Group Title: Agricultural research (Washington, D.C.)
Title: Agricultural research
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Title: Agricultural research
Uniform Title: Agricultural research (Washington, D.C.)
Physical Description: v. : ill. ; 25-28 cm.
Language: English
Creator: United States -- Science and Education Administration
United States -- Agricultural Research Administration
United States -- Agricultural Research Service
Publisher: Science and Education Administration, U.S. Dept. of Agriculture :
Science and Education Administration, U.S. Dept. of Agriculture :
Supt. of Docs., U.S. G.P.O., distributor
Place of Publication: Washington D.C
Publication Date: April 1998
Frequency: monthly[1989-]
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monthly[ former july 1953-198]
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regular
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Subject: Agriculture -- Periodicals   ( lcsh )
Agriculture -- Research -- Periodicals   ( lcsh )
Agriculture -- Periodicals -- United States   ( lcsh )
Agriculture -- Research -- Periodicals -- United States   ( lcsh )
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 Notes
Statement of Responsibility: U.S. Department of Agriculture.
Dates or Sequential Designation: Began with vol. 1, no. 1 (Jan. 1953).
Issuing Body: Vols. for Jan./Feb.-Nov. 1953 issued by: Agricultural Research Administration; Dec. 1953-<Sept. 1976> by: Agricultural Research Service; <June 1979>-June 1981 by: the Science and Education Administration; July 1981- by: the Agricultural Research Service.
General Note: Description based on: Vol. 27, no. 7 (Jan. 1979).
General Note: Latest issue consulted: Vol. 46, no. 8 (Aug. 1998).
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Bibliographic ID: UF00074949
Volume ID: VID00016
Source Institution: University of Florida
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Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - ABP6986
oclc - 01478561
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issn - 0002-161X

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FORUM


Teaming Up
To Examine
Planet Earth
The reason we had so much
advance notice of the latest El
Niiio-the periodic weakening of
trade winds in the Pacific that causes
a shift in ocean currents-is that
several environment-monitoring
satellites detected it at its inception
last March.
In the next 2 years, the National
Aeronautics and Space Administra-
tion (NASA) will launch more than
10 such satellites. This will form
what NASA describes as "the most
aggressive constellation of satellites
in the history of this planet." They
are designed to give the Earth a
complete physical examination as
part of NASA's "Mission to Planet
Earth."
The exam may take 25 or more
years. The resulting understanding of
Earth as a system should help point
to ways to protect the planet's health.
One goal is to predict critical
weather and climate conditions-not
5 days ahead, as is possible with
current satellites, but perhaps a
month or a growing season ahead.
This issue's cover story tells how
USDA's Agricultural Research
Service soil moisture experts joined
with many other scientists supported
by NASA to turn the Planet Earth
"stethoscope" on a large swath of
Oklahoma to gain new insights into
land-atmosphere interactions that
may have parallels with the El Nifio
phenomenon. Depending on geogra-
phy and season, anomalous or
unseasonable conditions in soil
moisture over a large enough area
can affect regional-and possibly
global-climates.
The SGP97 (Southern Great Plains
97) project, supported jointly by


NASA and several other federal
agencies, is led by Tom Jackson of
the ARS Hydrology Laboratory in
Beltsville, Maryland. It is the latest in
a series of cooperative projects with
Beltsville scientists dating back to
1978. This cooperative relationship
has been aided by proximity: NASA's
Goddard Space Flight Center is next
door to ARS' Beltsville Agricultural
Research Center. And Goddard has
the biggest share of NASA's Mission
to Planet Earth assignment.
NASA headquarters' land surface
hydrology program manager, Ming-
Ying Wei, is as pleased as Jackson is
by the data taken in SGP97, saying it
gives scientists the type of knowledge
needed to design a global observing
system for soil moisture.
The Beltsville scientists also work
with scientists at NASA's Marshall
Space Flight Center in Huntsville,
Alabama, and NASA's Jet Propulsion
Laboratory in Pasadena, California.
ARS scientists from other labs,
including those in Ames, Iowa,
Riverside, California, and Phoenix
and Tucson, Arizona, also work
closely with NASA.
This ARS-NASA cooperation has
dividends for other USDA agencies
as well. In 1985, the National Agri-
cultural Statistics Service (NASS),
Foreign Agricultural Service, Farm
Service Agency, and Natural Re-
sources Conservation Service signed
an agreement under which ARS
provides research assistance to
improve crop and land assessment
reports.
One very visible result of this
cooperation is the biweekly "green-
ness" maps that NASS began putting
on the World Wide Web last year.
(Go to http://www.nass.usda.gov/
research) These maps of the continen-
tal United States use a sensor on a
National Oceanic and Atmospheric
Administration satellite to estimate
the development and vigor of crops


by the amount of chlorophyll in the
leaves.
In 1998, NASA plans to launch the
MODIS satellite, which will have a
new and improved sensor to collect
data for these maps. It will have
better spatial resolution and be better
equipped to handle atmospheric
interference.
George Hanuschak, associate
director of the research division of
NASS, says that by giving a big
picture on crop development and
vigor, the maps can sometimes
provide policymakers informative
views of an unfolding disaster. One
example was the cold and windy
winter of 1995-1996 that, when
combined with a subsequent spring
drought, did heavy damage to major
winter wheat-growing areas of the
United States.
Paul Doraiswamy, who is with
ARS' Remote Sensing and Modeling
Laboratory in Beltsville, has helped
NASS develop the mathematics
model needed to generate the green-
ness maps from the satellite sensor.
Doraiswamy is a member of the
vegetative assessment and mapping
team for the SGP97 study.
In another project, Doraiswamy is
developing methods for integrating
data from satellites with crop simula-
tion models to supplement NASS
crop estimates data. This would be
yet another example of the payoffs
from USDA-NASA cooperation, with
international implications for every-
one-from farmers to stockbrokers
and crop insurance agents to urban
residents.

David A. Farrell
ARS National Program Leader
Hydrology/Remote Sensing


Agricultural Research/April 1998








April 1998
Vol. 46, No. 4
ISSN 0002-161X


Agricultural Research is published monthly by
the Agricultural Research Service, U.S.
Department of Agriculture, Washington, DC
20250-0301.
The Secretary of Agriculture has determined
that this periodical is necessary in the transac-
tion of public business required by law.
Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Ruth L. Coy, Acting Director
Information Staff
Editor: Lloyd McLaughlin (301) 344-2514
Assoc. Editor: Linda McElreath (301) 344-2536
Art Director: William Johnson (301) 344-2561
Acting Photo Ed: Scott Bauer (301) 344-2957
Assoc. Photo Ed: Anita Daniels (301) 344-2956
Information in this magazine is public property
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mail lmclaugh@asrr.arsusda.gov
This magazine may report research involving
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cussed herein have been registered. All uses of
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Agricultural Research



World Weather: The Soil Has a Role Too 4

Fractals-A Bridge to the Future for Soil Science 1

What To Expect From Mothers in the Military 14

Deep-Rooted Safflower Cuts Fertilizer Losses 17

Harvesting Drugs From Medicinal Plants 18

Better Cold-Weather Starts for Biodiesel Fuel 21

Hard-To-Control Weeds Need a Mix of Measures 22

Measuring Odors From Livestock Operations 24

Transgenic Alfalfa Yields New Products 25

Science Update 26

Beltsville Symposium XXIII: Food Quality and Safety 28





Cover: At the Grazinglands Research Laboratory operated by the Agricultural
Research Service in El Reno, Oklahoma, hydrologist Bill Kustas installs a remote
sensor to measure soil surface temperature. Helping with the installation are John
Norman of the University of Wisconsin (left) and graduate student Tracy Twine.
The intersecting arches provide stability and hold instrument cables out of the way.
Photo by Jack Dykinga.



In the next issue!

0 With nearly 8 billion chickens processed each year, poultry
inspectors are looking to machine vision and other automated sensing
equipment to help them check for wholesomeness.

(0 Understanding how the nutrients in the milks of various mammal
species contribute to development will help researchers find better
formulas to nourish infants who can't be breast-fed.

E New soybean varieties for grazing, silage, or hay offer double-
cropping possibilities as well.


Agricultural Research/April 1998




































planes flew over Okla-
homa into the border
between wet and dry
weather fronts. This atmospheric
border zone spawns air turbulence
that can affect local and, possibly,
global weather. The boundary grows
to more than a mile above ground
during the heat of the day. At night,
as land temperatures drop, it shrinks.
One of the two planes was a Twin
Otter flown for the National Research
Council of Canada; the other, a Long
EZ experimental plane flown by the
National Oceanic and Atmospheric
Administration (NOAA). Both planes
were part of an international fleet
comprising 6 planes and 15 satellites,
including the Russian Mir space
station.
The fleet's mission: a joint USDA-
NASA hydrology project called the
Southern Great Plains 97 project
(SGP97). Its purpose: to map soil
moisture daily by airplane, using
sensors that are prototypes for future
satellites, with intermittent back-up
from satellites. Together, the fleet
mapped a 24-mile-wide rectangular
path stretching 150 miles and bisect-
ing the middle of Oklahoma, almost


from its border with Texas right up to
its border with Kansas.
"During droughts, the air gets very
warm and dry over winter wheat


JACK DYKINGA (K8016-7)


A tethered weather balloon carrying
instruments to measure humidity,
temperature, and windspeed is launched by
Les Showell (right) of the National Weather
Service' National Severe Storm Laboratory,
Christa Peters-Lidard of the Georgia
Institute of Technology, and graduate
student Luke Davis at the U.S. Department
of Energy's Atmospheric Radiation
Measurement site in Lamont, Oklahoma.


fields that have been harvested and
left bare," says ARS hydrologist
Tom Jackson. "But air becomes cool
and wet when it passes over irrigated
fields, or over pasture or prairie
grasses after a rain.
"This work," he adds, "should
help us find out how large an area
has to be in order to affect weather,
producing a thunderstorm, for
example. Knowing this, in turn,
would help us make global climate
change models more accurate, while
at the same time helping farmers
plan their irrigations."
Jackson is based at the Hydrology
Laboratory run by USDA's Agricul-
tural Research Service in Beltsville,
Maryland. He was chief researcher
for the entire SGP97 project.
The project, proposed by Jackson,
was greatly expanded when NASA
made it part of its climate-
monitoring Mission to Planet Earth
project.

