[permaculture] Re: soil building reference ?

Lawrence F. London, Jr. lfl at intrex.net
Sat Oct 19 06:27:54 EDT 2002

Joel Gruver wrote:

> Hello Lawrence,
> I am located considerably closer to your neck of the woods than Byron and
> would like to come take a look at your soil building project.
> Perhaps I will even bring some students from the Soil Science class that I
> am teaching at the community college in Pittsboro, NC.

That would be wonderful. You all are welcome any time its convenient to come up 
from CCCC. I'd love for you to see it, analyze, sample, comment on, criticize or 
admire it. You can probably tell I am quite proud and delighted at the way it 
has turned out. The 3 1/2 acres got plowed late in the 2001 winter when the soil 
was wet and we had little rain or freezing weather following that. The disaster 
zone that I faced in Spring is what drove me to the lengths I've described to 
rebuild tilth and at the same time fertility over the acreage.

> I am wondering how you developed the plan for soil building that you are
> currently implementing. Is there a book, an article or some reference that
> articulates the approach to soil building that you are pursuing ?

I moved onto this land 1978 and was a landscape contractor/designer at that time 
and for a number of years afterward. I made all the most obvious mistakes trying
to work up garden soil. Compaction, compaction, hard clodlets, etc. When I 
arrived, in warm weather, after a rain, walking out on the soil in the fields, 
you could see little air bubbles coming out of pores in the soil, making popping 
sounds. I had never seeen this before, must be a characteristic of
Georgeville silt loam that has laid fallow for years. That should have been my
signal to never set foot or tire on this ground except for very controlled 
materials application or tillage. But I was not wise and paid the price with
compaction and loss of native ground cover (lots of red clover, everywhere).
Anyway, as of next Spring it will have been fully restored and then some.

I used no particular references to guide me in my soil improvement program, only 
experimentation and trial and error.
1) found sources for rock phosphate and greensand, horse, cow and chicken manure
and lots of hay (square and round bales) to spread around during summer and fall
2) used the tried and true method used in my region: plow in early winter or 
late fall, utilize freeze/thaw cycles to break down hard clods of soil into 
loose silt by Spring - careful to avoid thermally insulating soil, i.e. no Fall 
application of compost, manure (unless its tilled in) or mulch
I forgot to mention that I regularly had my acreage "plowed" with a Soil Saver
during the warm seasons and/or in the late Fall. This is a very interesting and 
effective tillage tool, heavy duty, goes deep (not as deep as Ford 301 3-bottom 
plow) and takes a big tractor to pull it. There has been some discussion in 
sanet on this implement. The best all around tractor drawn implement is the 
Yeoman's Plow System (a kind of subsoiler/tiller that shatters layers of soil
to a great depth and can put soil in a really fine condition to go into winter 
and, following that, provide tillage to incorporate various materials prior to 
planting or further preparation and fine tuning with other implements.
3) carefully apply rock dusts and rock quarry pond fines, manure and compost
in spring directly along paths that raised beds will follow, then hill, till and 
hill them into shape, followed with hand shaping raised beds of varying widths, 
heights and lengths with hand tools
4) at this point in time I plan to apply apply lots more rock dusts, as many 
tons as I can afford; its the best drought insurance I can think of and the 
added fertility and tilth is almost immeasurable.

There's a lot more I could say good and bad about working this soil but the 
above description contains the most important aspects of the processes I 
followed. I would hope a newbie farmer might avoid all the pitfalls and mistakes 
I had to weather. Maybe this small introduction to farm soil building will be of 

In landscaping I just: 1) removed clay, rock, gravel 2) replaced it with 
enriched topsoil 3) planted shrubs, trees, ground cover 4) mulched planted zones

> You have mentioned that the soils you are amending are of the Georgeville
> soil series... Georgeville soils have inherent properties that are rated
> quite highly for crop production. Why do you feel that the soil on your 
> site requires such intense modification ?

I have really good reasons for doing this. I need fertilizer (manure and rock 
powder) - there has been none on my land for many decades until just recently.
I also need the added tilth, fine soil crumb structure and water retention - 
this means larger and more stable soil microflora populations.
I can show you before and after zones. I now have tilth, fertility and water 
holding capacity that I feel will allow me to prepare highly productive, low 
maintenance raised beds just about anywhere on 3 1/2 acres instead of only
on 1/2 acre, previously. I have to irrigate with well water and need to do that 
as infrequently as possible.

> You have mentioned that rock dusts increase the water holding capacity of
> soil. I am not aware of a phenomena which would cause this to happen... can
> you describe what you have observed that has led you to conclude that rock
> dusts improve water holding capacity.

Absolutely. The volcanic tuff pond fines I used 1) will not become compacted
under any conditions (like clay will) and is permeable 2) added micronutrient 
availability (this dust is "new soil" with its full mineral complement) is 
beneficial to soil microflora which increase friability and fertility of soil 
eventually leading to added organic matter resulting in increased water holding 
capacity 3) the grit of this dust is much finer than that of my Georgeville soil 
so adding large quantities of it to this soil will ensure that the Georgeville 
will a) never become compacted (low organic matter Georgeville compacts easily 
though not as bad as clay) b) Georgeville pore space will be reduced without 
sacrificing friability and permeability resulting in reduced drainage and 
greater water retention (you can plainly see this after rainfall in areas where 
greater amounts of dust have been incorporated). Add manure and/or compost along 
with the rock dust to the soil and you gain maximum water, nutrient and microbe 
retention. Kind of a living system, a nutrient, water and microbe catchment,
a unique ecosystem. There's lots more to this that I want to explore (blew off
by mistake hours of research on the Web, links and downloaded text and graphics
which I hope to regain soon) such as how changes in soil structure and fertility 
like this affect the soilfoodweb and populations of native and introduced 
microflora, the rhizosphere, mychorrizal fungi, nitrogen fixing bacteria, free 
living and symbiotic, protozoa, earthworms, beneficial nematodes and how to 
manage the chemistry of the soil, while adding massive but balanced amounts of 
amendments, to ensure that they survive and flourish.

> It is my understanding that you are planning to leave your intensively
> tilled and highly amended site bare all winter. Is there a reason why you
> don't think it would be beneficial to plant a cover crop ?

A cover crop will insulate the soil from cold temperatures. I want it to freeze 
as hard and as often as possible. This only needs to be done once, usually, for 
any given area that will be turned into permanent notill raised garden beds. 
Next winter I will plant cover crops on those beds; others I may mulch and the 
rest may get plowed once again (within limits the soil improves every year you 
can do this). I do not have hardpan here; the soil is the same consistency all 
the way down to parent material, broken decomposing rock further down and pure 
native rock (maybe more volcanic tuff) below that.

> Looking forward to finding out more about the sources of information that
> are guiding your soil building efforts.

I'll share everything I have on the subject with you as well as all my 
experiences. You definitely need to see this dirt - I have shovels you can use 
to examine the soil profile in various locations. I do have several more acres I 
had plowed, disk harrowed and disk-hilled in an interesting arrangement/grid to 
conserve water as it went through years of laying fallow. This area is now 
covered in volunteer lespedeza, fescue, goldenrod, broomstraw, rabbit tobacco, 
roses, blackberries, pine trees, daisies amd ragweed. Pretty nice maintenance 
stand, conveniently lacking Bermuda, pigweed (I may sow some lambs quarters for 
diversity) or Johnson grass. I have bees at one end of this field.

lfl at intrex.net

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