Gosh! On one hand I am inclined to wave the organic
farming banner with an "I told ya so"....... because the
notion that chemical fertilizers can harm the soil is something
alternative farmers have been talking about for decades.
In sustainable agriculture, we place a high value on the
observations of farmers. Steeped in land care, it is no small
matter that certain of these farmers did not "feel right" about
the increased use of chemical fertilizers. These observations
about the negative consequences of chemical fertilizers can be
traced back to the mid-1920s when biodynamic farming
evolved in Germany-Austria-Poland as the first ecological farming
system. These farmers noticed deteriorating conditions in their
crops and livestock, and correlated these declines with the
introduction of chemical fertilizers at the turn of the century.
On the other hand, I am impressed with the specific revelations that
came from this University of Wisconsin research. Actually, that is a
nice piece of investigation and clarification by UW soil scientists;
they deserve credit for their insight and skills at discerning this
phenomenom.
Since we don't have the journal article in front of us to evaluate
the data or read their discussion and analysis, it is hard to
understand exactly how the nitric acids produced from
nitrogen fertilizer-induced acidification actually causes
irreversible damage to the cation exchangec capacity of soils.
A couple of points come to mind:
1. Why did the researchers suggest that natural sources of
nitrogen such as legumes (clovers, vetches, cover crops)
cause as much acidification as chemical nitrogen sources
(ammonium nitrate, anhydrous ammonia, etc.)???
If you think about long-term studies and real life situations where
side by side farms are managed by organic or conventional
methods, I am pretty sure you'd find wide enough differences
in soil quality characteristics to disprove the statement that
nitrogen from legumes is just as harmful as chemical nitrogen....
especially when viewed from a whole farm perspective, there are
humus complexes and soil foodwebs that can bind and fix nitrogen
thus preventing its ability to contribute towards soil acidification.
Interestingly, compost is known to raise the pH of acid soils
closer to neutral, as well as lowering the pH of basic soils
closer to neutral. Compost helps soils adjust towards neutral
whether the pH is high or low.
2. The report also noted the importance of calcium, magnesium,
and potassium; cation exhange capacity; and liming.
This brings to mind the notion that eco-farming advisors who've
been emphasizing base saturation and high calcium lime all these
years may have clued into an important principle of good soil
management way ahead of their time. Or, maybe not. Maybe it
is just good plain agronomic husbandry to lime soils whether
base saturation percentages or calcium-magnesium ratios make
a hoot of difference. I mention this particular angle, because base
saturation ratios have been an on-going thread on sanet... and,
because the prominent eco-farming advisors are so emphatic
in their prescription for proper cation balancing.
Anyways, thank you Michele Gale-Sinex for posting this news item
from UW. No matter which way you spin it, it is a significant piece
of research that we need to pay attention to.
For example, a consequence of modern agriculture is that nitrogen
fertilization is contributing very significantly to hypoxia in the
Gulf of Mexico. This nitrogen finds it way into the Gulf via the
Mississippi River because 2/3rds of the nation drains into the mighty
Mississippi. Each year, an area the size of the state of New Jersey
becomes oxygen depleted. This is wreaking havoc on marine
ecosystems, with whole species of creatures dissapearing. The
immediate impact on humans is that fisheries are dying and injurying
the economic livelihoods of whole towns and villages along the Gulf
of Mexico. The meta ecosystem consequences of LARGE sections
of the Gulf experiencing man-induced hypoxia are probably more akin
to the canary in the gold mine..... and when the canary birds
keels over, it is also too late for us, yikes!
Steve Diver
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