FIELD ESTIMATION FOR CORN AND WHEAT IN THE HUNGARIAN GREAT PLAIN USING SATELLITE REMOTE-SENSING DATA

Models to forecast crop yields using remotely sensed satellite data are intensively studied worldwide. After reviewing the experience gained by other researchers in this field, we selected procedures which might be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relationship between various remotely sensed spectral data (and their combinations) and the actually measured final yields we investigeted archived agricultural and Landsat MSS spectral data for 1984. A linear relation has been sought and found between the yield data for 47 corn and 55 wheat fields in Hajdu-Bihar county and various weighed and summed spectral quantities. Among the vegetation indices derived from satellite data and corrected for atmospheric effects the most promising were the spectral indicies sensitive to the green biomass. The latter, summed over a certain period in the growing season, exhibited a correlation coefficient of 66-93 percent, depending on the crop and the period of summation. Using the best models we performed regional yield estimation studies. Taking half of the crop fields used in the study we determined the yield estimation model and by its use we estimated the overall crop production for the other half of the fields. The error of the overall corn production estimated by this way turned to be less than 2 percent. The model developed for winter wheat proved to be sensitive to wheat variety.