So far in 2018, crop analysts have noted a strong disparity between satellite-based normalized difference vegetation index (NDVI) values for the United States (US) and crop conditions published in weekly USDA crop progress reports. Gro Intelligence is very interested in this difference because our successful US corn yield model generally relies more heavily on NDVI than crop conditions. Therefore the model remains price-bullish despite significantly price-bearish (good for yield) crop conditions.
Our research shows that over the ten states modeled by Gro in June 2018, crop percent good-excellent (Good+Exc) is a significantly better sole predictor of detrended final yield than NDVI taken alone. The most important words in that sentence are “taken alone.” Historically, a synthesis of all available data predicted yield the best, but if a single-variable approach must be used, the top indicator remains the crop progress report.