Application of SPOT data to wheat yield estimation

The aim of this paper was to show the value of multitemporal short wave SPOT satellite data with high spatial resolution and high revisit capability to estimate wheat yield. The SPOT instrument programmation mode was fully used in order to get data at several important phenological stages along the wheat cycle. Two experiments (northern and southern France) in climatically and agronomically different contexts were conducted. Statistical relationships between final yield and multitemporal SPOT vegetation indices were tested. Adjusted yield values using a simple linear model based on SPOT data accounted for 50 %, 70 % and 80 % of the yield data variance. Quality of results quality was dependent on heterogeneity of physical and agronomical conditions. In the more homogeneous region which is mainly devoted to intensive farming, statistical relations between yields and multidate SPOT data were found to be significant on the whole fields data set in spite of the heterogeneity due to varietal factors and sowing dates. This study confirms that remote sensing using high resolution satellite can classify fields according to the yields on a regional basis and thus may be integrated in an yield forecast model.