as sugars) necessary for growth, development, 
reproduction and metabolism from carbon dioxide.  This does not mean 
that they do not respire, they do.  They use the organic C compounds 
(sugars) they produce via photosynthesis to generate cellular energy 
for other metabolic processes.  So, where you comment that the plants 
are getting energy by feeding sugar to the soil - this is not the case at all.

Instead, what is likely happening is that soil heterotrophic 
organisms (decomposers) are using the sugars themselves for 
energy.  Where there is abundant energy (carbon compounds, such as 
sugars) and abundant mineral nutrients (such as N, P, K, Mg, S, etc), 
the mineral nutrient elements will increase in concentration in the 
soil solution as they are in excess of the cellular needs of the 
microbes.  Hence, more of these nutrients are available for plant 
uptake (because they do take these up from the soil solution). Where 
there is abundant energy and mineral nutrient elements are scarce, 
then they will likely be "immobilized" in microbial biomass and NOT 
available to plants.  This is the explanation for the 'robbing N from 
plants' part of your question.

On in place composting, you need to be careful of a few things.  The 
pH of the materials incoming, their C:N ratio, salt concentrations 
and how much of a good thing there is come to mind immediately.  One 
hallmark of composting is the thermogenic stage, where the pile heats 
up.  This can help begin the decomposition of more recalcitrant 
materials, but can - if happening in place - burn your plants 
literally.  If urea is present in high amounts, this can cause 
another kind of leaf 'burning' to take place.  If the pH of the 
material is too high, N may be lost an ammonia to the atmosphere, if 
the pH is too low, plant roots will be very unhappy.  If the C 
content is very high, then N will be immobilized, if it is very low, 
then it is likely to be very actively degraded and localized heating 
can be expected.  Salts can also be a problem if the materials are 
not mixed to dilute them with the surface soil or other organic 
materials that are low in salt content.  So, know your materials is 
the best bet.  Understand how they will behave as they decompose in 
place and be sure that you do not inadvertently harm the system while 
trying to preserve the nutrient content to feed the soil, rather than 
be lost to the atmosphere.


At 10:16 AM 4/19/2007, you wrote:
>Dear AD
>
>Wow!! With your different approach to Problem Solving, it is easy to 
>see why you win Ashden Awards!!
>
>I an an ignorant amateur gardener, amazed by Mother Nature. I 
>started off as a great fan of "Chemical Agriculture", as promoted by 
>the multi-national fertilizer companies. Then I swung over to "Feed the
>Soil, and it will feed the Plant." One of the key beliefs in 
>so-called "Organic Agriculture" is that one must compost the organic 
>additions before adding to the soil, because if the "raw" organic material
>composts in place, it will rob Nitrogen from the plants.
>
>On the other hand, composting "in place" does end up with more "in 
>place energy availability". The first question is: Is this potential 
>energy available to the plant, or does it simply get consumed by the "in-place
>composting bacteria", with no direct benefit to the plant?  the latter
>
>The next question is: It there any way to prevent the "in-place 
>composting process" from temporarily depleting the Nitrogen that 
>would otherwise have been available for plant growth? yes, by 
>keeping the C:N ratio overall not too much higher than 20:1, which 
>is the theoretical tipping point between N immobilization and N mineralization.
>
>One obvious solution to the Nitrogen Availability problem might be 
>to ensure the raw materials had adequate Nitrogen to permit "self 
>composting" ingredients to compost in-place, without the need for 
>temporarily robbing Nitrogen from the plant.  Indeed  However, all 
>that this might accomplish would be a "self fueled fire". The 
>ingredients would have no need to interact with the Soil, and rob 
>its nitrogen.  Not sure what you mean here
>
>On the other hand, your "Sugar Fertilizer" procedure seems to work 
>wonderfully, and no Nitrogen is added to the Soil... only energy for 
>the plants.  This is not energy for the plants as explained above
>
>Is it perhaps a case of "too much of a good thing is a bad thing?" 
>One can see that too much cellulostic plant material with a high C/N 
>ratio added to the soil could possibly deplete N from plants, but if a smaller
>amount was added, there might not be enough cellulose to deplete 
>existing soil N to retard plant growth over the short term.  Indeed
>
>So we seem to get back to the first question: Could you please 
>explain how the release of energy from "in-place composting" is more 
>beneficial to the "Soil Food Web" than would be the addition of the 
>same material
>that was composted externally?  The answer lies in doing 'in place 
>composting' correctly, aiming to not lose your N (and S) to the 
>atmosphere, but keeping it in organic forms, such as living 
>microbial biomass that is recycled on a short time scale.

