1a. Objectives (from AD-416):
The first objective is to develop new modules to partition carbon, nitrogen, phosphorous, and potassium in individual leaves, modules for simulation of leaf growth and reproductive stages and organs in corn crop. The second objective is to develop algorithms to calculate the effects of nutrient and water stress on leaf addition rates. The third objective is to determine variety related parameters for the corn and potato models.
1b. Approach (from AD-416):
The corn model MAIZSIM and potato model SPUDSIM are under development. These models require additional modules and algorithms to improve in order to accurately simulate these crops under arid conditions of the northwestern United States. The collaborator using the data collected under irrigated conditions of the arid northwest will develop new modules and algorithms and integrate with the MAIZSIM and SPUDSIM models. These models will be validated against field data collected under a range of environmental, soil, and management conditions using several cultivars. They will also identify and develop cultivar specific parameters.
3. Progress Report:
In collaboration with ARS scientists at Beltsville, MD, researchers from the University of Washington have been improving the maize simulation model, MAIZSIM. They are working on MAIZSIM’s accuracy in predicting grain maturity, planting density effects on canopy development, carbon and nitrogen stress effects on leaf area and thickness, and leaf senescence. The maize model MAIZSIM has become one of the crop simulation models participating in a modeling inter comparison pilot study organized by AgMIP (Agricultural Model Inter comparison and Improvement Project) in 2012. As part of the AgMip activities, ARS scientists at Beltsville, MD and researchers from the University of Washington collaborated to produce maize yield simulations for multiple locations in Iowa, France, Brazil, and Tanzania sites under current and future climate conditions. In related activities, they also continued to participate in the Maize Model Improvement Expert Panel on-line meetings to represent MAIZSIM, and led a workshop entitled "Modeling maize leaf area expansion and senescence in response to CTW" at the Biological Systems Simulation Group (BSSG) Annual Conference at Penn State University. In April 2013 the University of Washington researchers visited with ARS scientists at Beltsville, MD to collaborate on maize model applications in climate change, regional food security, and other areas with modeling research needs. This same research group has now begun to develop methods for utilizing MAIZSIM and the potato model SPUDSIM along with the Geospatial Agricultural Management and Crop Assessment Framework (GAMCAF) tool that was adapted for the Pacific Northwest region. We are continuing our work to 1) improve MAIZSIM for modeling yield components during their reproductive stage, 2) enhance coupling of leaf expansion and carbon balance, and 3) testing model performance for a wide range of climate and soil conditions at diverse locations.