The EPIC crop growth and yield model (Williams et al., 1984; Doraiswamy et al., 2003) was selected to simulate the crop growth and development of winter wheat in Oklahoma. The EPIC model is a mechanistic model that describes the potential growth of crops as a function of solar irradiance, air temperature, precipitation, and crop characteristics. The model has evolved over the several decades into a widely use model and has gone through rigorous testing under various environmental conditions for crop yield simulation for crops that include winter wheat and spring wheat. In this project, the model-simulated LAI (leaf area index) was adjusted by the real-time LAI derived from MODIS imagery. A radiative transfer model was used to derive regional LAI throughout the crop season from the MODIS-250m reflectance data. Ground based LAI measurements were used to adjust the radative transfer model parameters for winter wheat crop. The model simulations was conducted at a spatial resolution of 1.6 km2 grid over the study area, and the final result was a winter wheat yield map.
Operational Crop Condition and Yield Mapping
Doraiswamy, P.C., J.L. Hatfield, T.J. Jackson, B. Akhmedov, J. Prueger, and A. Stern, 2004. Crop condition and yield simulations using Landsat and MODIS. Remote Sensing of Environment, 92:548-559.
Doraiswamy, P.C., S. Moulin, P.W. Cook, and A. Stern, 2003. Crop yield assessment from remote sensing. Photogrammetric Eng'g. & Remote Sensing, 69:665-674.
Williams, J.R., C.A. Jones, and P.T. Dyke, 1984. A modeling approach to determining the relationship between erosion and soil productivity. Transactions of the ASAE, 27:129-144.