Hope this helps.

Janice


>Thanks!!
>
>Kevin Chisholm
>
>adkarve wrote:
> > Dear Juergen,
> > Do not apply compost to the soil.  On the one hand, agronomists tell us to
> > apply organic matter to the soil in order to feed  the soil 
> micro-organisms,
> > but on the other hand, they ask us to compost the biomass before 
> applying it
> > to the soil. The nutritional value of the biomass is lost in the process of
> > composting. Also, while recommending the dose of compost to be applied,
> > agronomists calculate it according to the N.P and K content of the compost
> > and not according to the nutritional calories in the compost. We found in
> > our experiments that non-composted green leaves, applied at the rate of 125
> > kg per ha, once every 2 to 3 months, gives as high yield from crops as
> > application of recommended doses of chemical fertilizers.  Even in the case
> > of dung, we found that relatively small quantities of dung are highly
> > effective, if the dung is applied in the raw and non-composted form.  Dung
> > consists partly of lignin (which can be digested neither by herbivorous
> > animals nor by the anaerobic bacteria in their guts) and partly of a large
> > number of bacteria. Both the lignin and the dung bacteria serve as food for
> > the soil bacteria. By composting dung, we unnecessarily rob the soil
> > micro-organisms of nutrition.
> > Yours
> > A.D.Karve
> >
> > ----- Original Message -----
> > From: Juergen Botz <jurgen at botz.org>
> > To: <terrapreta at bioenergylists.org>
> > Sent: Wednesday, April 18, 2007 5:45 PM
> > Subject: [Terrapreta] Greetings
> >
> >
> >> Hello, all.  I just joined the list, glad to see it so lively!
> >>
> >> To introduce myself... about a year ago I acquired a small farm
> >> in coastal Bahia, Brazil.
> >>
> >> The land is 2/3 secondary growth Atlantic rain forest, the other
> >> 1/3 is partially planted with coconut palms and pineapple, plus
> >> various fruits and plenty of manioca.  Unplanted areas that
> >> aren't forest are heavily overgrown with dense brush.  The
> >> subsoil is nutrient-poor loam, often highly compacted.  In most
> >> spots there's a layer of anywhere from an inch to a foot that
> >> has a significant amount of organic matter, and yes, quite a bit
> >> of charcoal.
> >>
> >> The charcoal doesn't seem to have been deliberately incorporated...
> >> rather, the area has been cleared by fire a couple of times in
> >> the past and because of the high humidity here that leaves a
> >> lot of charred matter.
> >>
> >> I am experimenting with various natural farming and permaculture
> >> techniques here, and my main goal right now is to get the soil
> >> in better shape.  That means breaking up the compacted subsoil,
> >> adding organic matter, adding more charcoal to stabilize it and
> >> reduce future compaction, planting various leguminous trees and
> >> ground covers, and of course building up a layer of humus.
> >>
> >> I have a source of humus and wood for charcoal in the forest.
> >> I've also been making large quantities of compost from a mixture
> >> of wood- chips, manure, and seaweeds raked up at the beach.  I'm
> >> thinking of adding charcoal to this mix right from the start of
> >> composting.
> >>
> >> One of the things that led me to this list was that I was
> >> scouring the Net for info on small-scale charcoal production.
> >> I found a bunch, and I found this list.  I think I'll be trying
> >> some pit-kiln variation shortly, and in the longer run I may
> >> build something like the adam retort.
> >>
> >> :j
> >>
> >>
> >> _______________________________________________
> >> Terrapreta mailing list
> >> Terrapreta at bioenergylists.org
> >> http://tech.groups.yahoo.com/group/biochar/
> >
> >
> > _______________________________________________
> > Terrapreta mailing list
> > Terrapreta at bioenergylists.org
> > http://tech.groups.yahoo.com/group/biochar/
> >
> >
>
>
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*****************************************************************
Janice E. Thies
Assoc. Professor of Soil Biology
Director of Graduate Studies
719 Bradfield Hall
Dept. of Crop and Soil Sciences
Cornell University
Ithaca, NY  14853

phone 607-255-5099
fax    607-255-8615 
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