Optical Sensor Could Revolutionize Application of Granular Fertilizer
Tony Grift; 217-333-2854; firstname.lastname@example.org,
Writer: Leanne Lucas; 217 244-9085, email@example.com
A new optical sensor that "predicts" the spread pattern
of granular fertilizer could dramatically change the way farmers
calibrate spreaders and apply granular fertilizer. Traditional
calibration is a cumbersome process and dependent on the weather
constraints of wind and rain, said Tony Grift, University of Illinois
agricultural engineer. It involves driving a spreader over a row
of 25 collection trays to collect the fertilizer and weighing
each tray’s contents to determine the spread pattern.
By contrast, the optical sensor, installed on a spinner-type
spreader, automates this process. It can predict a spread pattern
by measuring the velocity and diameter of fertilizer particles
as they pass the sensor. To compute velocity, the particles interrupt
a double light beam, and the time between the two interruptions
is measured. The amount of time a particle blocks either light
beam is also measured and combined with velocity to determine
This information is then used in a mathematical model that predicts
where the granules will end up on the ground. Accumulation of
a large number of landing spots reveals the shape of the spread
pattern. A custom computer program uses this pattern to calculate
a simulated pattern for a preset swath width.
Grift and a colleague, Jan Willem Hofstee, began development
of the sensor in 1993. Hofstee is an agricultural engineer at
Wageningen University in the Netherlands and is currently on sabbatical
at the U of I. Grift believes the optical sensor provides the
technology necessary for the needs of high-tech farming, also
known as precision agriculture. "In precision agriculture,"
Grift said, "we need to be able to vary the application rate
of fertilizer depending on the demands of the crop and soil.
"The spread pattern on a traditional spinner-type spreader
is usually very bad, with peaks and valleys," Grift continued.
"Peaks mean you are over-applying and there is an economical
loss. Valleys mean you are under-applying, and the crop is not
going to grow very well." This is the pattern that emerges
when the spreader is used at a constant rate. "If you start
varying the rate," said Grift, "the pattern gets even
worse. So we had to come up with a method that would not only
automate the calibration but also allow us to change the application
rate in real time."
In his research, Grift uses a single disk, spinner-type spreader,
which has a round hopper with two feed holes. He and a grad student
are currently working on a design that places three "fingers"
within the two feed holes. "When we vary those fingers, we
can put the fertilizer wherever we want to," said Grift,
"and we can produce a very good spread pattern with a very
poorly designed spreader.
"Professional applicators will be able to use this kind
of system," Grift noted. "The tractor operator will
have a computer screen he watches. He makes one sweep to get an
indication of his spread pattern. Then he determines the swath
width he needs to get his application rate. When a different application
rate is needed, the process is repeated. He has a calibration
system that he can take with him on the fly, all the time."
In his current study, Grift uses the sensor to measure particles
that pass through the sensor individually. But clusters of particles
also pass through the sensor. Grift has taken the development
of the optical sensor to the next level, measuring these clusters
to determine mass flow. Mass flow is computed by measuring the
lengths of the clusters to statistically estimate the number of
particles per cluster. "It's a natural progression,"
said Grift, "going from single particles to mass flow. The
concept can be used in higher density mass flows such as the aerial
application of fertilizer. In fact, the concept can be used in
many industries where mass flow is important. In the end, this
might be more important than the original application."
For more information on the optical sensor, log on to the Agricultural
and Biological Engineering website at www.age.uiuc.edu. From there,
click on the Faculty and Staff button to find Grift's homepage.
On the homepage, go from Research Areas to Biosystems Automation
to Precision Agriculture to Smart Fertilizer Spreader System.
Establishing Buffer Zone for Genetically Modified Crops
Dell Rae Moellenberg, 970-491-6009, firstname.lastname@example.org,
Colorado State University News
A Colorado State University study takes a step towards finding
solutions to pollen drift from genetically modified plants onto
organic and traditionally grown crops, a concern raised by some
members of the public. The study shows that in Colorado, about
150 feet may be a reasonable buffer zone between genetically modified
corn plots and organic and traditional corn plots to prevent significant
cross-pollination due to pollen drifting from one field to another.
