Market Farming

[Paul Bucciaglia <pbucciaglia AT yahoo.com>]

Matt,

 

Your best bet is to have your compost tested and then calculate the amount of nitrogen AVAILABLE to your plants.  As was mentioned, N can accumualate to toxic levels in greens if you overferitilize.

 

In my experience, finished compost can range from .7 to 1.5% N.  Usually starting with higher ratios of unbedded manure (like dairy cow or chicken) will increase the %N.

 

Lets take your 40 T/ac rate and guess 1 % N (T=ton, # = pound).

 

40 T/ac X 2000#/T X .01N = 800 #N/ac    Thats 800#'s N/acre!!!!!

 

Now, generally around 1/2 the N is available the first year.  Even so, that means you are applying 400 #'s N to a crop that only needs 50-100#'s N/ac applied (this depends on your current % organic matter in your soil, previous cover crop history, and in my neck of the woods how warm it has been in the few months before planting.  For example, my sandy loam soils are about 3%OM, and I almost always plant into fields that have at least 25#/ac N credit from a previous leguminous cover crop.  That means in mid summer I have at least 100#N/ac before planting.

 

Applying too much N FROM ANY SOURCE will lead to leaching, for sure.  At such high rates soil and plants can't utilize it all. That means pollution, just that same as if you had injected anydrous ammonia into your beds:  nitrate in ground water is happy to come from any source, synthetic or otherwise.  As was mentioned, you run the risk of toxic levels of nitrate in your greens as well.  If you want to improve the physical properties of the soil with large applications of organic material, start with compost that has a higher C:N ratio (use less manure and more 'brown' stuff like straw, woodchips, leaves, etc.).  You will then end up with material with a low %N.  For example, if you use compost with a 0.7%OM at 15T/ac you end up applying 210#N/ac, with 100# N/ac available the first season, a more reasonable amount. 

 

Paul

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Message: 6
Date: Sun, 2 Jan 2005 19:36:51 -0500
From: "cheselka AT theriver.com"
Subject: [Market-farming] Application Rates for Poor Soil
To: market-farming AT lists.ibiblio.org
Message-ID: <178640-2200511303651790 AT M2W099.mail2web.com>
Content-Type: text/plain; charset=iso-8859-1


I'm a bit confused here and I need you experts to straighten me out.

>From everything I've done in terms of research, the recommendation is to
apply 40 tons of compost (or whatever soil improver you choose) to the
acre. Assuming that 1 ton of compost is about 2 cubic yards, then we're
talking 80 yards per acre. With me sofar?

Ok, if you then spread this over the entire acre (43560 square feet), you
get a thickness of the compost layer of a little over 1/2 an inch.

Now, this is where I'm getting confused and/or worried. On my new (virgin
soil) beds that I've been working with for over a year, my modus operandi
has been to put about 2-3 inches of compost (or some other concoction)
down, and then till it all in fairly deeply (8-12 inches). This seems to
be about 4-6 TIMES AS MUCH as what I should be applying.

The reason I'm applying this thickness is that I figure I need to get this
amount mixed into the 8-12 inches of virgin (and fairly poor) dirt below.
I guess I just have a hard time believing that a "mere" 1/2 inch is enough
to give me the kind of improvement to the soil that I'm looking for.

In any case, my veggies last year were VERY VERY happy (for example, my 55
day lettuce matured in 28-35 days and was 18-24 inches in diameter, and
VERY tasty!). But maybe they're a bit *too* happy??

I'm asking this mainly becuase now I'm looking at expanding my production
this year by a very very large amount (about 1000 lbs of veggies a week),
and if I use MY soil improvement rate, I'll need a HUGE volume of compost
(not a problem to get, but it takes *time* to make all that, eh?).

If I AM "over-improving" my virgin soil, then I'd like to know now before I
go and "waste" all that compost and time.

Any suggestions, on-line info, comments, (yes even chastisement,
eye-rolling, or snickering) would be appreciated.

TIA, folks.

Matt Cheselka
Cosmic Lettuce

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Paul Bucciaglia
Fort Hill Farm
Organic Vegetables, Herbs, and Flowers
18 Fort Hill Rd.
New Milford CT 06776
(860) 350-3158
www.forthillfarm.com