YIELD ESTIMATION FOR CORN AND WHEAT IN THE HUNGARIAN GREAT PLAIN USING LANDSAT MSS DATA

Models for the forecasting of crop yields using remotely-sensed satell ite data are studied intensively worldwide. After reviewing the experi ence gained by other researchers in this held, we selected procedures which might be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relations between various remotely-sen sed spectral data (and their combinations) and the actually measured f inal yields we investigated archived agricultural and Landsat MSS spec tral data for 1984. A linear relation has been sought and found betwee n the yield data for 47 corn and 55 wheat fields in Hajdu-Bihar county and various weighted and summed spectral quantities. Among the vegeta tion indices derived from satellite data and corrected for atmospheric effects the most promising were the spectral indices sensitive to the green biomass. The latter, summed over a certain period in the growin g season, exhibited a regression of 45-86 per cent, depending on the c rop and the period of summation. Using the best models we performed re gional yield estimation studies on 295 winter wheat and 218 corn field s. Taking half the crop fields used in the study we determined the yie ld estimation model and used this to estimate the overall crop product ion for the other half of the fields. The error of overall corn produc tion estimated by this way turn out to be less than 2 per cent. The mo del developed for winter wheat proved to be sensitive to the wheat var iety.