(Continued on page 6)


Agricultural Research/April 1998







































A Good Place To Start
the SGP97
Surrounding the old buildings and
stables at historic Fort Reno in El
Reno, Oklahoma, which was estab-
lished in 1875, is gently rolling prai-
rie land-an ideal site for the South-
ern Great Plains 97 project (SGP97).
At Fort Reno, home of ARS'
Grazinglands Research Laboratory,
plants, soil, and climate are just what
the SGP97 researchers needed.
Wheat, bermudagrass, old world
bluestem grass, winter grass, and na-
tive prairie-3,000 acres of which
have never been plowed-grow on
the laboratory's 6,400 acres.
Soil characteristics are similar to
those of neighboring farms in the
Southern Great Plains.
"Soil water in this region is simul-
taneously a critical and limiting re-
source due to low rainfall conditions
and high evaporation," says El Reno
soil scientist Patrick J. Starks. "So
we need to be able to better predict


and monitor soil moisture. It is im-
portant for farmers to know how
much water the soil contains during a
particular growing season. By know-
ing how we're using the soil's water,
n e can decide what to plant, ho%\ to
plant it, and when to plant it."
For example, he says farmers may
want to plant a second crop after they
harvest their wheat. They can make
more fruitful decisions if they know
how much moisture is in the soil and
how much \% after a particular crop
needs. Until now, a farmer just took a
chance that conditions were adequate
to grow a second crop.
Data from the SGP97 experiment
will help answer these questions. The
El Reno scientists monitor Fort Reno
and the lab's nearby 236-square-mile
Little Washita River experimental
watershed year-round.
"We use t o types of instrument
packages, Micronet and SHAWMS
stations, to monitor soil and related
environmental conditions," Starks
says.


Micronel is a s\ stem of 42 meteor-
ological stations scattered across the
Little Washita. They measure soil
temperature, relative humidity and air
temperature, incoming solar radia-
tion, and rainfall. ARS scientists use
similar instruments to monitor the
soil and climate at Fort Reno.
Both sites have a SHAWMS-Soil
Heat and Water Measurement Sys-
tem. It collects data on soil water con-
tent, temperature, and soil heat flux.
Starks hopes that the SGP97 ex-
periment will bring him and his col-
leagues closer to understanding what
is happening to soil-water content
and runoff so that in the future they
can make more accurate predictions.
"Ground equipment and remote
sensing equipment, such as satellites,
used in the SGP97 project, will bring
us closer to understanding and pre-
dicting the things we need to know to
manage our resources better," Starks
says.-By Tara Weaver, ARS.
Patrick J. Starks is in the USDA-
ARS Grazinglands Research Labora-
tory, 7207 West CheI' yenne St., El
Reno, OK 73036; phone (405) 262-
5291, fax (405) 262-2733, e-mail
pstarks@grll.ars.usda.gov *













"Ultimately, we want to be able to
predict soil moisture anywhere in the
world on any day of the year," says
Jackson.
From June 18 to July 17 last
summer, planes and satellites moni-
tored how torrential rain and its rapid
evaporation in 100F heat affected air
turbulence and weather, including
tornadoes.
A Lockheed P-3B Orion flew in
from NASA's Wallops Flight Facility
in southern Maryland. With a soil
microwave sensor in its bomb bay,
the P-3B mapped soil moisture and
temperature from 22,000 feet. It flew
almost daily, passing over the entire
study area between 9:30 and 11:30 in
the morning.
Jackson says the P-3B also sent
out laser beams to map a vertical
profile of water vapor from plane to
ground.
Other aircraft monitoring the area
were the National Science Founda-
tion's Cessna Citation based in North
Dakota, a Piper Navaho Chieftain
flown by the Ontario (Canada)
Provincial Remote Sensing Office,
and a U.S. Department of Energy
(DOE) Cessna Citation.
DOE's Cessna, flown at 16,000
feet, carried a prototype of a thermal-


At the aircraft mission control center in Oklah<
City, NASA's Ann Hsu checks statewide weather
conditions for Oklahoma.


infrared instrument
that maps soil
surface temperature.
A Mission to Planet
Earth satellite
carrying this instru-
ment will soon be
launched.
The satellites
included U.S.
defense and NOAA
weather satellites
and radar and other
satellites from Japan,
Europe, and Canada.
On the ground,
about 100 scientists
and assistants from
various countries
scurried to coordi-
nate ground mea-


Microwave radiometers mounted on this boom truck can
quickly measure soil moisture.


surements with the
airplanes and
satellites. Hazards
abounded: bulls, brambles, heat,
humidity, high winds, and critters
that chewed electrical wires.
Jackson says the atmospheric
boundary layer study made SGP97
unique compared to earlier studies-
at Arizona's Walnut Gulch in 1990
and in southwestern Oklahoma's
Little Washita River watershed in
1992.
"We're starting to
better understand the
interactions between
this layer and the soil
surface," Jackson says.
"It looks like the scope
and distance of their
effect on climate could
be broader and farther
than we thought. They
involve similar shifts in
moisture and tempera-
ture seen in the ocean-
atmosphere interaction
oma with El Nifio."
!r Everything on the
ground was measured


three ways: by airplane, satellite, and
ground testing. Air-its turbulence,
chemistry, temperature, and
moisture-was measured from
airplanes and on the ground.
Ground measurements are ex-
tremely accurate, but only for a small
point on the land, Jackson says.
"Airplanes cover large areas and
help us bridge the gap by verifying
extrapolations we make from ground
points to the large areas typically
observed by satellites."
The hydrology project built upon
the earlier projects. It included the
Little Washita again as one of three
on-ground sampling sites, along with
the ARS Grazinglands Research
Laboratory at El Reno, Oklahoma,
just above the Little Washita, and the
DOE's Central Facility near the
Kansas border. The three sites were
used to verify the aerial information
and were within the 3,600-square-
mile aerial mapping path.
The Central Facility site sits in the
middle of a 55,000-square-mile DOE


Agricultural Research/April 1998









JACK DYKINGA (K8018-7)


meteorological study area that
stretches from Oklahoma into central
Kansas. The entire DOE area has
been described as a weather station
without walls. Its "floor" is more
than 350,000 acres of grass- and
wheatlands. DOE technicians launch
at least nine weather balloons every
day, on the hour, year-round. Only
part of this area was mapped for this
project.
Jackson says these sites were
chosen for SGP97 because they have
the most extensive networks of soil
moisture sensors and meteorological
instruments anywhere in the world.
Much of the land at the three sites
is rangeland, a land-use type that
covers at least 40 percent of the
Earth's surface. This is why under-
standing what happens when wide-
spread storms strike rangeland is
important to making global predic-
tions of everything-from weather
to soil moisture to erosion to pesti-
cide movement to flooding-
Jackson says.
Jackson and his crew found what
they were looking for on June 17,
the day they arrived: a torrential
downpour over most of the study
area. They watched the P-3B fly
every day, mapping the drying out of
this zone. This pattern-alternating
rain and drought-repeated itself
several times throughout the study.
The study ended with a dry-out
period following a 6-inch downpour
in the southern part of the flight
path.
"The alternation between rain and
drought is exactly what we needed,"
Jackson says.

Adios MIR, Adios ADEOS
While the weather, airplanes, and
ground crews played their parts with
near perfection, the researchers'
orbiting "eyes" ran into problems.
As the project began, the P-3B


airplane and the Mir station passed
over, capturing soil moisture data
across both the mapping area and a
wide swath of the United States. But
a week later, on June 25, the re-
searchers and an anxious world
learned that a docking accident had
severely damaged MIR, temporarily
knocking out all power. While power
for life support was quickly restored,
it would be several months before
power for experimental apparatus
such as the soil microwave sensor
would be available.
Compounding the problems for
researchers, another satellite involved
in the project-Japan's ADEOS
satellite-spun out of control 10 days
later and was lost in space forever.
Still, the P-3B plane, carrying two
types of soil moisture microwave
sensors, flew the flight path 22 out of
30 days. This was exactly what
Jackson and his colleagues had


JACK DYKINGA (K8018-1)


At ARS' Little Washita watershed near Chickasha, Oklahoma, Teferi Tsegaye of Alabama
A& M University (foreground) demonstrates a soil measurement technique as other
students and Bill Crosson of the Global Hydrology and Climate Center look on.


Agricultural Research/April 1998


Alabama A&M University students
Jimmy Moore (foreground) and Jacques
Surrency weigh soil samples in prepara-
tion for moisture measurements.











JACK DYKINGA (K8017-91


planned for, knowing from experi-
ence that it is about as close to
perfection as Nature and airplane
logistics allow.