The first round study was conducted in Morgan County in eastern
Colorado, the state’s corn belt – and also a windy
area in the region, and at a second location on a plot in Boulder
County. Results showed that less than one1 percent of corn farther
than 150 feet from test plots is cross-pollinated by pollen from
the test corn. That means that very little of the pollen from
the test corn fields drifted more than 150 feet. “We realize
that one year’s data is not sufficient for this type of
study,” said Patrick Byrne, Colorado State University crop
sciences professor and researcher. “Given the year-to-year
variability in weather conditions, we will repeat the research
again during the 2003 growing season.”
The study tracked drift of blue kernel corn pollen at one site
in Boulder County and the drift of Roundup Ready corn, a genetically
modified crop, at the Morgan County site. The corn was planted
adjacent to corn varieties without those traits. When the corn
was harvested, samples were collected from various distances away
from the test plots. These samples were tested for traits from
the test plots, which indicate the amount of cross-pollination.
The farthest sample was collected 305 meters – about 915
feet -- away from the edge of the test plots.
Cross-pollination was highest at the closest sampling sites --
up to 46 percent at three-quarters of a meter south of the blue
corn plot in Boulder County. However, cross-pollination dropped
off in a short distance, with only 0.5 percent cross-pollinated
kernels near the blue corn plot at 150 feet. At that same distance
in the Morgan County plot, 0.75 percent of the corn showed cross-pollination
with the Roundup Ready test plot. The farthest distance at which
any cross-pollination was detected was 600 feet in Boulder County
and 270 feet in Morgan County.
“The growth in U.S. acreage planted with genetically modified
crops has been paralleled by growth in the demand for organically
produced foods,” said Byrne. “It can be argued that
both genetically modified and organic agriculture are approaches
to improving conventional farming methods, but the two forms of
agriculture are in conflict because of U.S. organic standards
that prohibit the use of genetically modified products and pollen
drift from genetically modified crops to nearby organic fields.
Given the growing importance of both the biotechnology and organic
sectors of food production, co-existence between the two becomes
a critical issue. We hope that this study will eventually help
to establish protocols for co-existence of these two types of
This study came out of discussions in Boulder County, where Byrne
served on a committee to study the concerns of that county’s
residents, particularly those who raise organic crops, with allowing
the farming of genetically modified crops on county-owned open
space land. The study was used to establish genetically modified
crop protocols on county open space cropland.
Similar Swine Diets May Actually Be Different
David Elstein, 301-504-1654, email@example.com,
ARS News Service, USDA
Swine that are fed the same diet in different locations don't
always get the same level of nutrients. That's the conclusion
of Agricultural Research Service scientists who participated in
a collaborative study, with 24 universities from north-central
and southern regions of the United States, to evaluate the consistency
of feed mixtures fed to swine.
The ARS Roman L. Hruska U.S. Meat Animal Research Center in Clay
Center, Neb., along with university researchers, prepared the
same corn-soybean meal diet, fortified with vitamins and minerals,
at each location. Samples of each station's feed mixture were
later analyzed for crude protein, calcium, phosphorus and zinc
concentrations. Laboratory analysis showed that although the diets
were mixed uniformly, there was considerable variation in the
nutrient concentrations at the 25 test locations. In other words,
the diets mixed at some locations had higher levels of crude protein,
calcium, phosphorus and zinc than those mixed at others.
Part of the variation in crude protein came from the corn and/or
soybean meal that each location used. Differences in calcium and
phosphorus contents could have been caused by various sources
of supplemental dicalcium phosphate. Variation in zinc concentration
was probably due to erroneous amounts of trace mineral premix
added to the diet. Another reason for different results in calcium,
phosphorus and zinc concentrations may have been that some laboratories
do not routinely conduct mineral assays.
As a result of this study, published in the Journal of
Animal Science, scientists and technicians should be
careful when mixing test diets and should guard against drawing
incorrect conclusions regarding dietary treatment effects. Accuracy
in diet mixing is important when conducting animal nutrition research
at multiple locations.
Organic vs. Conventional Corn and Soybean Yields
Paul Porter, Univ. of Minnesota, firstname.lastname@example.org.,
published in the Agronomy Journal, March-April
A conventional two-year corn-soybean rotation that relies on synthetic
fertilizers and pesticides was compared with an extended four-year
certified organic rotation incorporating oats and alfalfa. Corn
and soybean yields slightly decreased in the organic system, according
to a 10-year study in Minnesota. When production costs (though
without taking organic price premiums into account) were calculated
the net returns of the organic compared to conventional systems
were equivalent. These results suggest that organic production
systems can be competitive with conventional production systems.