Combating Adverse Impacts of Climate Change on Tea Production in Sri Lanka with “No-Regret Strategies”

By  M.A Wijeratne

Senior Research Officer & Officer-in-Charge - Tea Research Institute, Low Country Station, Ratnapura

The human impact on the environment associated with economic growth and development is believed to be a primary cause of global warming.  Such warming has profound impact on living beings and plant life. For instance, photosynthesis, the process by which plants produce organic compounds is largely governed by ambient temperature, carbon dioxide concentration and soil moisture (rainfall). Changes to these environmental factors can  incur profound impact on photosynthesis and in turn, affect crop growth and yield.

Temperature rise, enrichment of ambient carbon dioxide (CO2 ) and  variation of total and pattern of rainfall distribution change crop environments, thus affecting crop growth and yield of non-irrigated plantation crops such as tea. Pest behaviour and disease infestations which are impacted by environmental changes are also closely linked to the productivity of tea land.  Moreover, changing environment can adversely affect product quality. In the recent past, scientists have begun to explore  climate change and assess its impact on crop growth and yield. Fortunately, such studies have paved the way for scientists to identify appropriate measures in which adverse impacts of climate change on agricultural crops such as tea can be mitigated.

Climate Change Impacts on Tea Production 

Tea is Sri Lanka’s topmost agricultural export. It is one of the major plantation crops grown from nearly sea level to around 2200m amsl. The total tea land is estimated to be 200,000 ha of which approximately 60% is managed by smallholders contributing to about 70% of the national production. In 2010, Sri Lanka produced 329 million kg of tea earning an estimated Rs. 155,376 million (Central Bank of Sri Lanka, 2010). The industry is said to employ over 1.5 million people..

Close analysis of climate change impacts on tea production in Sri Lanka shows that tea cultivations at high elevations (>1200 m amsl) are least affected. Rising temperatures are beneficial to tea grown at high elevations as it helps to reach optimum temperature for tea (22 oC). However, it is predicted that rising temperatures and dry weather conditions in warmer regions where the present temperatures are above optimum for tea (low; <600m amsl and mid; 600-1200m amsl elevations) will mask the benefits of CO2 enrichment and limit tea production. In addition,  poor soil conditions and ageing tea bushes make tea lands highly vulnerable to the adverse impacts of climate change.  In order to mitigate such adverse impacts on tea lands in Sri Lanka, it is crucial to adopt good agricultural practices that are also known to be “ no regret strategies”.

Adapting Measures 

Proposed adaptation measures seek to minimize  adverse impacts of extreme (high) temperatures and moisture stress and, ensure that the beneficial effects of CO2 enrichment is properly exploited for sustaining tea yield. They are primarily aimed at improving soil conditions, aerial environment, and adaptability of the crop to stress conditions.

Challenges 

The adoption and long-term implementation of “no-regret strategies” detailed above hinges on two factors; firstly, the profitability of tea cultivation which in turn, limits the capacity of the tea grower (affordability) to effectively adopt such strategies in the field, and secondly, the availability of labour and other resources and required materials  which will facilitate such good agricultural practices that have so far  not been fully adopted in tea lands . It is contended that financial assistance to tea growers will markedly improve the rate of adoption of such “no-regret strategies” whilst minimizing the adverse impacts of climate change.

M.A.Wijeratne

M.A.Wijeratne is a Senior Research Officer and the Officer-in-Charge of the Tea Research Institute - Low Country Station, Ratnapura. He has published extensively in both local and international journals and books in the areas of tea agronomy and physiology, mechanization of field practices, climate change and land degradation. He was awarded the General Research Committee (GRC) Award of the Sri Lanka Association for the Advancement of Science (SLAAS), and the Science and Technology Award for his outstanding contribution to research in Sri Lanka. He is a member of the Faculty Board of Agriculture, University of Ruhuna and a visiting lecturer of the University of Ruhuna and Uva Wellassa University, Passara.

M.A.Wijeratne is an inventor and has received patent rights for inventing a selective tea harvester, collapsible tea plucking basket, hand pruner and deep fertilizer applicator. He has received two Presidential Awards in Sri Lanka and two Gold Medals from Geneva, Switzerland for his inventions. He has been appointed as an Assistant Commissioner to the Sri Lanka Inventors Commission.

He obtained his BSc in Agriculture from the University of Ruhuna in 1987 and  his PhD in 1994 from the Wye College, University of London, U.K.