Meanwhile, Down Below
Students and faculty from Ala-
bama A&M University's NASA-
sponsored remote-sensing center
helped gather data. The University
benefits from being in Normal,
Alabama, near NASA's Marshall
Space Flight Center in Huntsville.
A&M University students joined
graduate students from around the
country in making ground measure-
ments on government rangeland.
Other ARS participants included the
Grazinglands Research lab at El
Reno, the Soil Tilth Laboratory at
Ames, Iowa, and the Salinity Labora-
tory at Riverside, California.
At the El Reno site, Jackson's
Beltsville colleague, hydrologist Bill
Kustas, supervised measurement of
meteorological conditions at four
locations. At each site, 10-foot
towers supported sophisticated
instrumentation for measuring air
turbulence at ground level. One
tower was toppled by extreme wind
gusts and had to be repaired.
Kustas kept an eye on weather
reports. He often brought his crew
out at 5 a.m. to beat a storm, down-
load the previous day's data, and put
protective bags over sensitive
instruments to protect them from hail
and blowing debris.
The P-3B aircraft unfurled from
its bomb bay an experimental soil-
moisture sensor-a bundle of anten-
nae "sticks" called ESTAR, for
Electronically Scanned Thinned
Array Microwave Radiometer.
"The antennae receive natural
microwave emissions from the soil.
The weaker the emission, the more
the soil moisture," Jackson explains.
Together, the sticks, each about 3


At the Oklahoma City Airport, Canadian pilot Dave Bluhm and scientist Ian MacPherson,
of the National Research Council of Canada, discuss the grid patterns they will fly. The
boom extending from the nose of their Twin Otter measures wind direction during flight.


feet long, did the work of what
would otherwise have been a large,
heavy antenna. "The ESTAR sensors
were the core of the experiments,
and they worked," he says.
ESTAR uses a microwave band
frequency that is more suitable for


measuring soil moisture," says
Jackson. "A preliminary review of
the data shows a remarkable match
between air and ground data, con-
vincing me beyond a shadow of a
doubt that the data will be useful."


Agricultural Research/April 1998





























































NASA is considering using
ESTAR on satellites, possibly
making a decision as early as this
year. It is an alternative to the
AMSR, or Advanced Microwave
Scanning Radiometer, which is
similar to the sensors tested aboard


Mir and the radar satellites. The
AMSR will be used by a NASA
satellite planned for launch in 2000
and by the Japanese ADEOS II, also
planned for launch in 2000.
By around 11 o'clock each night,
Jackson's NASA colleague Ann Hsu


had posted the day's data on the
World Wide Web site created by the
Hydrology Laboratory for the experi-
ment. This site allowed Jackson to
communicate with participants in the
experiment-even before they
arrived from around the world.

Website Open to All
Once the experiment began, the
entire team-on site at various
locations in Oklahoma-used the
web to review the data each night and
make plans for the next day.
Jackson says that one of the ways
the SGP97 project differed from the
smaller, earlier tests at Walnut Gulch
and Little Washita was the dramatic
increase in e-mail and World Wide
Web use.
In fact, anyone can view various
aspects of the experiment on that
website, including preliminary data
prepared for the public. (Go to http://
hydrolab.arsusda.gov/sgp97) The
experiment's results will be presented
at the American Geophysical Union
meeting during May 1998. Research-
ers will publicly share all data in
September on a to-be-announced
NASA web site.
This past December, Jackson
learned that the Mir space station had
resumed collecting data over Oklaho-
ma. He won't need to go to Oklaho-
ma this June to verify the data. He's
glad that with last summer's work,
scientists around the world will be
able to process satellite data for years
to come-without crawling on their
hands and knees with buckets and
soil spatulas.-By Don Comis, ARS.
Thomas J. Jackson and William P.
Kustas are at the USDA-ARS Hydrol-
ogy Laboratory, Bldg. 007, 10300
Baltimore Ave., Beltsville, MD
20705-2350; phone (301) 504-8511,
fax (301) 504-8931, e-mail
tjackson @hydrolab.arsusda.gov
bkustas@hydrolab.arsusda.gov *


Agricultural Research/April 1998













Soil scientists have at least one
thing in common with stock-
brokers: Both deal with sub-
jects so complex they often
seem unmanageable. It should be no
surprise that both are turning to a
mathematics of chaos-for solutions.
The mathematician Benoit Man-
delbrot is largely responsible for the
current interest in fractal geometry, a
math that shows the irregular shapes
of nature. He first attempted to use it
to master the commodities market in
the 1950s. In the early 1960s, he
went on to work for IBM, where he
developed the computer power that
fuels today's fractal frenzy.
Fractal geometry is particularly
suited to advanced computer graphics
packages. It has gained widespread
attention of soil scientists and agrono-
mists over the past decade. For fractal
geometry may open a gate in a wall
many of them run into as they gather
data on several different scales.
It used to be that soil scientists
interested in soil hydrology gathered
data only on a small scale-either 2-
by 2-inch soil samples for lab studies
or 6- by 6-foot plots in the field, says
Yakov Pachepsky. He is an Agricul-
tural Research Service cooperating
soil scientist from Duke University in
Durham, North Carolina.
"But that approach was 20 years
ago," says Pachepsky, who is cur-
rently located at the ARS Remote
Sensing and Modeling Laboratory in
Beltsville, Maryland.
"Now, with precision agriculture,
we are asked to deal with combine-
mounted yield monitors that churn
out data on about 20-square-yard
grids as fast as the farmer's combine
crosses the field," he says. "And
satellites send images of Earth on
grids of a square mile or more.
"We'll be out of business if we
can't relate data between all these
scales. Fractal geometry offers the
potential of bridging them."


Soil scientist Yakov Pachepsky (left) and hydrologist Walter Rawls examine soil samples
from fields where yields and soil pore geometry are different. The ability of soils to retain
and transport water is closely related to fractal parameters of pore space.



Fractals-A Bridge to the


Future for Soil Science


Fractal geometry gets its name
from the irregular fragments it deals
with. It is scale-independent, which
means that a basic shape stays the
same-along with any objective
measurements of it-no matter how
much you enlarge or reduce the size
of its image.
Traditional measurements are
made in dimensions of line, area,
volume, or mass. Fractal dimensions
range from 1 for a straight line to
almost 2 for a chaotic, unpredictable


squiggle-like a day of extreme
highs and lows on the stock market.

Fractal Dimensions Can Indicate
Plant Stress
In an ARS-funded study, soil sci-
entist Bahman Eghball at the Univer-
sity of Nebraska at Lincoln used frac-
tal geometry to identify corn roots
stressed by lack of nitrogen fertilizer.
He dyed and photographed the roots.
Then he projected the photographic
slides on three different-sized grids.


Agricultural Research/April 1998













fewer grids. The result was a lower
fractal dimension. That dimension,
once fed into a computer graphics
program with a fractal package,
could be used to generate a computer
image of the roots.
Eghball has used the perspective
of fractal geometry to see some
surprising things in the world of
agriculture. For example, by analyz-
ing 60 years of USDA crop yield
statistics-1930 to 1990-he found
that oats and soybeans were the
riskiest crops in terms of having the
most year-to-year yield fluctuations
in response to weather. He also found
that the Green Revolution of the
1950s and 1960s not only raised
yields, but also raised risks of year-
to-year yield variation.


"If one or more roots fell into a
grid, we counted the grid as one
intersected by roots," Eghball says.
By plotting the logarithm of the
number of grids the roots intersected
against the logarithm of grid sizes,
Eghball obtained a line. The slope of
that line is the fractal dimension.
Eghball found this dimension
could be used to spot plant stress.
When corn plants were grown
without nitrogen fertilizer, roots
stopped branching out, intersecting


Eghball ex-
plains that the
comparison of
10 different
crops with wide
variations in
yields was pos-
sible only with
a tool like frac-
tal geometry.
"The fractal
dimension is
unaffected by
the fact that oat
yields are much
lower than corn
or soybean
yields," he
says. "For that
matter, it can
compare


KEITH WELLER (K8035-1)


Thin slices of soil reveal a
pore boundaries. This unev
different magnifications, it
nature of soil pore space. C
helps to both visualize and
differences among pore spa
Surprisingly, pore space ge
be an indicator of soil prod


'apples and oranges'-or a fiber crop
like cotton with a grain crop like
corn. This is possible because we are
comparing patterns of behavior of
objects, not the objects themselves."
Eghball says another strength of
fractal geometry is its ability to
determine if a phenomenon is
predictable. Generally, a fractal
dimension close to 1 means it is more


predictable. So rice yield (1.2) is
more predictable than oat (1.47) or
soybean (1.45) yields.

Fractals and the Chaos of Spatial
Variability
One of the chaotic messes in the
agronomy world is what scientists
call spatial variability. That is,
whatever you talk about in a farm
field-crop yield, erosion, soil
moisture, soil temperature, drainage,
waterflow, chemical movement, soil
fertility-all can vary widely, even in
a space as small as 10 feet. So how
can we extrapolate to thousands of
acres of land without costly measure-
ments every few feet or so?
Laj Ahuja wants to see if fractal
analysis can help. He uses it to
quantify spatial
variability so it
can be plugged
into computer
models at his
Fort Collins,
Colorado,
research unit.
The models do
not currently
account for this
realm of jagged variability.
venness is similar at "Precision
dictating the fractal farming has an
computerr software interest in
quantify
aces in soils. quantifying and
ometry appears to mapping this
activity. spatial variabili-
ty on landscapes
so farmers can
manage different
parts differently," says Ahuja, who
heads ARS' Great Plains System
Research Unit in Fort Collins.
With the help of ARS colleagues
and scientists at Colorado State
University, Ahuja is trying to bridge
plot, field, and farm scales so he can
predict these processes across entire
watersheds encompassing many
farms and ranches.


Agricultural Research/April 1998






BAHMAN EGHBALL (K8037-1)


This corn plant was groMwn in a woodenn
box containing meal pegs so its root-
branching pattern could be studied. Soil
has been removed to expose the roots.

Far left: Scientists can project a photo-
graph of a plant's root system onto grids
of different sizes and count the number of
root intersects within each grid. B) plot-
ting the logarithm of the number of
intersected grids against the logarithm of
grid sizes, a line is obtained, the negative
slope of which is the fractal dimension.
Scientists can use this dimension to spot
plant stress.


