[permaculture] yield of conventional vs organic farms

Lawrence F. London, Jr. lflj at bellsouth.net
Sun May 13 22:11:43 EDT 2012


-------- Original Message --------
Subject: Re: [SANET-MG] yield of conventional vs organic farms
Date: Sat, 12 May 2012 13:02:38 -0400
From: Michael Astera <michael.astera at GMAIL.COM>
To: SANET-MG at LISTS.IFAS.UFL.EDU

Yield, as used in the title of this thread, infers that quantity, bushels
and tons, is a valid primary criteria for measurement of agricultural
success and that comparing quantity of production between systems of
agriculture gives us a useful basis by which to evaluate them. I disagree.
Quantity of production is a valid measure of mine output if one is mining a
homogenous geological formation, but I would argue it is a deceptive and
false criteria for most other things, particularly agriculture.  Even when
speaking of fiber production, as in bales of cotton per acre, the quality
of the fiber grown is at least as important as quantity, and the disparity
between quantity and quality becomes even more important when food is being
grown.

A quick web search for "high magnesium vegetables" brings up kale, beans,
and pumpkin seeds.  That tells us, at best, that those crops have the
ability to accumulate magnesium, but it is no guarantee that the beans we
are growing or buying are high in magnesium or even contain enough
magnesium to be worth eating if one is Mg deficient.  The same goes for all
of the essential minerals, vitamins, proteins, carbs, and fats: a given
crop may in some cases be high in one or all nutrients, but there is no
guarantee that the vegetable you are eating has much if any of what your
body may need, or what you have been told that food is high in.

The mineral nutrients available in the soil reserves are the absolute limit
on what the crop can contain; that limit is further complicated by the
balance of minerals in the soil, as an excess  of one mineral such as
potassium may interfere with uptake of magnesium even if Mg reserves are
adequate.  Similarly, phosphorus uptake will by limited by a deficiency of
zinc in the soil.  Further, the crops require a number of elements as
catalysts in order to form complex carbohydrates, lipids, vitamins, and
proteins; if those are not in the soil or not in a form available to the
crop, they will not be made and the food grown will not contain them, even
if the same crop grown on the next field over contains them in abundance.

All this is further complicated and potentially compromised by many decades
of plant breeding which has selected for appearance, uniformity, large
yield, and shipping and storage qualities with no thought given to
nutritional quality; the result is that many commercial crops may not have
the ability to take up and utilize much of the essential minerals even if
they are available in the soil, nor the ability to use those mineral
elements to catalyze significant quantities of complex biological
structures like vitamins.

I would suggest that a better criteria for comparing one system of
agriculture to another would be the nutritional quality of the crops
grown.  If two farmers are growing corn (maize), and both are producing 100
bushels per acre, but one farmer's corn is 5% protein and provides 10% of
the RDA of magnesium per serving, while another farmer's corn contains 12%
protein and 50% of the RDA of Mg, comparing yields alone is not useful.

Michael Astera
http://soilminerals.com



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