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

Models to forecast crop yields using remotely sensed satellite data ar e intensively studied worldwide. After reviewing the experience gained by other researchers in this field, we selected procedures which migh t be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relationship between various remotely sensed spe ctral data (and their combinations) and the actually measured final yi elds we investigeted archived agricultural and Landsat MSS spectral da ta for 1984. A linear relation has been sought and found between the y ield data for 47 corn and 55 wheat fields in Hajdu-Bihar county and va rious weighed and summed spectral quantities. Among the vegetation ind ices 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 seaso n, exhibited a correlation coefficient of 66-93 percent, depending on the crop and the period of summation. Using the best models we perform ed regional yield estimation studies. Taking half of the crop fields u sed in the study we determined the yield estimation model and by its u se 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 whea t proved to be sensitive to wheat variety.