Article 179 of sci.agriculture:
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From: dfathke@uxa.cso.uiuc.edu (fathke donna)
Newsgroups: sci.agriculture
Subject: soil depth
Date: 12 Feb 1994 02:46:57 GMT
Organization: University of Illinois at Urbana
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Summary: what really is productive soil depth?
Keywords: a-horizon,topsoil

 am writing an article re: soil erosion.  In my research, I am running across
 a variety of definitions of productive soil.  There's the A-Horizon, which
 contains organics, good for crops, but some soil people include the  
 B-horizon, or plow level, since adding organics to it turns it into
 productive soil.  I've also heard soil scientists here in the midwest talk
 about soil down to bedrock being made fertile through the use of all the
 fertilizers available to us these days.  That's easy for them to say, since
 the loess around here can be 200 ft. deep, but I don't think it's an
 environmentally sensitive statement to make.

 I'd like to find out, generally, what people in the ag related fields in 
 various parts of the country (or world for that matter) think about this
 topic.  The level of concern about erosion seems to vary with geography
 and geology.  Please provide, along with your comments, what your field
 of specialization is, soil depth conditions in your area, and any other
 info you feel would be useful.

 Thanks,


Article 192 of sci.agriculture:
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From: ropope@iastate.edu (Richard O Pope)
Newsgroups: sci.agriculture
Subject: Re: soil depth
Date: 14 Feb 94 03:26:36 GMT
Organization: Iowa State University, Ames, Iowa
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Keywords: a-horizon,topsoil

In <2jhfv1$4fb@vixen.cso.uiuc.edu> dfathke@uxa.cso.uiuc.edu (fathke donna) writes:

> am writing an article re: soil erosion.  In my research, I am running across
> a variety of definitions of productive soil.  There's the A-Horizon, which
> contains organics, good for crops, but some soil people include the  
> B-horizon, or plow level, since adding organics to it turns it into

Run to the library or bookstore and check out an introdutory textbook on soil
science...  very generally...

   "A" Horizon is the layer, generally nearest the surface (Unless it has
subsequently been buried by newer material) that has been
altered from the original regolith by accumulation of organic matter,
development of soil structural units that are to some degree or another
stable, and may (or may not) demonstrate the direct effects of tillage.  

   "B" Horizons may or may not be present, and generally underlie the A, and
show evidence of soil development.  (clay content increase, leaching of salts,
particularly Ca, Mg, etc., abd attendant changes in color.)  

   For mineral soils; "A" and "B" (if present), {and "E" Horiaons, if any E=
eluviated}, together constitute the solum, or zone of soil formation...
material that is undifferentiated is refereed to as the Parent Material,  ("C"
Horizon, again if present. 

> productive soil.  I've also heard soil scientists here in the midwest talk
> about soil down to bedrock being made fertile through the use of all the

Better check that out, I think you are losing the point by comments or
perceptions that are out of context... Which is not to say we need to work on
better managing farm inputs, but don't brand all as bad until you understand
the context (not meant as a flame at all...)

> fertilizers available to us these days.  That's easy for them to say, since
> the loess around here can be 200 ft. deep,
                               ^^^^^^^^^^^^^ Not in east central Illinois...
Western Iowa, NW Missouri, yes.

 but I don't think it's an
> environmentally sensitive statement to make.

> I'd like to find out, generally, what people in the ag related fields in 
> various parts of the country (or world for that matter) think about this
> topic.  The level of concern about erosion seems to vary with geography
> and geology.  Please provide, along with your comments, what your field
> of specialization is, soil depth conditions in your area, and any other
> info you feel would be useful.

Soil depth varies with the landscape...  here in central Iowa, and there in C.
Illinois as well...   I have an M.S. in Soil Management and work in Integrated
Crop Management and Pesticide Applicator Training in Iowa...  
Again, get a copy of Foth's Soil Science, or any other general intro soils
text, and ask the soils department at U of Ill.  Good luck!

> Thanks,








-- 


Article 200 of sci.agriculture:
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From: eastburn@delphi.com (Robert P. Eastburn)
Newsgroups: sci.agriculture
Subject: Re: soil depth
Date: 14 Feb 1994 23:39:12 GMT
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"... am writing an article re: soil erosion.  In my research, I am running 
across a variety of definitions of productive soil.  

I'd like to find out, generally, what people in the ag related fields in
various parts of the country (or world for that matter) think about this
topic."

Here on the Eastern Shore (east of the Chespeake Bay aka Delaware w/ parts
of Maryland and Virginia), some of us have been using a definition of
biological activity to define the break between soil and non-soil.  This
decision is  based on a definition of soil being the interaction of multiple
soil forming factors per Jenny's analysis.  It is however weighed in favor
of the biota due to the opinion that the biota is what makes soil unique
from inert geologic material.  A good rule of thumb for our area is then 6
ft.  Like all rules of thumb its wrong, but, its close. At least from a
pedologic view.

Edaphologically, we generally figure a 4 ft depth.  Most of our rooting
studies with corn and soybeans indicated the major rooting depth rarely
extending below this depth in our coastal plain soils; in the case of these
studies, mostly Typic Quatrzipsamments.  

BTW, you might try posting your question to the soils-l discussion group at
soils-l@unl.edu.  

Any way that's one opinion.  Like much in soils, it all depends on where you
stand.  One of my co-workers often comments that the last guy leaving the
field is right.  He always leaves after me.   8-)

[Robert P. Eastburn, CPSC  Eastburn JOAT  Clayton, DE, USA]
[Eastburn @ delphi.com.us   CIS 73551,1754    302-653-0769]



Article 205 of sci.agriculture:
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From: jp@unlinfo.unl.edu (jerome pier)
Newsgroups: sci.agriculture
Subject: Re: soil depth
Date: 15 Feb 1994 21:29:16 GMT
Organization: University of Nebraska--Lincoln	
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: BTW, you might try posting your question to the soils-l discussion group at
: soils-l@unl.edu.  

FYI, to join the soils-l mail list send the following message to
listserv@unl.edu:

sub soils-l first last

where first is your firstname and last, well you get the picture!

Jerome Pier
Soils-l List Owner
jp@unl.edu

P.S. Thanks for the advert.



