Subject: UW release: acid linked to soil aging

From: "Michele Gale-Sinex/CIAS, UW-Madison" <[email-masked]>
Date: Wed, 10 Mar 1999 17:16:50 -0500

Howdy, all--

Thought this CALS press release might interest some of you. I'm not 
sure what that second-to-last sentence means/implies, but 
otherwise...enjoy.

peace
misha

Science Report

Agricultural and Consumer Press Service	
College of Agricultural and Life Sciences 
440 Henry Mall
Research Division/University of Wisconsin-Madison
Madison  WI 53706	(608) 262-1461		

     For Immediate Release
     For More Information:
     Phil Barak (608) 263-5450
     [email-masked]

ACID LINKED TO SOIL AGING
Thirty-seven years of data collected from a plot at the University of
Wisconsin-Madison's Arlington agricultural research station is
yielding alarming results: acidification from excess fertilizer is
wearing out the soil. 

Phillip Barak, UW-Madison associate professor of soil chemistry and
plant nutrition, said he is part of a team carrying on research that
started in 1962. Barak and his colleagues have found the cation
exchange capacity, or the soil's ability to hold onto small bits of
calcium, magnesium and potassium, decreases because of soil acidity.
"This change is irreversible," he said. 

According to Fred Madison, UW soil science professor, this is
important news for farmers. "Now you've got a whole path of
destruction," he said. Producers may have overlooked the danger that
excess nitrogen poses to groundwater, but evidence that it may also
permanently damage the soil is beginning to garner attention,
Madison said. 

Barak said health experts have long known the role that nitrogen
plays in blue baby syndrome, a condition in which high levels of
nitrogen inhibit the blood's ability to transport oxygen. Barak said
soil becomes more acidic when nitrogen sources, whether from urea,
legume plowdown - such as alfalfa and red clover - or commercial
fertilizer are not completely used up by the crop. 

This excess nitrogen becomes nitric acid, which destroys the soil's
vital ability to retain the calcium, magnesium and potassium
necessary for crop growth. Instead, these nutrients leach out of the
soil and into the groundwater.  Although they are harmless, they do
cost money to replace - a price that Barak estimates at 20 percent of
what farmers normally spend on nitrogen fertilizers.

According to Barak, the United States has a 50 percent applied
nitrogen efficiency rate. This means only half of the nitrogen
applied by farmers is actually taken up by the plants, leaving the
other half to become nitric acid, he said. "That's like a tanker
truck of nitric acid being dumped on a field," Barak said. 

These tons of unneutralized nitric acid age the soil very quickly,
according to Barak.  He said the soil at his Arlington test site has,
in 30 years of "normal" agricultural acid inputs, aged the equivalent
of 5,000 years with natural source acid inputs.

Barak said the aging is remarkable considering the age of the soils. 
"Keep in mind these soils have only been in existence for 10,000
years," he said. 

Barak said the fine soils of Wisconsin are "tender," and the very
qualities that make them fertile also make them vulnerable.  They are
easily dissolved by acidity, he said. According to Barak, if excess
nitrogen inputs continue, unneutralized, northern soils might soon
become like the sandy, less productive soils of the southeast region
of the United States. 

"With the long term, over-application of nitrogen, we run the risk of
irreparably damaging the soil," Madison said. 

But Barak said the news is not all bad.  He cited two ways farmers
can better care for their valuable soil. The first, and preventative,
measure is to use nitrogen more efficiently. Producers should account
for all sources of nitrogen, and adjust their commercial inputs
accordingly. Excess nitrogen not only acidifies, it can leach into
groundwater or run off into surface water. 

The second, and remedial, measure is applying agricultural lime. 
Liming can neutralize the damaging acid and protect the fields. 
"Agliming has been known for 3,000 years," Barak said. "Use it.  It's
like TUMS for the soil."  By closely monitoring pH levels and
appropriately applying agricultural lime, farmers can greatly retard
what Barak refers to as "accelerated soil weathering." 

Since 1950, Barak reports that nitrogen use, as well as agricultural
production, has skyrocketed. The United States is locked into a
system of high production that cannot be reversed without serious
negative implications, he said.  The result is that farmers must
learn to be more attentive to their treatment of the soil.

###
Writer:  Andy Napgezek, 836-6651
[email-masked]

This story first appeared in the March 3, 1999 issue of the Badger
Herald, an independent student newspaper at the University of
Wisconsin-Madison.

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Michele Gale-Sinex, communications manager
Center for Integrated Ag Systems 
UW-Madison College of Ag and Life Sciences
Voice: (608) 262-8018   FAX: (608) 265-3020
http://www.wisc.edu/cias/
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would look for yours on earth.  --Bob Marley

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From: Steve Diver <[email-masked]>
Date: Wed, 10 Mar 1999 19:56:55 +0000

Michele Gale-Sinex wrote: 
> Thirty-seven years of data collected from a plot at the University
> of Wisconsin-Madison's Arlington agricultural research station is

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