food quality collaboration


The Soil Health Department of Rodale Institute is offering an opportunity for food
quality/nutrition collaboration in our two long-term research trials.  We are seeking
researchers who are interested in investigating the effects of conventional and organic
management practices on food quality using these unique experimental sites.

Farming Systems Trial (FST)

        The Farming Systems Trial was initiated in 1981 at the Rodale Institute
Experimental Farm in southeastern Pennsylvania to examine the process of converting from
a conventionally managed cropping system (i.e.  synthetic fertilizers, pesticides,
simple rotation, no cover crops) to an organically managed system.  Prior to the
initiation of this experiment, the site was under uniform management consisting of
nearly continuous maize production for at least twenty years with mineral fertilizer and
pesticides.  The experiment includes three cropping systems and each system is
replicated eight times x three entry points in a split-plot, randomized block design.
Three of the rotational entry points from each cropping system are represented every
year for a total of nine distinct treatments.  One cropping system simulates a beef
operation and applies cattle manure as the major N source and will be referred to as the
manure-based system.  The other two cropping systems simulate cash-grain farming systems
and receive only plant residues.  In the legume-based system, plowdown of redclover or
hairy vetch is the primary N source.  The conventional system receives mineral N
fertilizer prior to maize, and pesticides (mainly herbicides) are applied as needed.
Both the manure-based and legume-based systems are managed organically and do not
receive any syntheric fertilizers or pesticides.  Corn and soybeans are the two crops
that are produced in all cropping systems.  Archived samples, taken every year since the
beginning of the experiment, are available for analysis.

Compost Utilization Trial (CUT)

        The Compost Utilization Trial, established in 1993, was designed as a long-term
experiment to evaluate composts of various feedstocks, maturity, C:N ratios and nutrient
content and compares them to raw dairy manure and mineral fertilizer.  A three year
rotation of corn, green bell peppers and small grain (oats and wheat) was established
with each crop present every year.  Seven treatments are arranged in a split-plot
randomized complete block design.  All amendments were applied on a nitrogen-equivalent
basis, using a 40% availability factor for the composts.  The raw dairy manure and
mineral fertilizer had the highest corn yields in 1993, but in 1994 and 1995, yields in
the compost treatments were comparable to, or higher than those treatments.  There were
no significant yield differences among treatments for green peppers over the course of
the three years.  Differences in NPK accumulations over time have been studied with an
emphasis on the nutrient imbalances caused when using compost as the sole source of
nitrogen in a cropping system.  In this experiment, wheat, corn, and peppers are
produced in all treatments and archived samples are available for analysis.
        A preliminary study was conducted on the vegetable crop of 1993, in cooperation
with the USDA Agricultural Research Service, Beltsville, MD to look at management
effects on mineral and vitamin contents.  Iron bioavailability and the content of
ascorbic acid, iron, copper, zinc and manganese were determiend in spinach and green
peppers grown with three organic fertilizers and one conventional fertilizer.  The
percent of the soluble iron that was bioavailable was significantly higher for organic
treatments than for the conventional fertilizer treatment in both spinach (p<.06) and
green peppers (p<.001).  Content of ascorbate was greatest in green peppers from organic
compost treatments.  Mineral content was generally higher in conventionally fertilized
spinach and peppers.  This trend was significant for zinc levels in spinach (p<.1) and
for zinc and manganese in green peppers (p<.01).  Possible mechanisms contributing to
these differences have been studied.

Anyone interested in discussing collaborative work along these lines should contact:
Wendy Herdman, Rodale Institute