Spring Wheat Yield Assessment Using Landsat TM Imagery And a Crop Simulation Model

) Monitoring crop condition and production estimates at the state and county level is of great interest to the U.S. Department of Agriculture. The National Agricultural Statistical Service (NASS) of the U.S. Department of Agriculture conducts field interviews with sampled fann operators and crop .. cuttings to obtain crop yield estimates at regional and state levels. NASS needs supplemental spatial data that provides timely infonnation on crop condition and potential yields. In this research. the crop model EPIC (Erosion Productivity Impact Calculator) was adapted for simulations at regional scales. Satellite remotely sensed data provides a real time assessment of the magnitude and variation of crop . condition parameters and this study investigates the use of these parameters as an input to a crop growth model. This investigation was conducted In the semi-arid region of North Dakota in the southeastern part of the state. The primaIy objective was to evaluate a method of integrating Landsat TM satellite data in a crop growth model to simulate spring wheat yields at the sub-county level. The input parameters derived ftom remotely sensed data provided spatial integrity, as well as a real-time calibration of model simulated parameters dwing the season to ensure that the mOdeledand observed conditions agree. A· radiative transfer model (SAIL) provided the link between the satellite data and crop model. The model parameters were simulated at the satellite pixel level in a geographic infonnation system, which was the pla1fonn for aggregating yield at local and regional scales. The simulation was run for each soil type within the county and the results integrated to provide county yields. The model simulated yields were similar to reported county averages and the farm level yields at selected NASS survey sites.