Pachepsky and microbiologist
Lawrence J. Sikora at Beltsville,
working with soil scientist Martin
Rabenhorst at the nearby University
of Maryland at College Park, want to
use fractal dimensions of physical
aspects of soil-such as the volume
and inner surface roughness of soil
pores-to characterize soil quality
relative to its ability to grow plants.
"These are easy-to-measure char-
acteristics," Pachepsky says. The sci-
entists make their measurements
from thinly sliced sheets of soil sam-
ples, the structure of which is pre-
served by the addition of resin.
Walter J. Rawls, who heads Belts-
ville's ARS Hydrology Laboratory, is
working with soil scientist Raymond
R. Allmaras at St. Paul, Minnesota,
and others to predict soil water
movement based on these pore
measurements, along with


measurements of the soil's density
and ability to hold water. They use
fractal geometry to relate difficult-to-
measure soil hydraulic properties to
other soil variables readily available
from soil surveys.
Soil scientist Jerry C. Ritchie, who
is also with the Hydrology Labora-
tory, uses fractal geometry to analyze
heights of range plants traced by air-
borne lasers. The heights reveal vege-
tation type-grass, shrub, or transi-
tion zone from grass to shrub. Vege-
tation type is important to predicting
soil moisture, because it affects
roughness of land surface. The
roughness influences windspeed
which in turn greatly affects evapora-
tion of water from soil and water up-
take by plants.
G. LeRoy Hahn, former head of
the Biological Engineering Research
Unit at the U.S. Meat Animal Re-


search Center at Clay Center, Ne-
braska, and his colleagues Roger
Eigenberg and John A. Nienaber
used fractal geometry with cattle
body temperatures to determine that
steers begin to suffer heat stress
when the air temperature reaches
770F. Hahn recently retired but con-
tinues his work as a collaborator.
Yud-Ren Chen, who was in
charge of the unit at Clay Center
before Hahn, also contributed to the
animal stress study. Chen found
mathematical equations to compute
the fractal dimensions of animal
temperatures. He now heads the
ARS Instrumentation and Sensing
Laboratory in Beltsville.
One study was done with six
young steers kept in indoor stalls.
Sensors in their ear canals automati-
cally recorded their temperatures ev-
ery 30 seconds for at least 2 weeks,


Agricultural Research/April 1998













while their stalls ranged from a cool
390F to 630F to a hot 800F to 1050F.
By comparing body temperature
fluctuations in the hot and cool cham-
bers, the scientists calculated the
fractal dimension. It stayed level at
1.7 until the air temperature reached
770F. After that, the dimension
dropped precipitously to 1.2, indicat-
ing that the steers were so heat-
stressed they could no longer control
their temperatures.
Hahn says that fractal analysis pro-
vided a way to assign a number to the
degree of fluctuation in body temper-
ature. As the chamber became too
warm, the steers became stressed and
their temperatures fluctuated less,
making the fractal dimension lower.
"They were losing their ability to reg-
ulate their temperatures. Normally,
cows, like people, have marked, ran-
dom fluctuations in body tempera-
ture," Hahn says.
Hahn and Nienaber have since
done similar experiments with sheep
and pigs.
"Using the fractal dimension of
1.7 as a stress threshold, we can now
tell feedlot managers that it's best to
turn on their sprinklers when the air
temperature approaches 800F," Hahn
says. "We've found this stress thresh-
old correlates well with temperatures
at which steers begin to lose interest
in feeding."
Hahn also says that observations
of individual steers with higher tem-
perature thresholds raise the possibil-
ity of using the stress threshold to
help breed more heat-tolerant cattle.
Whether data collection is done
with livestock or with landscapes, up
close or far away, the agricultural re-
search world is finding that fractal
geometry may be a way to find order
in chaos.-By Don Comis, ARS.
Yakov Pachepsky is at the USDA-
ARS Remote Sensing and Modeling
Laboratory, Bldg. 007, 10300 Balti-
more Ave., Beltsville, MD 20705-


2350; phone (301) 504-7468, fax
(301) 504-5823, e-mail
ypacheps @ asrr.arsusda.gov
Bahman Eghball is in the USDA-
ARS Soil and Water Conservation Re-
search Unit, University of Nebraska,
119 Keim Hall, Lincoln, NE 68583-
0934; phone (402) 472-0741, fax
(402) 472-0516, e-mail
beghball@unlinfo.unl.edu
Lajpat R. Ahuja is in the USDA-
ARS Great Plains Systems Research
Unit, P.O. Box E, Fort Collins, CO
80522-0470; phone (970) 490-8315,
fax (970) 490-8310, e-mail
ahuja @gpsr.colostate.edu
Lawrence J. Sikora is at the USDA-
ARS Soil Microbial Systems Laborato-
ry, Bldg. 318, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-9384, fax (301) 504-8370,
e-mail lsikora@asrr.arsusda.gov
Raymond R. Allmaras is in the
USDA-ARS Soil and Water Manage-
ment Research Unit, University of
Minnesota, 439 Borlaug Hall, St.
Paul, MN 55108; phone (612) 625-
1742, fax (612) 649-5175, e-mail
allmarasl@soils.umn.edu
Walter J. Rawls and Jerry C. Ritch-
ie are at the USDA-ARS Hydrology
Laboratory, Bldg. 007, 10300 Balti-
more Ave., Beltsville, MD 20705-
2350; phone (301) 504-7490, fax
(301) 504-8931, e-mail
wrawls @ hydrolab.arsusda.gov
ritchie @ hydrolab.arsusda.gov
John A. Nienaber, G. LeRoy Hahn,
and Roger A. Eigenberg are at the
USDA-ARS U.S. Meat Animal Re-
search Center, P.O. Box 166, Clay
Center, NE 68933-0166; phone (402)
762-4270, fax (402) 762-4273, e-mail
nienaber@email.marc.usda.gov
Yud-Ren Chen is at the USDA-ARS
Instrumentation and Sensing Labora-
tory, Bldg. 303, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-8450, fax (301) 504-9466,
e-mail ychen@asrr.arsusda.gov *


A Geometric
Language for the
Universe?
Fractals are being used for
everything from A to Z today.
including:

Astronomy-describing the
Big Bang; climate change
predictions
Branching in tree cro\w ns,
roots, and mycelium
Clouds-formation and
development
DNA mapping
Erosional processes
Flow in natural porous media
Fracturing-predictive
models
Graphic data compression
Hydrology of breathing rivers
High ay traffic analysis
Human health-analyzing
brain wa\es, heartbeats,
other body rhythms;
diagnosing disorders
Image analN sis and storage
Jaggedness of natural bound-
aries
Kinetics of chemical reactions
Landscape diversity
Nlo\ ies-special effects
Noise-modeling
Oil exploration
Optical devices
Pattern recognition
Polymers-adsorption and
interactions
Quantum theory
Remote sensing-data
interpretation
Simulation of terrains
Stock markets-trends and
variations
Temperature fluctuations
Underwater exploration
Visual computer tools for
graphics
Zoology-animal behavior:
population dynamics


Agricultural Research/April 1998
























ii, i


"1 0













Z. IL
.4













































Research instructor Roman Shypailo uses
dual-energy v-ra3 ahsorpliometr% to
measure the bod) fat and bone mineral
densiI. or U.S. Arm3 major Mlaureen
Barihen. before pregnancy .
-DU L .ILLIIrU.1 iVoU .1 1


: ^
,. .: ,' ~ 11
: ',. : ",













From

Mothers

in the

Military






I f a female soldier decides to
have a child, how quickly will
she be ready to return to duty?
Women in the military are expect-
ed to maintain a trim appearance.
And the military requires all members
to pass periodic weight, body fat, and
fitness tests. Current military regula-
tions give women 6 months after
delivery to meet those requirements.
Is that a reasonable expectation?
The U.S. Department of Defense is
financing a study at the Children's
Nutrition Research Center in Hous-
ton, Texas, to learn exactly what
women can expect from their bodies
before, during, and after pregnancy. It
will also address when the military
can expect women to return to duty
readiness. The research facility is run
jointly by Baylor College of Medi-
cine and USDA's Agricultural
Research Service.
"This research project, one of the
most comprehensive of its kind, will
follow 68 military and civilian
women's pregnancies," says nutri-
tionist Nancy F. Butte, who leads the
study. "Researchers will use the latest
scientific tools to assess their calorie
needs, body composition, and physi-
cal ability."
"Very few studies examine what's
happening during pregnancy with this


level of complexity, and most do not
include pre-pregnancy data," says
lactation physiologist Judy M.
Hopkinson. "By including before-
and-after data, we will be able to see
changes that other studies beginning
at 8 to 10 weeks of gestation may
have missed."
The researchers will be using four
component models to estimate body
composition. These models combine
several different measurements to
calculate body fat. Simpler models of
body composition use fewer mea-
surements and require more assump-
tions about the body. But some of
those assumptions may not be valid
during pregnancy. By combining
techniques to measure components of
the body, assumptions can be avoid-
ed, resulting in greater accuracy.
For example, fat mass and body
density can be calculated by
hydrodensitometry-that is, by
weighing a woman in and out
of a tank of water. This
technique assumes a
certain portion of lean
tissue is water-a
problem, since
the water
content of
lean tissue
increases
during
preg-
nan-
cy.


Researchers compensate by
adding another test. They give the
women water tagged with a safe,
nonradioactive form of hydrogen.
This allows researchers to measure
the total amount of water in the body.
By combining data on body density
and total body water, they obtain a
more accurate estimate of body fat.

