ON THE USE OF NDVI PROFILES AS A TOOL FOR AGRICULTURAL STATISTICS - THE CASE-STUDY OF WHEAT YIELD ESTIMATE AND FORECAST IN EMILIA-ROMAGNA

The use of satellite-derived vegetation indices for crop-monitoring and yield estimate and forecast is of key importance for those organizations in charge to monitor the agrarian season. This study intends to investigate the potential use of AVHRR/NDVI data for wheat monitoring in Italy. The time frame chosen is the 4-year span between 1986 and 1989, and the study region considered is Emilia Romagna. Two scales of study have been used: micro-scale and mesoscale. The first scale corresponds to the limits of NOAA satellite spatial resolution, and' has been used in the study of the vegetation index on restricted test sites, which, nevertheless, revealed a large number of data, including ground coverage. A wider scale has been considered to extend the results obtained in the microlevel analysis to the lowland section of the Emilia Romagna region. Good correlations were found with ground, simulated and collected crop parameters. In particular, NDVI has been found to be highly representative of plant photosynthetic capacity and efficiency. Using these results, a simple linear, regression model has been derived for wheat yield estimate and forecast based on NDVI integration during the wheat grain filling period. The results obtained, compared with official data, show their usefulness for a cheap and real-time crop monitoring.