Correlation analysis was carried out between area weighted averaged NDVI of tea for selected tea estate with their tea leaf yield for different years (2000-2004). The correlation coefficient ‘r’ values between yield and NDVI at critical time periods are shown in the table. Results showed that correlation is positive and significant irrespective of month of the NDVI over the years. During 2000 and 2001, tea leaf yield was found significantly related to NDVI at 95% level of significance while during 2003, correlation is positive at 1% level of significance.  *Significant at 0.05% level & **Significant at 0.01% level Variations could be well observed from Table 9. There were reasons for such variations. During the year 2000, there was outbreak of disease infestation due to heavy showers accompanied by high temperature and high humidity. This condition is highly favourable for Red Spider and Helopeltis attack. Apart from this, the ground LAI collected from the field showed lot of variations due to continuous plucking, infestations and also due to un-plucked areas. The different species also showed variations in the LAI readings. But still a significant correlation could be seen between tea leaf yield and MODIS NDVI of tea estates during different months. |