By Sharon Omahen


University of Georgia

A team of scientists has created a computer program that can
model an entire crop cycle, from planting to harvesting, in just
seconds.

The software is called Decision Support
System for Agrotechnology Transfer, or DSSAT. It was created
by a team of researchers from
the universities of Georgia, Florida, Hawaii, Guelph and Iowa
State and the International Center for Soil Fertility and
Agricultural Development.

Planting cyber fields

DSSAT allows the user to simulate a
crop’s growth, yield, water and nutrient requirements and the
environment’s impact on agricultural production.

The program wasn’t developed overnight. In fact, the software’s
fourth version was released earlier this year. About 50
researchers and graduate students from across the globe met on
the UGA campus in Griffin, Ga., May 17-26 to try out the latest
DSSAT software.

“This software program is by no means meant to be a substitute
for actual experimentation,” said Gerrit Hoogenboom, a DSSAT
developer and an agricultural engineer with the UGA College of
Agricultural and Environmental Sciences. “Experimental data is
still needed to establish credibility for models like DSSAT.”

Not a research replacement

Hoogenboom also said crop modeling software, like DSSAT,
is not a substitute for critical
thought.

“The results you obtain from the software are not ultimate
truths, and they’re not meant to replace real experiments, real
data or critical thinking,” he said. “Anytime you use a computer
model you should question the results.”

Though not a substitute for the real thing, the computer model
can have great value to researchers, educators, extension agents
and consultants.

“Computer models can provide an easy and very fast comparison of
many different crop management scenarios and the interaction with
local weather and soil conditions,” Hoogenboom said.

Sharing information with farmers

DSSAT simulates the growth of crops like peanuts,
sunflowers, sugarcane, wheat, soybeans, rice, tomatoes, sorghum,
millet, barley, potatoes, corn, blackeyed-peas and dry beans. The
next version of DSSAT will be of particular interest to
researchers in the southeastern U.S. as cotton will be added to
the simulated crop list. This version is expected to be released
in two years.

The crop-simulation information gained through the DSSAT software
will be shared with farmers.

“Our goal is to educate the people who talk to farmers directly,”
said Ken Boote, a DSSAT developer and University of Florida
agronomist. “Consultants, ag industry representatives and
extension agents have the potential to spread the word to
farmers. Those farmers with interest in this technology would
also benefit from actually using the software themselves.”

Boote says the way the software presents the data is an essential
part of the success of DSSAT.

“You can’t give numbers that no one can understand,” he said.
“Our program calculates crop growth and development in a
mathematical sense and then presents it through graphics.”

DSSAT has also been used as an effective tool after a crop has
been harvested to identify the source of production management
problems.

“It’s a way to see the whole picture and what is limiting the
crop,” Boote said. “The software actually works better this way.”

In the early stages, the software was tested
using several years of real-crop data from Florida and Georgia
farms.

Applications continue to grow

DSSAT has been used on food security projects in Africa and other
developing countries, too, and to study the impact climate change
has on food production.

“It’s been used in Arkansas to help with early-season soybean
plantings, in Kentucky for determining planting dates, in Georgia
for predicting agricultural water usage and in Africa to diagnose
yield loss of peanut crops from disease,” Boote said. “The list
of applications is never-ending.”

Two UGA agricultural economics students are using the program to
evaluate crop insurance. They hope to show the actual risks of
failure that farmers face. Two University of Florida students are
using the software to predict the amount of hay a farmer’s field
will produce when planted with bahia or bermuda grass.

There are currently more than 1,500 registered users from more
than 90 countries using the software.

“DSSAT users share their work and their data via a computer
listserver and a Web site,” Hoogenboom said. “In this way, the
software contributes to the whole scientific community.”