Measuring Total Calorie Use
The researchers also use doubly
labeled water tagged with nonradio-
active forms of both hydrogen and
oxygen to make precise measure-
ments of caloric expenditure. The
volunteers drink the labeled water,
and for 14 days, they provide saliva
samples. The rate at which hydrogen
and oxygen disappear from the body
as water or carbon dioxide gives
investigators an estimate of how
many calories a woman uses. This
works because burning food
calories uses oxygen and
gives off carbon dioxide.
Each woman spends 24
hours in one of the
research center's four
state-of-the-art whole-
room calorimeters. These
look like small hotel
Rooms complete
with


Agricultural Research/April 1998













television, bed, bathroom, and a
treadmill. Such rooms are designed
to estimate energy expenditure from
very precise measurements of
oxygen consumption and carbon
dioxide. By comparing data from the
doubly labeled water and the calo-
rimeter, scientists can estimate how
much energy each woman uses for
physical activity.
Dietitian Caryn Honig completed
the study on May 13, 1997,
when her second daughter,
ADAM G
Natasha, was 6 months old.
Honig, 32, works at the Texas
Children's Hospital, where
she counsels young people
with special dietary needs.
"In the first trimester, I
burned more calories than in
pre-pregnancy; in the second, .
even more; and in the third,
still more," says Honig. "After ,
Natasha was born, I went back
to my pre-pregnancy levels-
almost to the calorie. For me,
this reinforced how important Whil
it is to get enough to eat lieute
during pregnancy." walk
The center researchers are
also looking at how pregnancy
affects body protein, muscle strength,
and bone mass. They use dual-energy
x-ray absorptiometry (DEXA) before
pregnancy and 2 weeks and 6 months
after delivery. The instrument
provides a three-component (bone,
lean tissue, and fat) analysis of the
body using safe, ultralow levels of x-
rays. To protect the fetus, it's not
used during pregnancy. What is
learned may help settle some scien-
tific disputes.
"Some studies show bone is lost
during pregnancy, but others suggest
that it doesn't change-or even
increases," says Hopkinson. "We
want to look at the net effect of
pregnancy on bone mineral content."
But what about protein, the main
component of muscle tissue? Re-


searchers measure total body nitro-
gen, a key part of those proteins,
before and just after pregnancy and
again 6 months later. Exercise
physiologist Margarita Treuth uses a
series of strength and exercise tests to
obtain a comprehensive picture of the
effect of pregnancy and how quickly
women return to pre-pregnancy
status.
This information will be used to
evaluate whether the military's


e study coordinator Carolyn Heinz observes, U.S. Ai
nant Regina McWilliams, at 6 months after delivery
s a treadmill inside a respiration calorimeter.


standards for body weight and the
requirement for weight gain during
pregnancy are compatible.

Determining a Desirable BMI
The military body weight standard
is based on a person's body mass
index. This is calculated by dividing
body weight in kilograms by the
square of a person's height in meters.
A woman at 5 feet 5 inches can
weigh no more than 144 pounds, to
meet the military standard of a BMI
of 24.
"Pre-pregnancy BMI is a determi-
nant of fetal growth," says Butte.
"The recommended weight gain in
women with a low BMI (below 19.8)
is higher than for women with
average or above-average BMIs. But


we don't know which part of that
compensating gain is benefiting the
fetus. Is it gains in fat, free fat mass,
or water? It may be there's a thresh-
old for maternal fat below which fetal
growth is compromised. That's one
reason we need a better physiological
model of pregnancy," she says.
The four-component model and the
expertise of Butte's research team
have already identified an error in the
equation the military uses to
calculate fat mass. Military
equations, based on body
circumference measurements,
underestimate fat mass. The
margin of error is greater in
heavier women.
How do the military women
feel about this study?
Major Maureen Barthen, 36,
a military reservist for 3 years,
1i-| is at the pre-conception stage.
SShe works at the 75th Army
A Division in Houston, Texas,
a evaluating her unit's wartime
my readiness. At home, she's the
y, mother of 6-year-old Frances
and Amelia, a 4-year-old.
"I'm really excited about
the study," says Barthen, "I
want to learn more about my body's
changes in pregnancy. This is not just
because I'm in the reserves. Being fit
is part of staying healthy."
This research will benefit not only
military women like Barthen, but also
all women concerned about regaining
fitness after their babies are born.-
By Jill Lee, ARS.
Nancy F. Butte and Judy M.
Hopkinson are at the Children's
Nutrition Research Center, Baylor
College of Medicine, 1100 Bates St.,
Houston, TX 77030-2600; phone
[Butte] (713) 798-7179, fax (713)
798-7187, e-mail
nbutte @ bcm.tmc.edu
[Hopkinson] (713) 798-7008, fax
(713) 798-7098, e-mail
judyh@bcm.tmc.edu *


Agricultural Research/April 1998































A field ot sattlower, Carthamus tinctorius L.


Afield of safflower in full
bloom casts a beautiful yel-
low glow across the western
Great Plains. But to farmers, safflow-
ers' best features are underground.
An oilseed, safflower could be a
high-value rotation crop-a crop
planted every 2 to 4 years-for wheat
farmers using no-till or conservation
tillage, say Agricultural Research Ser-
vice soil scientists Donald Tanaka and
Steve Merrill. They work in the Natu-
ral Resources Management Research
Unit at Mandan, North Dakota.
No-till farming systems use no till-
age, or very reduced amounts, to pre-
serve the natural organic content of
the soil. Wheat growers rely on crop
rotation to disrupt the life cycles of in-
sect pests, weeds, and diseases.
Tanaka says safflower may be a
good alternative because its deep roots
take up water and nutrients that are
out of reach of other crops.
Safflower has been cultivated on
other continents for centuries, but it
has been planted in the United States
only since the 1950s. Its seeds can be
processed for cooking oil or sold for
high-quality bird food.


Tanaka says farmers began plant-
ing more safflower in the western
plains in the early 1980s, but it didn't
do well in heavily tilled fields. The
switch to conservation tillage in re-
cent years has encouraged production.
"Safflower is best suited to dry,
temperate climates such as those in
North Dakota, Nebraska, eastern
Montana, and other areas of the west-
ern Great Plains," Tanaka says.
"It does better in no-till or
minimum-till systems because the
seeds can be planted closer to the soil
surface. Also, the higher moisture
content of no-till fields favors germi-
nation and stand establishment. Saf-
flower is particularly suited to our
area of the country."
Research conducted by Merrill
shows that safflower roots descend up
to 7 feet and can tap water and nutri-
ents deep underground, in subsoil.
"Wheat and other cereal grains, like
oats, can typically reach about 4 feet
down into the soil profile," he says.
And another plus: "Safflower's
deeper roots can reach fertilizer that
may have leached below the root
zone of other crops," says Merrill.


ARS research shows up to 50 per-
cent less nitrate in the soil in years
when safflower was planted in rota-
tion with wheat. Nitrate is another
form of nitrogen, an important nutri-
ent to crops.
"By using safflower in a crop rota-
tion, you prevent movement of nitrate
into the groundwater because the ni-
trogen is being used to produce
seeds," says Tanaka. "And when the
plant removes water from the subsoil,
lost nutrients are used by the plant and
don't move toward the groundwater."
Safflower also encourages carbon
sequestration, a process in which
plants remove carbon dioxide from the
atmosphere. More research is needed
to learn how much carbon is absorbed
and transferred to the soil.-By Dawn
Lyons-Johnson, ARS.
Donald L. Tanaka and Stephen D.
Merrill are in the USDA-ARS Natural
Resources Management Research
Unit, Northern Great Plains Research
Laboratory, P.O. Box 459, Mandan,
ND 58554; phone (701) 663-6445, fax
(701) 667-3054, e-mail
tanakad@mandan.ars.usda.gov
merrills@mandan.ars.usda. ov *


Agricultural Research/April 1998















































Iif







.'.




4~L













ancient medical texts, some
dating back to the early
Greeks, talk about medici-
nal plants. Now modern science-
including some done by USDA's
Agricultural Research Service-is
taking this ancient art to new levels.
Plant physiologist Stephen O.
Duke heads ARS' Natural Products
Utilization Research Unit at Oxford,
Mississippi. Part of his research
involves discovering how plants
make their beneficial compounds and
how to better extract them.
One example of his work is
understanding the plant known as
annual wormwood, Artemisia annua.
This gray-green aromatic plant and
its relatives in the genus Artemisia
have been used to make absinthe and
flavored wines since earliest times.
Now this plant family could bring a
new gift: Its natural pest-fighting
defense may protect humans from
malaria.
It's no secret that malaria-fighting
drugs have done a lot for civiliza-
tion-the Panama canal is one
testimony of their success. But what
happens when the organisms that
cause the disease develop resistance
to current treatments?
Right now, scientists are preparing
to solve this problem before it ever
occurs by having alternative treat-
ments ready. One of these under-
study cures could be artemisinin, a
natural compound produced by
Artemisia plants.
Medical researchers, especially in
the military, want to know more
about wormwood's malaria-fighting
properties. That's because when duty
calls U.S. troops to a tropical area,
the disease is always a potential
problem.
The question Duke wants to
answer is exactly how the plant
produces this potentially life-saving
compound. Knowing the physiology


would play a role in increasing the
supply of this beneficial compound.
"It was already known that worm-
wood has little balloonlike glands on
its leaf surface," Duke says. "We
found that as the plant matures, these
balloons fill with artemisinin. Pest
protection is nature's goal. As the
plant matures, the glands swell bigger
and finally burst, covering the plant
with self-made pesticide."
It is the natural pesticide aspect of
annual wormwood that brings it even
more within Duke's expertise. His
research group's primary mission is
to find natural products to control
agriculture pests-especially in
America's secondary crops.
There's money to be made in
fighting pests, but it's mainly in
protecting the nation's agronomic
superstars-corn, wheat, and soy-
beans. That can mean that important,
but less prominent, crops such as
avocados and orchids are ripe for new
protective treatments.
The scientists in Duke's research
unit search the plant and microbial
kingdoms for pest-fighters that work
in harmony with the environment.
Artemisinin, for
example, may also
yield its protective SCOT BAUER (K80'
powers to otherwise
vulnerable crops. .
"We found that i
without the genetic
coding for the gland,
Artemisia won't -
produce artemisinin," l
says Duke. "For the
plant, it's essential to
have the genetic
instructions for both
the toxin and the
storage mechanism."
Knowing how a
plant's DNA programs Chemist Agne
it for pest protection Duke use stea
content of wor
may lead researchers
to ways to provide the


same pest resistance to currently
vulnerable plants.

