Assessment of impact of climate change on productivity of tea (Camellia sinensis L.) plantations in Sri Lanka

A study was undertaken to assess impact of climate change on productivity of tea lands in Sri Lanka. Findings of the study showed that tea cultivations at low and mid elevations are more vulnerable to adverse impacts of climate change than those at high elevations. The optimum temperature for tea cultivation was found to be about 22 °C. The study also indicated that reduction of monthly rainfall by 100 mm could reduce the productivity by 30 - 80 kg of 'made' tea ha"1. In different tea growing regions, the optimum rainfall for tea cultivation varied from 223 to 417 mm per month. Increase in ambient C02 concentration from the present ambient level (around 370 ppm) to 600 ppm, increased the tea yield by about 33-37 % depending on the elevation. Based on these estimated parameters, a simple crop model was developed for predicting tea yield under future climate scenarios. The model was incorporated into a special software package developed to assess impact of climate change on productivity of tea plantations. Yield projections by the crop model showed that rising temperatures and diminishing rainfall reduce tea yield in many tea growing regions except Wet zone Up country (WU). The results also predicted that tea yields are likely to increase at high elevations while the yields at low elevations are likely to reduce due to climate change. Hence, sustainable adaptation measures are proposed to minimize such adverse effects.