Impact of age and management factors on tea yield and modelling the influence of leaf area index on yield variations

The study attempted to analyse the effects of age, pruning, and fertilizer application on tea yield and to derive a relation between yield and tea leaf area index (LAI). The study was motivated by the fact that tea yield has stagnated in Northeast India. To study the effects of age, pruning, and fertilizer application on tea yield, statistical analysis was applied to the data set collected at the section level of a tea estate from 1999–2007. Tea yield is correlated with age, NPK applications, pruning, and also leaf area index. Age showed a significant negative effect (R = 0.21–0.61). Clear negative effects of N application could be observed (R = 0.24–0.92). A significant positive effect of pruning could also be observed (R = 0.14–0.48). Further, an empirical equation was established between yield and measured LAI indicating that tea yield has a strong relationship with LAI (R = 0.62). The sectional averages also show a clear negative effect of N application and a clear positive effect of LAI over tea yield. Stepwise regression confirms that LAI could play an important role in predicting tea yield.