permaculture

[Lawrence London <lfljvenaura@gmail.com>]

On 5/20/2013 3:36 PM, m_astera wrote:

 ecolandtech <dirt.4arm@...> wrote:
> It sounds like you did a wonderful job of mineralizing your soil, but
> what you added won't necessarily add CEC.
>
> Exchange capacity is the ability of components of the soil to hold onto
> minerals via a static electrical charge. A soil particle with a positive
> + charge can hold a negative ion (an anion) like NO3- nitrate; a
> negative - charge can hold a positive ion (a cation) like K+, Potassium.
> See
> http://soilminerals.com/**Cation_Exchange_Simplified.htm<http://soilminerals.com/Cation_Exchange_Simplified.htm>
>
> Soil components with high CEC, cation exchange capacity, include some
> clays, humus and humate ore, and charcoal. Humus, humates, and charcoal
> also have significant AEC, anion exchange capacity. (AEC is not usually
> measured on soil tests.)
>
> Rock dusts generally have little or no exchange capacity because they
> don't have significant static electrical charge. Florida soft rock
> phosphate is an exception, because it contains a good amount of high-CEC
> clay. Limestone powder, Calcium carbonate, has effectively zero exchange
> capacity; ditto for basalt, granite, etc no matter how small the particles.
>
> Adding fresh rock dusts can easily skew a soil test to read too high in
> exchange capacity because Ca, Mg, K, Na etc will be etched from the rock
> particles, rather than only from exchange sites. One can tell if they
> are likely to have that problem by pouring vinegar on a dry soil sample;
> if it fizzes considerably that means high levels of freely available
> cations, especially Calcium.
>
> The best way to find out the actual CEC of the soil would be to test a
> sample that has not been amended with rock dust.
>
> Michael A
> http://soilminerals.com
>

Thanks very much for your helpful and informative reply, Michael. This
certainly explains much of what CEC and AEC are all about. I will read
your page on this topic and in time will buy a copy of your book.

My thoughts:
I can see that the quarry rock dusts won't improve my soil's CEC but it
will feed the soil microbes, weeds and crops growing in it. The weeds
can be turned under thus returning nutrients to the soil and adding OM
which may increase CEC on its own.

My soil is Georgeville silt loam. It is bright red, high in iron and is
exactly the same consistency and color (except for topsoil on or near
the surface) 3 to 6 feet down where you encounter parent material which
is lighter colored and larger particle size, like a very fine sand,
which blends with eroded fractured pieces of bedrock (where the parent
soil originated) and below that partially eroded bedrock, a kind of
bluestone used to make crushed rock for roads, second hardest rock in
North Carolina.

GnC—Georgeville-Urban land complex, 2 to 10 percent
slopes
http://soildatamart.nrcs.usda.**gov/Manuscripts/NC037/0/**Chatham.pdf<http://soildatamart.nrcs.usda.gov/Manuscripts/NC037/0/Chatham.pdf>

Fundamentals of Soil Cation Exchange Capacity (CEC)
http://www.extension.purdue.**edu/extmedia/ay/ay-238.html<http://www.extension.purdue.edu/extmedia/ay/ay-238.html>
Table 1. Normal Range of CEC Values for Common Color/Texture Soil Groups.
   Soil groups              Examples      CEC in meg/100g
------------------------------**--------------------------
Light colored loams and   Clermont-Miami   10-20
  silt loams               Miami
Dark colored loams and    Sidell           15-25
  silt loams               Gennesee

My goal was to turn red dirt into tan or brown garden soil to as great a
depth as I could afford given the resources I had at the time. I
accomplished this.

Higher CEC is what I need now as my garden beds have gained a fair
amount of compaction with resulting loss of water holding capacity and
plant growth. Over the three years spent on this soil building program I
blended, spread and tilled hundreds of tons of manures and rock dusts
(four kinds, from four different quarries) on 5 acres of land then ended
my project and sold the equipment. I now have a jungle of dense tall
weeds in the fields, more this year than ever before. I can confidently
say that Fukuoka was right.

Here are galleries of pictures of the project:
Preparation:
1)
https://plus.google.com/b/**106181639516457096425/photos/**
106181639516457096425/albums/**5873426643820858097<https://plus.google.com/b/106181639516457096425/photos/106181639516457096425/albums/5873426643820858097>
2)
https://plus.google.com/b/**106181639516457096425/photos/**
106181639516457096425/albums/**5873409948529968017<https://plus.google.com/b/106181639516457096425/photos/106181639516457096425/albums/5873409948529968017>

Preparation & Equipment
3)
http://www.ibiblio.org/london/**venaurafarm/raisedbeds/<http://www.ibiblio.org/london/venaurafarm/raisedbeds/>
For tool, implement and tractor nuts, the most useful pictures of my
tractor and IMO world class implements. See especially:
Equipment, Ponds, Bed Preparation
Roll-A-Cone-Hiller-Bedder
HowardRotavator-50inch
Howard Rotavator
YeomansPlowToolbar
bottomplow-tillagetool-**YeomansPlowToolbar
Yeomans Plow 1
Yeomans Plow 2
Yeomans Plow 3
Yeomans plow 4
Yeomans plow 5
Yeomans plow in use
hiller-bedder-1
hiller-bedder-2
hiller-bedder-3
hiller-bedder-4
hiller-bedder-5
hilling-bedding1
hilling-bedding2
hilling-bedding3
hilling-bedding4

Fields:
4)
https://plus.google.com/b/**106181639516457096425/photos/**
106181639516457096425/albums/**5871242339766436321<https://plus.google.com/b/106181639516457096425/photos/106181639516457096425/albums/5871242339766436321>
5)
https://plus.google.com/b/**106181639516457096425/photos/**
106181639516457096425/albums/**5871242339766436321<https://plus.google.com/b/106181639516457096425/photos/106181639516457096425/albums/5871242339766436321>