Healthy soil and sustainable growing

["TradingPostPaul" <tradingpost@riseup.net>]

Do-it-yourself soil fungi from Rodale research - or else pay good money for
what's naturally occuring in your own soil.  Low tech, not rocket science.

paul tradingpost@lobo.net
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RESEARCH UPDATE: New Farm Research
http://www.newfarm.org/depts/NFfield_trials/0404/mf_update.shtml

Cultivating beneficial soil fungi to increase yields
Low-cost, on-farm system for producing mycorrhizal fungi
inoculant takes another step forward

        April 6, 2004: Results are in from the 2003 field tests of a low-tech
system for cultivating mycorrhizal fungi (MF) to improve plant health and
boost yields.

In preliminary trials at The Rodale Institute Experimental Farm,
substantial differences were found in the response of MF populations to
different soil environments. Test plots designed to demonstrate how farmers
can produce their own MF inoculant—to use in a greenhouse mix, for
instance—showed that two key MF species performed better when grown with
a dairy manure-leaf compost or a yard clippings compost than when grown
with a controlled microbial compost.

The different MF response may be attributable to the higher phosphorous
levels in the controlled microbial compost, since MF populations are
believed to be inhibited by high phosphorous conditions. The 2003 data will
help researchers refine the MF inoculant production system so that it can
be passed on to farmers.

The inoculant production research is part of a multi-year project led by
Agricultural Research Service scientist Dr. David Douds. A soil
microbiologist who has dedicated his career to the study of mycorrhizal
fungi, Douds has been collaborating with Rodale Institute researchers since
1989, studying the effects of conventional and organic farming practices on
MF populations and the effects of MF populations on crop yields.

Previous years' field studies found higher and more diverse MF levels in
organically-farmed than in conventionally-farmed soils, in part because of
the use of over-wintering cover crops in organic systems. Field experiments
have also demonstrated dramatic yield increases when crops were inoculated
with MF: up to a 34 percent yield gain in sweet peppers, and up to a 45
percent gain in potatoes.

The on-farm inoculant production system should enable farmers to realize
similar yield increases with minimal costs. "These systems could become as
common as a compost pile" for organic and sustainable farms, notes Rodale
research technician Matt Ryan. Constructed out of landscape fabric, the
yard-square planting enclosures are simple to build and require little
maintenance other than watering.

This season, Douds and the Rodale researchers will repeat the experiment
with a few adjustments based on the 2003 results. The yard clippings
compost and the dairy manure-leaf compost—which produced the best results
at higher concentrations—will be tested at compost:vermiculite mixtures
of 1:1, 1:2, 1:4, and 1:9. The controlled microbial compost—which
produced the best results at lower concentrations—will be tested at
dilutions of 1:9, 1:19, 1:49, and 1:99.

In addition, Douds plans to evaluate the feasibility of using native soils,
instead of host plants pre-inoculated with MF, in the production system.
Reasoning that undisturbed soils from a given farm—say from a hedgerow or
native prairie remnant—should contain the MF species best suited to the
local conditions of that farm, the researchers will mix controlled amounts
of native field soils into sterilized compost:vermiculite mixtures, and
then plant non-inoculated host plants into the enclosures.

A final, more elementary possible refinement is the use of large
bags—either of woven polyethylene or of burlap—for the propagation
system, rather than having farmers construct the raised beds out of sheets
of landscape fabric and wooden stakes. In addition to being simpler, using
bags would enable farmers and growers to start the MF propagation beds in
the greenhouse in early spring, and then move them outside when conditions
permit. Last year's results indicate that inoculant enclosures started
earlier in the season produced significantly more viable MF propagules.