Products for People Too
Besides the crop protection
aspects of their research, Duke and
his team of scientists are also looking
at the pharmaceutical value of these
plants. In fact, Artemisia is just one
of the plants they're exploring.
Another plant that's intrigued
Duke is St. John's-wort, which
belongs to the genus Hypericum.
Greek texts dating back to 2000 B.C.
have noted uses and harvesting
techniques for this plant. Currently,
its claim to fame is as an alternative
treatment for depression.
"St. John's-wort is the preferred
treatment for mild depression in
Europe," says Duke. "Physicians
there choose it four to five times
more often than synthetic drugs
because they believe it has fewer side
effects. Europeans get their supply
from Albania, but it grows wild in
the United States."
Much to the chagrin of ranchers
who know St. John's-wort as a pest,
horses and cattle that eat the plant


s Rimando and plant physiologist Stephen
m distillation to determine the essential oil
mwood leaves.


Agricultural Research/April 1998













develop a sensitivity to light, result-
ing in a rash, Duke says. Understand-
ing the biochemistry involved might
help reduce the effects.
But now, however, Duke's main
concern is extracting a red pigment
from the plant to benefit people.
St. John's-wort tablets are stan-
dardized by the amount of the red
pigment, called hypericin, which
some researchers suspect is the active
ingredient. Hypericin is being studied
as both an anti-viral and anti-cancer
drug.
St. John's-wort has yet to receive
FDA approval for use as a treatment
for depression in the United States.
But several companies are doing
phase I and II clinical trials, a step
toward gaining approval. Currently,
Americans can buy St. John's-wort as
a diet supplement.

Getting the Good Stuff Out
Finding an economical extraction
method for hypericin would be


A highly effective chloroform dip
procedure enables plant biotechnologist
Camilo Canel to extract over 90 percent of
artemisinin from the glandular hairs of
wormwood leaves.


helpful in developing St. John's-
wort both for medicinal purposes
and as an anti-viral agent. Since
plant extraction and physiology are
aspects of Duke's work, he began
with research on the plant.
It was already known that hyperi-
cin was concentrated in small black
and red dots found on the flowers


MARY DUKE (K8027-20)
U.AL .- o._ A a


Microscopic view of a hypericin-containing gland of St. John's-wort, Hypericum
punctatum.


and leaves of St. John's-wort and that
it was effective in pest control. But
hypericin, if given in a high enough
concentration, is toxic to all living
things, including St. John's-wort. The
plant protects itself by sealing the
hypericin dots off with a thin cell
layer.
Normally, hypericin is extracted
by chopping the plant up and extract-
ing it with ethanol. But Duke may
have a better way.
"The plant has other enzymes that
can destroy hypericin when the cells
containing the toxin are breached," he
says. "Crushing the plant releases
these hypericin-destroying proteins,
defeating your purpose. We are look-
ing at chemical extraction methods
that may work better-like soaking
the leaves in a solution that gently re-
moves the hypericin without having
to cut them."
While breeders and pharmaceutical
companies are waiting to see what
this plant can do, they can also stay
tuned to Duke's research team.
Already these scientists are hot on the
trail of new helpful plants and better
extraction techniques. Last fall, Duke
had just finished completing his
staffing, and the scientists were busy
ordering equipment to start new
research projects.
"All I can say is we are excited
about the new research projects
we've begun, and we're always
looking for new ideas," says Duke.
"We hope to excel in this new-and
yet ancient-field of natural pesti-
cides and pharmaceuticals."-By Jill
Lee, ARS.
Stephen O. Duke is in the USDA-
ARS Natural Products Utilization
Research Unit, National Center for
the Development of Natural Products,
Room 1011, University of Missis-
sippi, Oxford, MS 38677; phone
(601) 232-1036, fax (601) 232-7062,
e-mail sduke@ag.gov *


Agricultural Research/April 1998








Better Cold-Weather Starts for

Biodiesel Fuel


A anyone who has tried
starting a car on a frigid
January morning will
appreciate the efforts of Agricultural
Research Service (ARS) scientists at
the National Center for Agricultural
Utilization Research in Peoria,
Illinois. They have improved bio-
diesel's ability to start up engines in
cold weather.
The research is good news for
soybean farmers because it will speed
the commercial use of biodiesel fuels
made from soybean oil.
When overnight temperatures fall
near or below freezing, biodiesel
fuels form small, solid, waxy crystals
that stick together to form bigger
ones. These larger crystals block fuel
filters and plug fuel lines.
To solve this problem, ARS
chemical engineer Robert O. Dunn
has developed a three-step winteriza-
tion process that involves mixing in
additives, chilling the fuel, and
filtering out solids. In laboratory
tests, researchers have produced
biodiesel fuels capable of starting
engines at temperatures as low as
5F, making them comparable to
petroleum-based diesel fuels.
"Using additives makes the fuel
easier to pour," says Dunn. Other
researchers have tried to winterize
biodiesel fuels without additives, but
they found that to significantly
improve the cold flow properties,
they had to remove 70 percent of the
starting material.
"That was like throwing out the
baby with the bath water," says
Dunn. "Our technique produces 80
percent liquid fuel. The remaining 20
percent solids can be stored and used
as fuel in warmer weather."


There is still one problem the
researchers are trying to resolve:
Winterizing causes changes in the
makeup of biodiesel fuels that lead to
a lower cetane number-as well as a
decreased stability during long-term
storage that the scientists are also
trying to improve.
The cetane number, which is
similar to the octane number of
gasoline, is one important way to
measure biodiesel fuel quality.
"Unfortunately, harmful exhaust
emissions, especially nitrogen oxides,
may be expected with a lower cetane
number," says chemist ARS Gerhard
H. Knothe, who is also trying to
enhance the quality of biodiesel fuels.
He's developing new cetane improv-
ers that will help the biodiesel fuels
burn faster. With faster burning fuels
and lower nitrogen oxide emissions,
less pollution by ozone may be
possible.
Research efforts like these can
help put biodiesel fuels in city buses,
in government and industry fleet cars,
and in heavy equipment used in
underground mining operations.
These vehicles are among the first in
the nation to test and pave the way
for continued acceptance of biodiesel
as an alternative fuel or as a fuel
extender for mixing with standard
petroleum diesel fuels. The federal
Energy Policy Act requires 75
percent of all new state and federal
vehicles to be fitted for alternative
fuels by the year 2001.
According to a Department of
Energy publication, the United States
spends about $60 billion a year to
import 50 percent of its oil. Since the
early 1980s, domestic oil production
has declined, reducing U.S. employ-
ment in this industry.
The ARS research can help jump-
start the adoption of biodiesel in
snow-removal trucks and in city
buses. The use of biodiesel fuels in


Chemical engineer Robert Dunn inspects
chilled fuels that have been winterized for
better engine start-ups in cold weather.
The clear fuel on the right will ignite more
effectively than the cloudy one.


all U.S. city buses would require oil
from 43 million bushels of soybeans
annually. There are enough niche
markets for biodiesel to make plenty
of profits for the nation's 400,000
soybean growers.-By Linda Cooke
McGraw, ARS.
Robert O. Dunn and Gerhard H.
Knothe are in the USDA-ARS Oil
Chemical Research Unit, National
Center for Agricultural Utilization
Research, 1815 N. University St.,
Peoria, IL; phone (309) 681-6531,
fax (309) 681-6340, e-mail
dunnro @ mail. ncaur. usda. gov
knothegh@mail.ncaur.usda.gov *


Agricultural Research/April 1998


I(F(TU WEIIE~ ll(lm04-11







Hard-To-Control Weeds Need

a Mix of Measures


F armers and land managers
will have to become profi-
cient at long-range planning
for weed control-and also learn to
use a mix of different techniques-to
control weeds, say Agricultural
Research Service scientists.
Hemp dogbane, waterhemp, leafy
spurge, cocklebur, and thistle are
becoming more difficult to control
with one-step approaches such as
using a single tillage method, annual
crop rotations, or seasonal herbicide
applications. The ARS scientists
advocate use of integrated weed
management systems that increase
cost efficiency for farmers, promote
more ecologically sustainable produc-
tion, and conserve soil and water
resources.
Weeds and weed control cost U.S.
farmers about $15 billion each year.
Part of the problem is that the
long-term use of specific herbicides
has led to development of weeds with
herbicide resistance. Another prob-
lem is that shifts in tillage practices
make it easier for different types of
weeds to get established. And some
cropping patterns have discouraged
competition among weed species,
causing certain ones to spread and
crowd out crops.
One scientist tackling weed
problems in new ways is ARS range
scientist Robert A. Masters. He is in
the ARS Wheat, Sorghum, and
Forage Research Unit at Lincoln,
Nebraska.
Masters has combined herbicides,
controlled burning, and replanting of
native warm-season grasses-without
tillage-to supplant leafy spurge, a
noxious weed that threatens Northern
Plains grasslands.
"The productive capacity of Great
Plains grasslands has been reduced
greatly by invasive weeds like leafy
spurge," he says. "These weeds have
displaced desirable native forages as
well."


Leafy spurge was intro-
duced into the north-
ern Great Plains from a
Eurasia in the late
1800s. It has no natural
enemies in this country,
and herbicides provide
only short-term control.
Unlike sheep and goats,
cattle and horses won't
graze land infested with
leafy spurge, and they avoid
eating forage grasses growing
next to the weed.
In field tests conducted
between 1992 and 1995 in
cooperation with scientists at the
University of Nebraska, Masters
applied a three-pronged strategy to
fight leafy spurge. The result was a
60-percent reduction in spurge
populations and a surge in produc-
tion of warm-season grasses.
First, Masters applied a combina-
tion of the herbicides Arsenal and
Oust to kill leafy spurge plants in the
fall. He burned the dead plant residue
the following spring. Then he planted
native prairie species such as big
bluestem, switchgrass, and indian-
grass.
"Two years
after planting,"
says Masters, ROBERT MASTERS (K804
"switchgrass and
bluestem hay
yields increased to
over 4,000 pounds
per acre, and
indiangrass
produced more
than 3,000.
"Our goal is to
develop economi-
cal, integrated
weed management
strategies that
enable land
managers to To prepare a site
tillage, scientists
convert marginal burning in the sp
herbicide treatm


Early growth stage of water-
hemp, a weed that is becoming
resistant to certain herbicides.


