23^rd Hybrid DSSAT Development Sprint at the University of Kentucky

The 23^rd DSSAT Development Sprint was held from August 4–8, 2025 at the University of Kentucky in Lexington, Kentucky, and continued the DSSAT tradition of collaborative innovation in agricultural systems modeling. Hosted by Dr. Montse Salmeron and the Department of Plant and Soil Sciences, the event brought together participants in-person and virtually, with representation spanning universities, research institutes, and agencies from across the globe.

This 23^rd DSSAT Dvelopment Sprint focused on advancing the DSSAT Cropping System Model and associated tools, fostering community and information exchange, and welcoming new developers to DSSAT protocols and workflows. The agenda was shaped by three main goals:

1. Improve DSSAT, the Cropping System Model and associated tools, application programs, and databases.
2. Provide a forum for communication and information exchange among developers, users, and others interested in modeling and decision support systems.
3. Entrain new developers in DSSAT protocols and methods.

Participants

In-Person

• Montse Salmeron, Benoit Vasseur, Simone Silvestri, Mounica Talasila (University of Kentucky)
• Fabio Oliveira, Thiago Berton Ferreira, Mariely Lopes dos Santos, Vakhtang Shelia, Willingthon Pavan, Gerrit Hoogenboom (University of Florida)
• Bruce Kimball (USDA-ARS, retired)
• Alwin Hopf (Idaho National Laboratory)
• Patricia Moreno (Colombia)
• Kwang Soo Kim, Shinwoo Hyun (Seoul National University, South Korea)
• Guillaume Ezui, Jacques Fils Pierre (International Fertilizer Development Center)

Virtual

• Kelly Thorp (USDA-ARS)
• Xu Tao (Kennesaw State University)
• Phil Alderman, Zeshan Mehmood (Oklahoma State University)
• Upendra Singh (International Fertilizer Development Center)
• Jose Guarin, Meijian Yang, Jyoti Singh (Columbia University)
• Jeff White, K.J. Boote, Cheryl Porter, Henrique Boriolo Dias, Cleverson de Freitas, Kapil Bhattarai, Virginia Covert, Rizwan Rafique, Alyce Monteiro, Vaasuki Marupaka (University of Florida)
• Jhonny Vasquez (Costa Rica)
• Santiago Cuadra (Embrapa, Brazil)
• Huan Liu (Aarhus University, Denmark)
• Jon Lizaso (Universidad Politecnica de Madrid, Spain)
• Valentina Stocca (Technical University Munich, Germany)
• Julia Boscariol Rasera (ESALQ-University of São Paulo, Brazil)
• Hüdaverdi Gurkan (Turkish State Meteorological Service, Türkiye)
• Attachai Jintrawet, Ratchaphum Jaikla (Chiang Mai University, Thailand)
• Emir Memic, Dennis Gekeler, Jonas Trenz (University of Hohenheim, Germany)
• Kritika Kothari, Shobhit Choubey, Rotash Kumar (Indian Institute of Technology Roorkee, India)

Presentations

This Sprint featured presentations highlighting recent research and development:

1. Benoit Vasseur: Intercropping with DSSAT-Mixed
2. Guillaume Ezui: Optimizing Nutrient Requirements in Space and Time for Increased Crop Yield and Income: The S2P Approach
3. Xu Tao: Farming Resources Optimization Using AI
4. Virginia Covert: Command-Line Interface for Ex-Post Analysis of N Application
5. Cheryl Porter: Update on the 2D Model
6. Bruce Kimball: Improvement in Soil Temperature Simulation – Accounting for Mulches
7. Kwang Soo Kim: Strategies to Overcome Initial Value Sensitivity in Local Optimization
8. Jeff White: ICASA Data Template & Data Dictionary
9. Alwin Hopf: Biofuel Carbon Intensity Modeling – DSSAT-GREET Linkage

Sprint Highlights & Working Topics

Model and Tool Advances

• XB2 and GB2 Tools: Upgrades for speed, reduced file size, new 2D input data support, and in-season yield forecasting.
• TREEGRO Model: Phenology improvements and positive feedback on biomass simulation.
• Soil Temperature: Enhanced routines now account for mulch effects, with datasets from six sites and five crops; ongoing development of STEMP.for with new thermal conductivity models and damping depth calculations.
• Intercropping: DSSAT-Mixed advances, model calibration, output improvements, and sensitivity analysis to plant population and root density.
• Salinity & Water Table: Refined modeling in CROPGRO and CERES; improved handling of user input and warnings.
• Calibration: Legacy (Aloha) and new soybean experiments incorporated; chickpea model refined for long-day effects.
• Nutrient Modeling: Expansion of P and K response in rice and maize; tomato N/P, greenbean P, CANEGRO N, and more.
• New Crop Models: Development initiated for finger millet, drawing on pearl millet model experience.
• ICASA Data Template & Dictionary: Enhanced templates, new documentation tools, and release via GitHub.
• 2D Soil and N Model Integration: New integration for richer water and N simulations.
• Visual Tools: Prototyping tools for better simulation summary visualization.

Software and Workflow Improvements

• Programming Environment: Updated DSSAT Shell and tools for latest Delphi IDE and libraries.
• Installer: New installer created and tested for smoother DSSAT deployment.
• CRAN Packages: Ongoing development and preparation of new R packages (csmparameter, csmsoil) for parameter management, soil data, and exposing Fortran functions in R.
• HiPerGator Cleanup: Streamlined data and storage for gridded simulations on HPC systems.
• DSSAT Portal: Server migration and updates to ensure security and future readiness.
• GitHub Management: Improved tag control and workflow automation for development.

Special Topics

• Grazing & Automow: Advanced development of new grazing modules and automated mowing functions.
• Waterlogging & Disease: Implementation of waterlogging in CERES Maize; expansion of disease modeling, including pest-vectored diseases.
• Irrigation Optimization: Evaluation of automatic and optimized irrigation routines.
• Radish, Grapevine, SOM Initialization: Ongoing adaptations and improvements for additional crops and soil organic matter dynamics.
• Pythia: Enhanced soil and weather data inputs, calibration tools, and workflow discussion for large-scale model calibration.

A Collaborative and Global Effort

As always, the hybrid format enabled lively in-person discussion in Lexington while providing seamless virtual collaboration across time zones and continents. Daily breakout groups, focused discussions, and plenary wrap-ups ensured that all voices contributed and outcomes were shared.

Looking Ahead

The DSSAT Development Sprint remains a cornerstone for the modeling community—delivering tangible progress in crop modeling, tool development, and global food system resilience. The 23^rd DSSAT Development Sprint strengthened international partnerships, accelerated technical advances, and set the stage for future innovation. The next DSSAT Development Sprint is scheduled for the first week in January, 2026.