SORGHUM YIELD AND ASSOCIATED SATELLITE-DERIVED METEOROLOGICAL PARAMETERS IN SEMI-ARID BOTSWANA

Africa has sparse meteorological stations, hence it is increasingly common to use satellite-derived meteorological parameters, where in-situ measuremnts are not available. The objective of this study was to determine if there is a relationship between sorghum yield and meteorological parameters (measured and satellite-derived). Sorghum ( Sorghum bicolor ) yield for five seasons (2005/6 to 2009/10) from the Botswana Department of Crop Production Station in Pandamatenga, actual rainfall from the Botswana Meteorologial Services, and Normalised Difference Vegetation Index (NDVI) and Satellite Rainfall Estimates (RFEs) data from Famine Early Warning Systems Network (FEWSNET) were used in this study to determine relationships between the yield and satellite derived estimates. Although the NDVI and RFEs data were available for 2005 to 2011 (6 seasons), the limiting factor was the actual yield data which were only available for 2005 to 2010 (5 seasons). The Pearson Correlations Coefficient between seasonal rainfall and seasonal NDVI was 0.77 and seasonal RFE and seasonal NDVI was -0.19. Further correlation coefficient between sorghum yield and seasonal NDVI is 0.88. The correlation coefficient between sorghum yield and seasonal rainfall was 0.53; while correlation coefficient between sorghum yield and seasonal RFEs was -0.38. The sorghum NDVI signature reacted positively to the the seasonal rainfall, while sorghum NDVI signature was not correlated with the 1 Km resolution RFEs data. Furthermore, there was good correlation between sorghum yield and both the seasonal NDVI and seasonal rainfall, the seasonal NDVI seemed to predict yield slightly better than the seasonal rainfall. There seem to be a potential to use RFEs to predict yield though there are still problems associated with RFEs.L\u2019Afrique a des stations m\ue9t\ue9orologiques rares o\uf9 il est de plus en plus courant d\u2019utiliser des param\ue8tres provenant de satellites m\ue9t\ue9orologiques, o\uf9 in situ measuremnts ne sont pas disponibles. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer se il y avait une relation entre le rendement du sorgho et des param\ue8tres m\ue9t\ue9orologiques (mesur\ue9es et obtenues par satellite). Du sorgho ( Sorghum bicolor ) rendement pendant cinq saisons (2005/6-2009/10) du minist\ue8re du Botswana de la station de la production agricole \ue0 Pandamatenga, pr\ue9cipitations r\ue9elle de la Meteorologial services Botswana, et indice de v\ue9g\ue9tation normalis\ue9 (NDVI) et Satellite pr\ue9cipitations estimations (RFE) donn\ue9es de Famine Early Warning Systems Network (FEWSNET) ont \ue9t\ue9 utilis\ue9s dans cette \ue9tude pour d\ue9terminer les relations entre le rendement et le satellite estimations tir\ue9es. Bien que les donn\ue9es de NDVI et RFEs \ue9taient disponibles pour 2005-2011 (6 saisons), le facteur limitant \ue9tait les donn\ue9es de rendement r\ue9els qui ne \ue9tait disponible pour 2005-2010 (5 saisons). Les corr\ue9lations Pearson Coefficient entre les pr\ue9cipitations saisonni\ue8res et NDVI saisonni\ue8re \ue9tait de 0,77 et RFE saisonni\ue8re et saisonni\ue8re NDVI \ue9tait -0,19. En outre coefficient de corr\ue9lation entre le rendement du sorgho et NDVI saison est de 0,88. Enfin, le coefficient de corr\ue9lation entre le rendement de sorgho et pr\ue9cipitations saisonni\ue8re \ue9tait de 0,53; tandis que le coefficient de corr\ue9lation entre le rendement de sorgho et RFE saisonniers \ue9tait -0,38. La signature sorgho NDVI a r\ue9agi positivement \ue0 l\u2019pluies saisonni\ue8res, tandis que la signature sorgho NDVI ne est pas corr\ue9l\ue9e avec les 1 km de r\ue9solution RFEs donn\ue9es. En outre, il y avait une bonne corr\ue9lation entre le rendement de sorgho et \ue0 la fois le NDVI saison et des pr\ue9cipitations saisonni\ue8res, le NDVI saison semblait pr\ue9dire le rendement l\ue9g\ue8rement meilleur que les pluies saisonni\ue8res. Il semble y avoir un potentiel d\u2019utiliser RFE \ue0 pr\ue9dire le rendement se il ya encore des probl\ue8mes li\ue9s \ue0 RFE