1-1)


for planting native storage grasses without
in Lincoln, Nebraska, practice controlled
Hiring to remove plant residue remaining after
ents killed weeds the preceding autumn.


Agricultural Research/April 1998







DOUG BUHLER (K8042-1)


Continuous production of corn and soybeans cr
environment favorable to weeds such as giant fi
beginning to choke out the corn on the right. TI
left has been treated with a postemergence herb
the corn from competition.


cropland and degraded grasslands to
high-value grasslands that are
resistant to noxious weed invasion,"
he says. "In our current research,
we're refining this strategy by using
a combination of the herbicides
Plateau and Roundup, in place of
Arsenal and Oust, to promote
establishment of mixtures of
native grasses and legumes."
Loyd Wax, an agronomist at
the ARS Crop Protection
Research Laboratory in Urbana,
Illinois, is taking a similar approach
to thwart waterhemp, a species
similar to redroot and smart pigweed.
Waterhemp biotypes have become
increasingly resistant to ALS-
inhibiting herbicides that block
production of branched-chain amino
acids, the building blocks of protein.
Wax found super-resistant water-
hemp biotypes that withstood up to
520 times the labeled rate of certain
ALS-inhibiting herbicides.
To combat these ALS-resistant
biotypes, Wax conducted studies
showing that growers could mark-
edly improve waterhemp control by
combining non-ALS-inhibiting
herbicides with cultivation. This
strategy affords the grower two very
different methods to control ALS-
resistant waterhemp populations.
"We controlled established
waterhemp populations with non-
ALS herbicides and then tilled the


soil at a depth that
was not favorable to
waterhemp seed
germination and
emergence," says
Wax.
"We also found
eates an that we could
oxtail, which is combine sequential
ie foxtail on the applications of non-
,icide, relieving ALS-inhibiting
herbicides with the
rapid canopy
closure of close-drill soybeans for
very good waterhemp control in no-
tillage systems," he says.
"Farmers will greatly benefit from
knowing which species of weeds are
established in their fields and using
this information when they plan crop
rotations and farming operations.
They should use a variety of farming
techniques to control weeds. As
farming systems change, weeds and
weed populations change. So farmers
can no longer expect one-shot
solutions to weed problems."

They Fall Into Two Types
Annual weeds are plants that
reproduce by seed and generally
germinate each year to reproduce.
This type of weed includes velvet-
leaf, cocklebur, and foxtail. The
seeds of annual weeds have a better
opportunity to germinate and grow
into mature plants if they are buried
in the soil. Seeds not buried tend not
to germinate.
Perennial weeds regrow each year
from roots or rhizomes-tubal
extensions located below the soil
surface. Perennial weeds include
thistle, quackgrass, and milkweed.
These weeds are usually controlled
by tillage operations such as disking
or cultivating.
A shift in tillage techniques is the
culprit behind changes in the behav-
ior of annual weeds such as velvet-


leaf, cocklebur, and foxtail, according
to ARS agronomist Douglas D.
Buhler of Ames, Iowa. He's seeking
the right balance of tillage and
cropping practices to knock down
both annual weeds and perennials
like thistle, quackgrass, and dogbane.
"Shifts in tillage practices bring
about rapid shifts in weed popula-
tions," Buhler explains.
His research shows the population
of hemp dogbane remained constant
over 14 years when land operators
disked or plowed their soil. Plowing
disturbed the dogbane root systems
and prevented the weed from spread-
ing. When researchers switched to
no-till farming systems on adjacent
acreage-or to systems using no
tillage before planting-dogbane
populations exploded by 400 percent
over the same 14-year period.
On the other hand, no-till tends to
discourage growth of annual weeds
like velvetleaf and cocklebur. Bu-
hler's research showed velvetleaf and
cocklebur thrived in cultivated fields
but were reduced by up to 80 percent
in fields that were not tilled.-By
Dawn Lyons-Johnson, ARS.
Robert A. Masters is in the USDA-
ARS Wheat, Sorghum, and Forage
Research Unit, 344 Keim Hall, P.O.
Box 830937, Lincoln, NE 68583-
0937; phone (402) 472-1546, fax
(402) 472-4020, e-mail
masters @ unlinfo.unl.edu
Loyd Wax is in the USDA-ARS
Crop Protection Unit, N-325 Turner
Hall, University of Illinois, 1102 S.
Goodwin, Urbana, IL 61801; phone
(217) 333-9653, fax (217) 244-7703,
e-mail lwax@uiuc.edu
Douglas D. Buhler is at the
USDA-ARS National Soil Tilth
Laboratory, 2150 Pammel Dr., Ames,
IA 50011-4420; phone (515) 294-
5502, fax (515) 294-8125, e-mail
buhler@nstl.gov *


Agricultural Research/April 1998







Measuring Odors From Livestock

Operations


C complaints about nuisance
livestock odor in rural areas
have become a problem
nationwide. Scientists for the U.S.
Department of Agriculture's Agricul-
tural Research Service are working
to find new ways to tackle the smelly
dilemma.
James A. Zahn, a microbiologist
formerly with the Agricultural
Research Service at the National Soil
Tilth Laboratory in Ames, Iowa,
developed a way to collect air
samples for scientific analysis. He is
now with Iowa State University.
"There is little basic understand-
ing as to what causes the different
odors that are detected around
livestock operations," says Zahn.
"We can't evaluate methods to
control odor until we understand the
makeup of the odors themselves."
Zahn devised a mechanical air-
sampling device that can be trans-
ported to the site where odors


originate. The device uses an absorb-
ing tube and a pump to draw in a
specific quantity of air. To date, Zahn
has identified more than 200 volatile
organic compounds, gases, and
airborne particles from samples taken
near livestock operations.
The most common method of
storing and processing livestock
manure-especially hog manure-is
by storing it in large lagoons or deep
basins. These are anaerobic, or no-
oxygen, environments. There, the
manure breaks down into organic
components including hydrogen
sulfide, acids, ammonia, phenols, and
indoles, which together create the
telltale odor some people call stink.
According to Jerry L. Hatfield,
who leads research at the Ames lab,
the secret to defusing odors is deter-
mining what makes them smelly. So
far, 27 different chemicals that create
hog manure odors have been identi-
fied using Zahn's device. Hatfield


BRUCE FRITZ (K8022-1)


says the laboratory work isn't very
popular. "We can duplicate livestock
manure odors in the lab," he says.
"That doesn't smell very good, but it
gives us clues that we are on the right
track toward understanding how
odors are formed."
The goal of the research, done in
conjunction with the National Pork
Producers Council, is to find ways to
scientifically measure the stink factor
in livestock manure and reduce or
eliminate it.
There is currently no measurable
standard for nuisance odors-only
the human nose. "This isn't a re-
placement for the human nose," says
Hatfield, "but it does give us a
research tool to quickly and objec-
tively assess odors." Older methods
of odor analysis were time consum-
ing, labor intensive, and messy.
The human nose is capable of
discerning only one or two odors at a
time and can be easily overwhelmed
by pungent odors like ammonia, the
gaseous nitrogen compound. Individ-
ual compounds may not be offensive
by themselves, but they could take on
offensive traits when mixed.
Detection is only one component
of the odor problem. Scientists also
monitor weather conditions, air and
ground temperature, and soil condi-
tions in and near hog farm manure
lagoons and pits to learn more about
odor. The results of the research may
lead to improved farm management
practices to keep odors in check.-
By Dawn Lyons Johnson, ARS.
For more information, contact
Jerry L. Hatfield, USDA-ARS Nation-
al Soil Tilth Laboratory, 2150
Pammel Dr., Ames, IA 50011; phone
(515) 294-5723, fax (515) 294-8125,
e-mail hatfield@nstl.gov *


Chemist Dick Pfeiffer uses a gas chromatograph/mass spectrometer to analyze compounds
in odors collected from a swine production facility.


Agricultural Research/April 1998








Transgenic Alfalfa Yields New Products


I imagine a world of well-fed pigs
and poultry without the environ-
mental hazard posed by their
waste.
Such a thought is bringing a smile
to Agricultural Research Service and
University of Wisconsin researchers.
They've joined forces to solve the
pressing animal waste disposal
problem by developing a special type
of alfalfa and a way to harvest its
valuable enzymes. U
ARS agricultural engineer
Richard G. Koegel, who is at
the U.S. Dairy Forage Research
Center in Madison, Wisconsin,
has designed processes to
separate three important compo-
nents from alfalfa.
But this isn't ordinary alfalfa.
It's genetically altered alfalfa
the university researchers
created that yields industrially
valuable enzymes not normally
found in alfalfa.
Phytase is one of these
components. Hog and poultry
producers know the value of
phytase, because it can reduce
the need for costly phosphorus
supplements in rations. Phytase
frees grain-bound phosphorus
so it can be used by nonrumi-
nants such as chickens and pigs.
Improving phosphorus
utilization in these animals can
decrease its excretion in their
manure. Each year in the United
States, hogs and poultry excrete
about 30 million tons of manure Ag
containing 460,000 tons of fro
an
phosphorus, con
Phytase made by fermenta-
tion has been shown to increase
animals' phosphorus uptake by
up to 42 percent. Phytase
extracted from the transgenic
alfalfa is expected to be cheaper than
either traditional supplements or
phytase made by fermentation.


