permaculture

["Lawrence F. London, Jr." <venaurafarm@bellsouth.net>]

-------- Original Message --------
Subject: Re: [SANET-MG] soil fertility
Date: Mon, 28 Mar 2011 13:49:26 -0400
From: Steve Gilman <stevegilman@VERIZON.NET>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Hi Frank,

In my heavily glaciated neck of the woods (northeast US) anyway, there 
seems to be ample soil P -- but it's generally depicted in soil tests as 
chemically bound and unavailable for plant growth. The recommendation 
was to add some form of super-phosphate -- but not allowed under organic 
certification because of the acid formulation for its damage to soil life.

 However, as per my post  -- acids from cover crop roots can liberate 
it, especially buckwheat.
"Managing Cover Crops Profitably" puts it this way:
Phosphorus scavenger. Buckwheat takes up phosphorus and some minor 
nutrients (possibly including calcium) that are otherwise unavailable to 
crops, then releasing these nutrients to later crops as the residue 
breaks down. The roots of the plants produce mild acids that release 
nutrients from the soil. These acids also activate slow-releasing 
organic fertilizers, such as rock phosphate. Buckwheat’s dense, fibrous 
roots cluster in the top 10 inches of soil, providing an extensive root 
surface area for nutrient uptake.

Thrives in poor soils. Buckwheat performs better than cereal grains on 
low-fertility soils and soils with high levels of decaying organic 
matter. That’s why it was often the first crop planted on cleared land 
during the settlement of woodland areas and is still a good first crop 
for rejuvenating over-farmed soils. However, buckwheat does not do well 
in compacted, droughty or excessively wet soils.


To answer your question, my approach was to also apply some rock 
phosphate and then use buckwheat to make the P bioavailable for the 
following crops. Of course buckwheat is also a prodigious smother crop 
for weeds, a great bee and honey crop, and with it's rapid growth habit 
is adept at fitting into small summer windows as a catch crop -- making 
it an excellent overall mineral and soil building tool.

best,
Steve

On Mar 28, 2011, at 1:02 PM, Frank L Teuton III wrote:

> Hi Steve,
>
> So, in a soil where P was not very available, would you suggest growing 
> buckwheat always, and never adding a P rich amendment?
>
> In other words, under what circumstances would you not grow buckwheat but add 
> a P source, if any?
>
> Frank
>
> ----- Original Message ----- From: "Steve Gilman" <stevegilman@VERIZON.NET>
> To: <SANET-MG@LISTS.IFAS.UFL.EDU>
> Sent: Monday, March 28, 2011 12:47 PM
> Subject: Re: [SANET-MG] soil fertility
>
>
> Hi Edna,
>
> Re: buckwheat sequestering P -- the following is from the excellent SAN publication 
> "Managing Cover Crops Profitably"...
>
> best,
> Steve
>
>
> http://www.sare.org/publications/covercrops/buckwheat.shtml
>
>
> On Mar 28, 2011, at 12:00 AM, SANET-MG automatic digest system wrote:
>
> > Date:    Sun, 27 Mar 2011 20:45:59 -0700
> > From:    Edna Weigel <eweigel@CABLEONE.NET>
> > Subject: Re: soil fertility
> >
> > Steve Gilman wrote:
> > <snip>
> > The non-silver bullet alternative (that doesn't require major outlays of
> > currency or legions of consultants to interpret what you need) is to go for
> > a practice-based rather than product-based approach via tried-and-true solar
> > agriculture techniques like cover cropping and green manuring that builds
> > soil flora and fauna, increases stable organic matter, grabs and holds
> > carbon, develops conducive soil structure, scavenges deeper-down soil
> > nutrients, fixes N (legumes) and sequester previously unavailable elements
> > (like buckwheat and P) as well as other fertile soil building practices such
> > as composting and mulching with locally available materials...
> > <snip>
> > Could you elaborate on this or make suggestions for further reading?,
> > particularly "sequester unavailable elements"
> > Edna