[Homestead] Soil and fertility

Bunjov at aol.com Bunjov at aol.com
Sun Jan 25 00:38:45 EST 2009


Perhaps a dumb question (although my father told me there was no such  thing) 
-
Could this perhaps be a matter of the fact that the charcoal in the soil is  
the result of native organic matter being burned there, and that's why  
'introduced' charcoal does not have the same effect? Maybe that foreign charcoal  
would have a different effect in its own sphere of influence? 
To everything there is an ecosystem.
Just asking.
Sandy
Mid-Mojave
 
 
In a message dated 1/24/2009 6:17:44 P.M. Pacific Standard Time,  
frank.fries at imagewireless.ca writes:

>  out, it seems, that the charcoal is incidental.  The archeology of the  
> patches
> show that they were intensively gardened continuously  for 3000 years and 
> that's
> why they are permanently  fertile.   >

Having read a fair bit on this, and having  read about the various 
experiments in pots with differing percentages of  charcoal, etc.  it doesn't 
appear that anyone really knows why the  soil is permanently fertile.... 
however, as you said, just adding powdered  charcoal definitely doesn't do 
it.

In the Amazon basin, when they  dig some of the Terra Preta up, as long as 
they only take a little at a  time and leave enough in the patch, it seems to 
"grow back"...  This  implies that it is related to beneficial 
micro-organisms... There is some  speculation that the porous nature of the 
charcoal helps by providing a  beneficial environment for the soil 
micro-organisms.

In one case  that I read about (it was a while ago and I don't have a link to 
it - this  is from memory only) they tried a number of patches in the Amazon 
basin,  in the poor soil  - a control plot (no change to the soil), a plot  
with chicken manure added, a plot with charcoal added and a plot with  
chicken manure and charcoal added.  (I think there were actually a  number of 
plots in each of the categories above, with varying amounts of  manure and 
charcoal added).

As you would expect in infertile soil,  the plot with the chicken manure 
added did better than the control  plot.  It also did better than the control 
plot in the second year  but the improvement was less marked and even less so 
in the third  year.

As I recall the plot with the charcoal added was slightly better,  but not 
much so compared to the control plot.

The plot with the  charcoal and manure was approx. the same as the chicken 
manure plot the  first year, but noticably better the second year and even 
more so in the  third.  There appears to be a cumulative effect.   This may  
possibly be due to micro-organisms getting a chance to breed up and  perhaps 
the charcoal assists in some way.

None of the above is  conclusive and it certainly doesn't necessarily mean 
that the same thing  would work here...it is possible for example that there 
very specific  micro-organisms that exist there and not elsewhere, or ...??

Another  thing I once read was about the beneficial effect of animals on  
soil.   I think everyone (even the agri-biz soil scientist  types) agrees 
that organic matter added to soil is good.  At the very  least, it produces 
nitrogen.  There have been studies proving the  negative effects of cropping 
land and taking all organic residues off (the  straw, stalks, etc).

In the study I read about, they used a number of  fairly large plots that had 
been farm land, and they seeded all but one of  them to some kind of forage. 
The unseeded one was kept fallow.

In  one plot they just let the cover crop (hay/grass) grow and stay on the  
land, eventually decomposing ( I can't recall for sure, but I think they  may 
have cut it and/or chopped it).

In another, they harvested the  hay (and hauled it away).

In yet another, they harvested the hay and  fed it to animals, whose manure 
went back on the soil.  I can't  remember for sure but I think that they let 
the animals harvest it  directly (graze), which of course also looked after 
spreading the  manure.

So on the one plot, nothing was taken away from the soil, on  the second, the 
weight of the hay was taken away, and on the third, the  weight of the 
grazing animals turned into meat was taken away from the  soil.

If it were just volume of organic material, you would expect the  piece with 
nothing taken away to be the most fertile after the  trial.  As I recall, all 
the seeded test plots were more fertile than  the fallowed plot after the 
trial and the most fertile was the one that  had the animals and their 
manure.  It appears that perhaps the  digestion process used by animals adds 
benefits beyond just the organic  material in the manure.

It appears to me that none of this is just cut  and dried, and as the soil, 
moisture and weather changes from one area to  another, different rules 
apply.  It sure is interesting  though.

I look forward to experimenting with different things over the  next few 
years as I get a chance to.... One of the things I mean to try is  raised 
beds.

Frank  

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