Modelling and quantifying tea productivity in Northeast India

In India, the tea industry plays a leading role as a foreign exchange earner and a source oflivelihood to over a million people. Therefore maintaining the productivity and quality oftea is a national concern. Well-managed tea plantations can remain in production for up to 100 years. However, it has been observed that the peak production period occurs between 20 and 40 years. To gain a better understanding of some of the factors affecting tea agro-ecosystems in India and to suggest improvements, this study was carried out using data from several tea estates in Northeast India. By integrating G x Ex M factors, and yield simulation through CUPPA Tea model, the study tried to identify different factors affecting tea yield and its causes for decline. Such methods provide the means for the future monitoring of tea plantations. Further, the CUPPA tea model was parameterized to better represent G, E and M conditions in Northeast India. This allowed observed and predicted yields of mixed tea to match reasonably well, showing that it was worth further developing CUPPA Tea for the Indian situation. The model was most sensitive to photo period and changes in optimum temperature for shoot growth and extension. However, further calibrations and validations require a sharp genotype focus and future simulations should be done based on individual cultivars. The study further showed that strategic decisions should be given careful considerations at the estate, section and plant levels and that plantation managers should be given adequate knowledge to handle such
technologies efficiently to improve the productivity from their land and to optimize plantation input costs. Such issues would then go a long way to arrive at a complete revival of the tea sector in Northeast India.