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  • From: "Douglas Willhite" <drwillhite@earthlink.net>
  • To: <livingontheland@lists.ibiblio.org>
  • Subject: [Livingontheland] Rethinking soil
  • Date: Mon, 31 Dec 2007 04:38:26 -0800

The Leopold Center folk's are our good allies in raising vital awareness of critical food production issues. Check out their newsletter here:  http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter.pdf.
Doug

Rethinking soil

By Leopold Center Distinguished Fellow Fred Kirschenmann

Winter 2007 Vol. 19 No. 4


 

 


    
The art of land doctoring is being practiced with vigor, but the science of land health is yet
     to be born. – Aldo Leopold

 

 


Soil scientist Hans Jenny reminded us that soil was not a thing, but a web of relationships. Rattan Lal, president of the Soil Science Society of America, recently reaffirmed that insight in an article he wrote for the Crop, Soils, Agronomy News. Reflecting on our tendency to describe crop residues as “waste” (especially in our current rush to use these residues for ethanol production), Lal warned that this was

… a dangerous trend because crop residue is not a waste. It is a precious commodity and essential to preserving soil quality. In addition to controlling erosion and conserving soil water in the root zone, retaining crop residues on the soil is also necessary for recycling nutrients, improving activity and species diversity of soil micro- and macro-fauna, maintaining soil structure and tilth, reducing nonpoint source pollution and decreasing the risks of hypoxia in the coastal regions, increasing use efficiency of fertilizers and other inputs, sustaining biomass/agronomic yield, and improving/maintaining soil organic matter content. (CSA News, Volume 52, No. 5, May 12, 2007)

This comprehensive evaluation of the importance of crop residues to soil health brings to mind the writings of Sir Albert Howard, Lady Eve Balfour and J.I. Rodale who, over half a century ago, lamented our simplistic soil management methods. They argued that simply inserting a few nutrients to achieve maximum production (what Howard called the “NPK mentality”) was, in fact, a kind of “banditry.” Without proper maintenance of health of the entire soil complex, the soil’s “stored fertility” is plundered, and jeopardizes future generations.

We have thus far largely avoided the fulfillment of such predictions because we have used cheap synthetic inputs to mask the effects of the loss of stored fertility in the soil (at least so far as maintaining yields is concerned). As Leopold observed, we have excelled at “land doctoring” but we have invested very little into the “science of land health.”

Since the inputs that facilitate production with little regard to soil health are derived from fossil resources, we may soon find the predictions of Howard and others coming true. The principal fossil resources that have created this productivity – oil, natural gas and groundwater – are now in a state of depletion, so it is imperative that we attend to the science of soil health.

We know from extensive research that when soil is managed to enhance soil quality, practices such as returning crop, livestock and other residues (preferably composted) to the soil, and crop rotations (particularly with green manure crops) will improve soil health. Such practices reduce the need for synthetic inputs and improve water absorption and retention, which decreases the need for irrigation. Now more than ever it is critical to reinvigorate the science of soil health if we wish to maintain productivity in the face of serious resource depletion. We have ignored soil health far too long.

The recent discussion by the Iowa State University Agronomy Department about a possible new Soil Science Institute is not only a great idea but a necessary one. Hopefully the vision of the institute is focused on a science of land health.

 Fred Kirschenmann

More about a Soil Science Institute for Iowa

Grazing by contract, beyond food miles

==========================
THE LEOPOLD LETTER
Quarterly newsletter of the Leopold Center for Sustainable Agriculture
Winter 2007 Vol. 19 No.4
==========================

The current Leopold Letter is now online at http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter.pdf.

In this issue read about a Leopold Center project designed to expand opportunities for livestock producers, especially in southern Iowa, and research that will take Iowans "beyond food miles." Director Jerry DeWitt says sustainability must include animals, and Distinguished Fellow Fred Kirschenmann says healthy soil must include crop residues. You'll also meet Laura Krouse, latest recipient of the Spencer Award for Sustainable Agriculture; and hear from another female farmer and conservationist.

Other articles: A new study estimates the cost of conservation practices on Iowa farms; reports from two well-attended lectures hosted by the Leopold Center; free trips for Iowa farmers to attend a national conference; and a big honor for a Leopold Center staff member.

To read the PDF, you will need Adobe Acrobat Reader. If you do not already have this software, it is available free at http://www.adobe.com/prodindex/acrobat/readstep2.html

In addition, you can go directly to the Leopold Letter Winter 2007 index http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/index.htm
or read each article by following the links below.

-----------------------
LINKS TO EACH ARTICLE
-----------------------

Project fosters custom grazing in Iowa
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/grazing.htm

Traveling 'beyond food miles' crucial to local food efforts
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/miles.htm

Top 10 local food issues (and what the Center is doing about them)
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/local.htm

Q&A WITH THE DIRECTOR: What have been your experiences with animals and livestock in a sustainable agriculture system?
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/director.htm

TOWARD A SUSTAINABLE FUTURE: Rethinking soil
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/future.htm

Spencer Award goes to small-market farmer
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/spencer.htm

Laura Krouse: Planting seeds of sustainability, community
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/krouse.htm

20TH ANNIVERSARY COMMENTARY BY JENNIFER STEFFEN: A farmer's view from the inside
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/anniversary.htm
 
Paying it forward: Free conference trips for farmers
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/trips.htm

Engaging speakers generate lively discussions
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/speakers.htm

Study shows diversity needed for tackling Iowa water quality issues
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/study.htm

Leopold Center accountant named Woman of the Year
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/karen.htm

HIGHLIGHT EVENTS: Spencer presentation, two Leopold Center workshops, John Ikerd
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/meeting.htm

NEWS & NOTES: On-line organic ag course, Center web site sets record, food miles and nutrition, on-line discussion groups, hoop barns and baby pigs
http://www.leopold.iastate.edu/pubs/nwl/2007/2007-4-leoletter/news.htm

To find other items of interest, use the search engine on the Center's web site. The search engine allows targeted searches of the entire site, research results, newsletters and news releases.

Laura Miller, Editor, Leopold Letter
________________________________________
Leopold Center for Sustainable Agriculture ( www.leopold.iastate.edu )
209 Curtiss Hall
Iowa State University
Ames, IA  50011-1050
515.294.5272



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