WheatSim: A process-based wheat model linking organ development, plant architecture, and field-scale responses under environmental variability

Authors: WANG, ZHUANGJI - University Of Maryland; Timlin, Dennis; WU, XIAOCUI - University Of Illinois; EBRAHIMI, ELNAZ - Iowa State University; PENG, BIN - University Of Illinois Urbana-Champaign; PAFF, KIRSTEN - Los Alamos National Research Laboratory; Chang, Christine; Han, Eun Jin; Fultz, Lisa; SADEGHPUR, AMIR - Southern Illinois University; Ahn, Ezekiel; Fleisher, David; MITRA, ALAKANANDA - University Of Nebraska; BEEGUM, SAHILA - University Of Nebraska; Reddy, Vangimalla; HORTON, ROBERT - Iowa State University; TULLY, KATHERINE - University Of Maryland

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2026
Publication Date: 6/23/2026
Citation: Wang, Z., Timlin, D.J., Wu, X., Ebrahimi, E., Peng, B., Paff, K., Chang, C.Y., Han, E., Fultz, L.M., Sadeghpur, A., Ahn, E.J., Fleisher, D.H., Mitra, A., Beegum, S., Reddy, V., Horton, R., Tully, K. 2026. WheatSim: A process-based wheat model linking organ development, plant architecture, and field-scale responses under environmental variability. Computers and Electronics in Agriculture. 252. Article e112084. https://doi.org/10.1016/j.compag.2026.112084.
DOI: https://doi.org/10.1016/j.compag.2026.112084

Interpretive Summary: Wheat is a major crop in the U.S., and how well it grows depends on many environmental factors like weather, soil, and farming practices. To help farmers and researchers make better decisions, scientists use computer models to predict how wheat will grow and how much it will yield under different environmental conditions and management scenerios. WheatSim is a new and more detailed model that simulates how different parts of the wheat plant—like leaves and stems—develop and interact. This helps it more accurately represent the plant’s structure and how it produces grain. Another advancement in WheatSim is that it uses modern programming techniques to better capture how wheat responds to its environment and run efficiently on today’s high-performance computers. This model will be a powerful too for agricultural researchers, extension agents, and industry professionals to investigate the effects of management factors such as planting date, nitrogen and irrigation on wheat yields under a range of weather conditions and soils.

Technical Abstract: Simulating wheat (Triticum aestivum L.) growth requires both structural realism and predictive accuracy. Coherent estimations across three scales: organ-level morphology and physiology, plant-level structure and function, and field-level biomass production, are critical for representing wheat growth dynamics and interpreting environmental stresses. However, existing models are often imbalanced across these scales and lack high-fidelity botanical architecture. We present WheatSim, a process-based model that integrates the three scales with an improved representation of wheat botanical structure to enhance model robustness and generalizability. In WheatSim, a tiller hierarchy defines the plant structure. Organ-specific growth models are coordinated through this tiller structure, with GPU-based computation. Process-based soil and biochemical photosynthesis models are integrated for field conditions, carbon assimilation and transpiration. WheatSim achieved relative mean absolute errors of 0.1-0.3 (with exceptions) and elucidated organ-to-field stress responses in selected APSIM experiments. Consequently, WheatSim demonstrates a promising model design and provides a prototype for other cereal crops.