By Sharon Omahen
University of Georgia

It will never be as popular as Grand Theft Auto or The Sims. But among the world's agricultural scientists, increasing numbers are requesting the latest version of DSSAT software.

DSSAT is Decision Support System for Agrotechnology Transfer, a crop-modeling computer program. It was created by researchers from the universities of Georgia, Florida, Hawaii, Guelph and Mississippi State and the International Center for Soil Fertility and Agricultural Development.

International users

More than 1,500 registered users from 90 countries now use the software. The program lets them model an entire crop cycle, from planting to harvesting, in just seconds. It simulates a crop's growth, yield, water and nutrient requirements and the environment's impact on production.

About 50 international researchers and graduate students met on the UGA campus in Griffin, Ga., May 15-24 for a DSSAT software training session. The program's developers say it's popular, in part, because it lets scientists "grow" crops on their computer screens without breaking a sweat.

"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," said Gerrit Hoogenboom. A DSSAT developer, he's an agricultural engineer with the UGA College of Agricultural and Environmental Sciences.

A variety of crops

DSSAT software simulates the growth of crops like peanuts, sunflowers, sugarcane, wheat, soybeans, rice, tomatoes, sorghum, millet, barley, potatoes, corn, black-eyed peas and dry beans.

The latest version of DSSAT is particularly popular with researchers in the Southeastern United States, as it allows users to simulate cotton growth. Several participants in the recent training want to develop models for crops like sweet potato and sugarcane.

"This software program is by no means meant to be a substitute for actual experimentation," Hoogenboom said. "The software results are not ultimate truths. And they're not meant to replace real experiments, real data or critical thinking. They're more like hypotheses. Anytime you use a computer model you should question the results."

The software was created by and for agricultural scientists. But the developers say it can be easily used and understood by farmers and those with no science background. Several Web-based tools are being developed for many on-farm applications of DSSAT.

Easy to understand

"The way the software presents the data is an essential part of the success of DSSAT," said Ken Boote, a DSSAT developer and University of Florida agronomist. "You can't give numbers that no one can understand. Our program calculates crop growth and development in a mathematical sense and then presents it through graphics so users can easily understand the predictions."

Boote says the developers' goal is to educate all audiences.

"One of our goals is to educate the people who talk to farmers directly," Boote said. "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."

Besides simulating a crop cycle, DSSAT has been used to identify the source of production management problems after a crop has been harvested.

"It's a way to see the whole picture and what is limiting the crop," Boote said. "The software works nicely this way to determine whether water or nitrogen are limiting factors.

Uses keep growing

"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, in West Africa to diagnose yield loss of peanut crops from disease and in South Africa for predicting corn yields. The list of applications is never-ending."

To further extend the software's features, DSSAT users share their uses and results via a computer discussion list and Web site.

"In this way, the software contributes to the whole scientific community," Hoogenboom said.