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 an d yield estimate and forecast is of key importance for those organizat ions in charge to monitor the agrarian season. This study intends to i nvestigate the potential use of AVHRR/NDVI data for wheat monitoring i n Italy. The time frame chosen is the 4-year span between 1986 and 198 9, and the study region considered is Emilia Romagna. Two scales of st udy have been used: micro-scale and mesoscale. The first scale corresp onds to the limits of NOAA satellite spatial resolution, and' has been used in the study of the vegetation index on restricted test sites, w hich, nevertheless, revealed a large number of data, including ground coverage. A wider scale has been considered to extend the results obta ined in the microlevel analysis to the lowland section of the Emilia R omagna region. Good correlations were found with ground, simulated and collected crop parameters. In particular, NDVI has been found to be h ighly representative of plant photosynthetic capacity and efficiency. Using these results, a simple linear, regression model has been derive d for wheat yield estimate and forecast based on NDVI integration duri ng the wheat grain filling period. The results obtained, compared with official data, show their usefulness for a cheap and real-time crop m onitoring.