[Digestion] Digestion Digest, Vol 2, Issue 31
adkarve at gmail.com
Sat Oct 16 05:07:03 PDT 2010
Dear Ivo and AD workers,
there is a lot of misunderstanding about effect of organic material on crop
yield. The textbooks say that plants cannot absorb the minerals in the soil,
because they are insoluble in water, and therefore one has to apply water
soluble chemicals in the form of fertilizers or organic composts to a field.
The textbooks also explain that one needs a high population of microbes in
the soil for decomposing the organic matter because it is the microbes
that make the minerals in the organic matter available to the plants. Both
the assumptions in the text books are wrong. Let me first of all point out
that water is a universal solvent, and that it dissolves all minerals in the
soil. Silica is present in the soil in the form of quartz, opal and various
silicate minerals. They are considered by the lay public to be insoluble in
water, but the capillary water in the soil contains from 5 to 15 p.p.m.
(parts per million or mg per litre of water) silica. That plants can take up
silica from the soil is dmonstrated by the fact that a single crop of wheat
or rice removes from the soil about 250 kg silica per ha. This is possible,
because the silica and all other minerals dissolved in the capillary water
in the soil, are in a dynamic equilibrium with the water. That means, that
molecules removed by plants from the soil solution, are replaced by new
ones contributed by the undissolved pool of minerals in the soil. Therefore,
in spite of the plants taking up the minerals from the
soil, the concentration of the minerals in the soil-water remains constant.
Once we accept the fact, that plants can take up minerals directly from the
soil, it can be shown that about 1 m thick layer of soil has enough minerals
in it to support agriculture without fertilizers for the next 25,000 years.
In semi-arid regions, farmers who depend solely on rainfall as the source of
water, never apply any fertilizers to their crops, because, if the rains
were to fail, they would lose all the money spent of fertilizers. In spite
of farming in this manner for thousands of years, they continue to get more
or less the same yield from their farms, year after year.
The next point that I wish to make is that micro-organisms are more
efficient than plants in absorbing the minerals from the soil, because they
absorb through their entire surface, whereas plants have only the root hairs
as the absorbing organs. If one provides the soil with pure sugar or an
organic acid, the microbes multiply their numbers, which is an indirect
proof that they can aborb minerals directly from the soil. When the source
of organic carbon is all eaten up, they die, releasing the minerals, now in
the forms of proteins, co-enzymes, etc. into the soil. These are then
absorbed by the plants.
The agricultural strategy based on this logic is to apply to the field a
relatively small quantity of high calorie substance instead of composted
material, from which the nutition has already been taken away. This high
calorie material causes the microbes in the soil to increase their numbers,
and as stated above, they make the minerals in the soil available to the
In fact, we are using the same strategy in our biogas technology. We use
food waste, having a high nutitional value as feedstock, instead of fecal
matter of animals, which has low nutritional value for the methanogens.
On Thu, Oct 14, 2010 at 6:18 AM, Ivo Oliveira <ivomdb at gmail.com> wrote:
> I've been reading a couple of documents about vermicompost and digester
> effluent aplication to different crops. For exemple: Vegetables (carrot,
> spinach, onions etc), Fruits and maize. For instance when applying digester
> effluent to vegetables 100 l per hectare (of a total 300 l mixed with water
> on a 1:3 ratio) should be added every 10 days. It seems quite small....
> However I found in other articles that you can apply raw digester effluent
> without dilution but doesn't say the amounts that should be added.
> Using Vermicompost the information seems more available but still not sure.
> For example I found that you can apply 120 g of vermicompost/ plant (crop)
> or 60 g or 10 g to vegetables.....
> So... the information available is some what diverse. I wonder if someone
> could share his knowledge when using digester effluent or vermicompost as an
> organic fertilizer.
> Ivo Oliveira
> On Wed, Oct 13, 2010 at 12:00 PM, <
> digestion-request at lists.bioenergylists.org> wrote:
>> Send Digestion mailing list submissions to
>> digestion at lists.bioenergylists.org
>> To subscribe or unsubscribe via the World Wide Web, visit
>> or, via email, send a message with subject or body 'help' to
>> digestion-request at lists.bioenergylists.org
>> You can reach the person managing the list at
>> digestion-owner at lists.bioenergylists.org
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Digestion digest..."
>> Today's Topics:
>> 1. Re: Digestion Digest, Vol 2, Issue 29 (David Fulford)
>> Message: 1
>> Date: Wed, 13 Oct 2010 11:21:31 +0100
>> From: David Fulford <davidf at kingdombio.com>
>> To: For Discussion of Anaerobic Digestion
>> <digestion at lists.bioenergylists.org>
>> Subject: Re: [Digestion] Digestion Digest, Vol 2, Issue 29
>> Message-ID: <4CB5882B.1040104 at kingdombio.com>
>> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>> Listers, Hi
>> The Ashden Awards <http://www.ashdenawards.org/int_awards> are looking
>> for projects on renewable energy to be submitted for a possible award.
>> Biogas projects have done well in past years (see the videos listed
>> under Ashden Awards on the Biogas Wikispaces
>> <http://biogas.wikispaces.com/Videos> page). I have added the two that
>> won awards in 2010.
>> If you think you have, or know of, a project that could be classed as an
>> "Energy Champion", that relates to any form of renewable energy do
>> consider applying. The deadline for International Awards is fairly tight
>> - 19 October, so you need to download the information
>> and the forms
>> and fill them in quickly. As well as projects involving biogas, they are
>> also looking for projects on the wider subject of biomass, as well as
>> solar, hydro and wind, or any system that provides or encourages the use
>> of sustainable energy.
>> David Fulford
>> Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
>> d.j.fulford at btinternet.com <mailto:d.j.fulford at btinternet.com>, Tel:
>> +44(0)118 326 9779 Mob: +44(0)7746 806401
>> Kingdom Bioenergy Ltd, www.kingdombio.com <http://www.kingdombio.com>,
>> davidf at kindombio.com <mailto:davidf at kindombio.com>
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <
>> Digestion mailing list
>> to Send a Message to the list, use the email address
>> Digestion at bioenergylists.org
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> for more information about digestion, see
>> Beginner's Guide to Biogas
>> and the Biogas Wiki http://biogas.wikispaces.com/
>> End of Digestion Digest, Vol 2, Issue 31
> Digestion mailing list
> to Send a Message to the list, use the email address
> Digestion at bioenergylists.org
> to UNSUBSCRIBE or Change your List Settings use the web page
> for more information about digestion, see
> Beginner's Guide to Biogas
> and the Biogas Wiki http://biogas.wikispaces.com/
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)
*Please change my email address in your records to: adkarve at gmail.com *
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Digestion