Iowa State University agronomist predicts the future through modeling

December 7, 2022

Sotirios Archontoulis. 

AMES, Iowa – Sotirios Archontoulis started out as a field crop researcher. “Every research project led to more questions,” he said. A mentor encouraged him to pursue modeling to find answers more quickly and cheaply. He took their advice and now he runs “What if” scenarios that help explain the present and predict the future.

“The computer environment allows easier exploration of many different factors,” said Archontoulis, Pioneer Hi-Bred Professor of Agronomy at Iowa State University. “Process-based modeling really boils down to identifying the optimum contributions of management and plant traits that can maximize productivity while minimizing environmental footprint.” 

He will discuss modeling projects he has led for the Iowa Nutrient Research Center (INRC) at the center’s upcoming water quality research seminar Wednesday, Dec. 14. Those projects have included assessing the impacts of weather and management on nitrogen loss and teasing out the impact of individual versus multiple nutrient reduction practices on water quality and farm economics.

Much of Archontoulis’ work has focused on the Agricultural Production Systems sIMulator (APSIM), a computer framework that contains more than 80 modules covering a range of plant, animal, soil, climate and management interactions. An advanced simulator of farming systems APSIM can analyze diverse combinations of management practices and/or cropping sequences to increase farm profitability and decrease environmental impacts.

Iowa State is the only member of the APSIM network in the United States, and Kendall Lamkey, chair of the Department of Agronomy, is a member of APSIM’s international seven-member steering committee. He calls agricultural systems simulation platforms like APSIM the “scientific equivalent of a theory of agronomy.”

APSIM’s set of models connect soil and plant processes (including nitrogen mineralization and plant photosynthesis), with factors such as weather and management (such as plant density and tile drainage) and attempts to represent the complex agronomic system.

“APSIM brings the biophysical areas of agricultural science together and provides a way of simulating production systems with the best available data and science,” Lamkey said.

Archontoulis has helped develop APSIM models and has used them to create several decision-support tools for Iowa farmers. Currently, he chairs the worldwide APSIM Reference Panel of about 20 researchers who assure the scientific quality behind the model.

Archontoulis also works on global climate models. He has been part of a team of international modelers responsible for the Agricultural Model Intercomparison and Improvement Project. AgMIP was center-stage this fall when Cynthia Rosenzweig, senior research scientist with the Goddard Institute for Space Studies, received the 2022 World Food Prize. She shared the credit with AgMIP developers, including Archontoulis, who have worked with her, praising their tireless work to further food security under changing worldwide climate conditions.

Chaoqun (Crystall) Lu.

“Models are great tools, but they’ve been used less in agriculture compared to climate science and other disciplines” Archontoulis said. “We still have a lot of work to do to convince stakeholders that our models are a viable, practical tool, but we’re making good progress.”

Learn more about modeling and its uses for water quality research at the upcoming INRC seminar series, Wednesday, Dec. 14, from 3:10-4 p.m. Archontoulis will be one of two presenters for this month’s session of the 2022-2023 “Highlights from a decade of research and impacts.”

December’s other presenter will be Chaoqun (Crystal) Lu, associate professor of ecology, evolution and organismal biology, Iowa State University, whose INRC projects have focused on ecosystem modeling and biogeochemistry. Watch this video to learn more about Lu’s work.

The monthly hybrid seminar sessions, which are free and open to the public, are held on the Iowa State campus in Elings Hall and online. Get more information or register to participate online at

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