has been the reigning experimental paradigm: Assume most variables
are constant, perform experiments on small plots, and extrapolate
results to a larger area without taking into account the myriad
environmental factors present on the farm.
This precision farming project instead tries to look at all
possible variables that could affect yield - to determine which are
most significant. They also measure how precision agriculture
affects the amounts of farming inputs needed - such as water,
nutrients, and pesticides - and whether the environment benefits from
this intensive management. The goal is to help farmers optimally
manage all parts of the field.
Cagatay Tanriverdi, CSU graduate student, monitors
soil water content with a timedomain reflectometry
Researchers at Colorado State University in Fort Collins and the
Colorado Agricultural Experiment Station manage the project with
Heermann. Additional State and federal government agencies and six
private companies also participate in the study.
Robert Geisick and Larry Rothe - commercial farmers near Wiggins,
Colorado - allow scientists to work on more than 300 acres of their
cropland for the study. They've seen variability in corn yields of
up to 50 bushels per acre across a single irrigated field. Both have
been keenly interested in precision farming, and Rothe was
independently trying to increase yields by using site-specific
He joined the project after meeting Heermann for lunch.
"We assumed fertility was our biggest problem, but we didn't know
for sure," Rothe says. "Here was someone who wanted to find out. It
didn't take me 10 seconds to agree."
Right now, both farms are growing corn under center-pivot
irrigation. Sugar beets or onions will enter the rotation in coming
The multidisciplinary team is looking at water distribution,
nitrogen management, nutrient availability, weeds, insects,
diseases, herbicide application, and a variety of soil
characteristics like organic matter and texture to assess their
relative impacts on yield.
The first 2 years of the study, which started in 1997, focused on
collecting baseline information based on the farmers' standard
methods of operation. But even preliminary results are already
Agricultural engineer Gerald Buchleiter collects
electromagnetic conductivity data to assess water and nitrogen
levels in soil.
Bauer "The scientists found that we're over applying
water - I hadn't even thought about monitoring our irrigation," says
Rothe. As a result of the finding, both farmers cut back
significantly on irrigation.
One of the handicaps of precision agriculture to date has been
the expense of collecting enough information across a field to apply
inputs on a site-specific basis. This study is evaluating several
methods that promise to reduce the cost.
For example, ARS agricultural engineer Walter C. Bausch uses
remote sensing rather than expensive lab analyses to assess where
there is adequate nitrogen. "The corn crop appears very healthy, in
part because more nitrogen is applied than the crop requires," says
Bausch. "That may result in nitrogen leaching."
Preliminary results from one area showed that nitrogen fertilizer
could be reduced by 35 pounds per acre without reducing grain yield.
Preliminary results also show that electrical conductivity of the
soil correlates well with yield, but scientists believe this is
really a surrogate measurement for other soil factors.