Feed is the most costly part of
raising hogs and poultry, and
phosphorus supplements cost about
$3 per ton of feed. Alfalfa-produced
phytase may cost only half this much.
[For more on phytase, see "Mutant
Corn Has Low Phytic Acid," Agri-
cultural Research, December 1996,
pp. 12-14.]
In addition to phytase, the trans-
genic alfalfa yields proteins and


ricultural engineer Richard Koegel expresses juice
m transgenic alfalfa containing the enzyme phytase
d xanthophyll, as well as proteins suitable for huma
isumption.


xanthophyll-a pigmenting substance
used by the poultry industry to give
yellow color to egg yolks and poultry
skin.
"The equipment used to extract
alfalfa juice isn't terribly complicat-
ed. But it's critical to produce a
uniform, concentrated product
suitable for storage and shipping,"
says Koegel.
"We beat the fresh alfalfa in a mill
with high-speed rotating
hammers to rupture the cell
walls and then pass it through a
continuous press, which ex-
presses juice. Farmer coopera-
tives and commercial livestock-
producing companies are likely
to own this equipment."
Although the equipment
Koegel is now using is station-
ary, he says similar equipment
could be designed for field use.
"We are challenged, though,
to produce a stable, concentrat-
ed product. Xanthophyll
oxidizes and quickly deterio-
rates if not processed and stored
properly. We're working on
methods to extract and concen-
trate phytase and xanthophyll at
lower cost and with a less
energy consumption," says
Koegel.
The alfalfa juice also pro-
vides new sources of human
dietary protein. Koegel and
others previously designed an
extraction system that is now
used by several villages in
northern Mexico to enhance the
largely grain-based, protein-
deficient diets there.-By
Linda Cooke McGraw, ARS.
Richard G. Koegel is at the
USDA-ARS Dairy Forage
Research Center, 1926 Linden
Dr. West, Madison, WI 53706; phone
(608) 264-5149, fax (608) 264-5147,
e-mail office@dfrc.wisc.edu *


Agricultural Research/April 1998













Two New Maples Resist Bugs, Cold
Breeders and nursery operators
looking for a better maple tree may
want to climb aboard the Red Rock-
et. Or, they can head for the New
World. Red Rocket has fiery-red
leaves and outstanding cold and
disease resistance. New World is an
orange-red maple tailor-made for city
landscaping. Red Rocket thrives in
USDA growing zone 3, where
temperatures can go as low as -400F.
Columnar shape and cold resistance
make Red Rocket an ideal line of
defense against wind and weather
around barns and livestock shelters.
It would also work well as a shelter
and screen around picnic areas and
industrial sites. New World can
thrive in zone 4, where temperatures
can drop to -300F. Unlike most
maples-and somewhat like an
American elm-New World sends its
branches up, then out. This shady
character, along with cold resistance,
makes it ideal for city streets and
residential neighborhoods in the
Northeast and Midwest. Nurseries
and breeders can request cuttings of
the new cultivars from the U.S.
National Plant Germplasm System.
Some wholesale nurseries may offer
the trees by 2000. Alden M.
Townsend, USDA-ARS U.S. National
Arboretum, Glenn Dale, Maryland;
phone (301) 344-4175, e-mail
nadt@ars-grin.gov/

Fungal Enzyme Could Help
Livestock Retain Phosphate
More of the enzyme called phytase
may be added to chicken and hog
feeds if new research leads to a more
economical approach. Without
phytase, poultry and swine excrete
lots of phosphate-a potential water
pollutant-in their manure. But
phytase is not a widely used feed
additive in the United States. That's


!4_ 0 -.Jpdate



mainly because the enzyme breaks
down under high temperatures during
the feed-production process. Recent-
ly, ARS scientists in New Orleans
identified an isolate of Aspergillus
fungi that makes phytase able to
withstand 1600F for several minutes.
The scientists are seeking a commer-
cial collaborator to help produce a
superior enzyme for use by the
animal feed industry. Edward Mul-
laney and Jaffor Ullah, USDA-ARS
Commodity Utilization Research
Unit, New Orleans, Louisiana; phone
(504) 286-4364, e-mail
emul@ nola.srrc. usda.gov
aullah @ nola. srrc. usda. gov/

New Kids' Diet Survey
Since December 1997, interview-
ers have been visiting households of
about 5,000 infants and young
children to gather voluntary data on
the foods they eat. This survey is an
extension of a larger 1994-96 survey,
What We Eat in America, that
covered all age groups. The new
survey covers only children under 10
years old. Information about this age
group from both surveys will help
those who are planning programs
dealing with children's needs, such as
food assistance and nutrition educa-
tion. But ARS is conducting the new
survey primarily to supply the
Environmental Protection Agency
with enough data for adequately
estimating children's exposure to
pesticide residues in the diet. The
estimates are required under the 1996
Food Quality Protection Act. Inter-
viewers under contract by ARS will
collect 2 days' worth of food intake
data in more than 60 areas around the
country. They will ask a parent or
other adult caregiver to provide the
information for children age 5 and
under. Six-to-9-year-olds will be
interviewed with their caregivers'
help. Sharon Mickle, USDA-ARS


Food Surveys Research Group,
Beltsville Human Nutrition Research
Center, Riverdale, Maryland; phone
(301) 734-5619, e-mail
smickle @ rbhnrc. usda.gov/

Navaho Blackberries May Firm Up
Domestic Berry Market
Fresh blackberries sometimes
appear only briefly in supermarket
produce sections because they
quickly turn soft and unsalable. Their
typical shelf life is only 3 or 4 days.
But one variety deserves to be better
known. ARS scientists recently
discovered that Navaho blackberries
have a shelf life of 14 to 21 days.
Navaho, the first thornless blackberry
with erect rather than spreading
canes, was bred and released by the
University of Arkansas at Fay-
etteville. But that was 10 years ago;
Navaho's staying power only recent-
ly came to light. In a test, ARS
scientists stored Navaho blackberries
in coolers like those the industry uses
before transporting the berries to
stores. Then they sent a test shipment
to The Netherlands. The test included
a 4-hour refrigerated trip for berries
from an Oklahoma farm to Dallas/
Fort Worth International Airport and
a 2-day air shipment with dry ice.
The berries arrived in The Nether-
lands firm, exceptionally sweet, and
consistently tasty-just as they were
when picked. The discovery should
give the fresh blackberry market a
boost. Navaho is adapted in the
Pacific Northwest, Southern Plains,
and South Atlantic regions. Penelope
Perkins-Veazie, USDA-ARS South
Central Agricultural Research
Laboratory, Lane, Oklahoma; phone
(405) 889-7395, e-mail
pperkins@ag.gov/


Agricultural Research/April 1998






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Agricultural Research/April 1998







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Beltsville Symposium XXIII: Food Quality and Safety


Salmonella, E. coli, Cyclospora--
are dreaded names of foodborne
pathogens associated with food
poisoning. But consumers can rest a
little easier knowing that USDA's
Agricultural Research Service is
gaining ground in the food safety war
against these and other formidable
enemies.
A major milestone in that war will
be the Beltsville Symposium XXIII
scheduled for May 3-6 at ARS'
Beltsville (Maryland) Agricultural
Research Center.
"Quality and safety of fresh fruits
and vegetables will be the focus of
this conference," says K. Darwin
Murrell, ARS deputy administrator.
"This theme is especially timely and
important because of the shifting
emphasis on marketing fresh
produce.
"New dietary research information
encourages us to eat more fresh
fruits and vegetables to maintain our
health," Murrell continues. "There-
fore, as agricultural scientists, we
need to ensure that fruits and vege-
tables contain the maximum nutrients
possible and that they are virtually
free of harmful microorganisms.
We're also looking for new methods
to produce, handle, and market both
fresh-cut and whole fruits and
vegetables."
Increased consumer demand for
fresh-cut fruits and vegetables for
convenience opens up a new food
safety issue. Cutting fresh produce
before marketing removes natural
barriers, exposing cut surfaces to


potential contaminants. ARS is
developing new intervention strat-
egies to ensure that pathogens do
not grow on these products.
Murrell says this symposium
marks the 23rd year that ARS has
hosted researchers, growers,
processors, and consumers to
discuss major issues that affect all
aspects of agriculture.
"The Beltsville Symposium
traditionally attracts an international
audience. Along with U.S. experts,
we also invite international, world-
renowned speakers to address
contemporary and currentissues,"
he explains.
Rolf Kuchenbuch of the Institute
for Vegetable and Ornamental
Crops in Grossbeeren, Germany,
will discuss sensory analysis of
quality, says Kenneth C. Gross.
Gross co-chairs this year's sympo-
sium with Chien Yi Wang, a horticul-
turist at the ARS Horticultural Crops
Quality Laboratory, which Gross
heads.
"Along with ARS scientists, we'll
also have speakers from New
Zealand; the Universities of Califor-
nia, Florida, Georgia, Hawaii,
Kentucky, and Massachusetts;
Michigan State University; as well
as from industry," says Gross.
Packaging and handling
microbial populations are primary
concerns for industry, as is HACCP
(Hazard Analysis Critical Control
Point) monitoring and controlling of
microbiological hazards. These
topics will be discussed by Robert


Brackett of the University of
Georgia; Dean Cliver of the Univer-
sity of California; and industry
representatives Devon Zagory of
Devon Zagory Associates, Davis,
California, and Tom Hankinson of
Pure Produce, Inc., Worcester,
Massachusetts.
This year's food safety and quality
theme is especially timely, since the
Food and Drug Administration plans
to issue its "Guide to Minimizing
Microbial Food Safety Hazards for
Fresh Fruits and Vegetables" in
June 1998.
Because of the importance of
quality as well as safety and shelf
life of both whole and fresh-cut fruits
and vegetables, a significant part of
the symposium will focus on mea-
suring and evaluating quality.
The symposium is co-sponsored
by Friends of Agricultural Research
at Beltsville (FAR-B). For additional
information or to register for Belts-
ville Symposium XXIII, contact
Kendra Jenkins, USDA, ARS, Bldg.
002, Room 117, 10300 Baltimore
Avenue, Beltsville, MD 20705-2350;
phone (301) 504-6128, fax (301)
504-5107.-By Doris Stanley, ARS.
Kenneth C. Gross and Chien Yi
Wang can be reached at the USDA-
ARS Horticultural Crops Quality
Laboratory, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-6128, fax (301) 504-5107,
e-mail kgross@asrr.arsusda.gov
cwang @asrr.arsusda.gov


ire




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