Seasonal and interannual responses of the vegetation and production of crops in Cordoba - Argentina assessed by AVHRR derived vegetation indices

Advanced Very High Resolution Radiometer (AVHRR) -based vegetation indices are widely accepted as good indicators for providing vegetation properties and associated changes for large scale geographic regions. Also, their capability to indicate moisture conditions makes them an important data source for monitoring climate variations and droughts. The objective of this study was to test the AVHRR-vegetation conditions indices data set as indicators of the weather variability through the seasonal and interannual responses of the vegetation and the production of crops. Time-series of AVHRR vegetation condition indices during 1981-2003 were used to generate the seasonal and interannual vegetation curves for departments (administrative unites) of the Cordoba province in Argentina. Yield series of corn by departments were analyzed against AVHRR derived indices and corn yield predicting models were developed. Vegetation condition curves were able to differentiate vegetation responses associated with normal/above normal and below normal precipitation during the growing season. Corn yield models based on the vegetation condition indices explained up to 80% of the yield variation of corn, according to departments. Results from the analysis showed that the variability of the indices serves as good proxy for identifying environmental sources of variations mainly climate, and thus to provide insights for further analysis to understand the potential of the regional climate for crop production and the effects of the climate variability on vegetation and on corn yield.