Dip in annual rainfall may hit cardamom yield at ICH

A part of Indian Cardamom Hills, a region dependent on rain-fed cardamom agriculture.

A comprehensive study based on 60 years of data to assess climatic variability and its impact on the Indian Cardamom Hills (ICH) has revealed a concerning trend: a significant dip in annual rainfall.

While the dip in annual rainfall has been recorded as approximately 13.62 mm a year, the number of rainy days dropped by nearly 19.75 days over a 40-year period. In addition to reduced rainfall, the study also highlighted a noticeable increase in both minimum and average decadal temperatures. It shows that these rising temperatures pose a potential threat to cardamom yield and could impact water availability for irrigation. The study underscores the importance of adaptive agriculture and climate-resilient policies to safeguard cultivation and sustain cardamom production.

The ICH is the geographical terrain spread across Kerala and Tamil Nadu, covering over 2,000 square kilometres of mountainous region, mostly a 700–1,800 msl (mean sea level) high plateau spread between Kumuly hills (in the south) and Munnar hills (in the north). 

The research team included Sivajothi Ramalingam, Kazuaki Tanaka, Nainaru Tarakaramu, Muthusamy Murugan, Ashokkumar Kaliyaperumal, and M. Ijaz Khan. The study was published in Nature Scientific Reports, a peer-reviewed open access multidisciplinary science journal, recently.

For the study, long-term observed climate data as well as cardamom yield data were collected from the Cardamom Research Station, Kerala Agricultural University, Pampadumpara, Kerala, and subjected to statistical analyses. The study employed various statistical methods to analyse the variability and trends in climatic variables, focussing on surface air temperature and rainfall data in the Indian Cardamom Hills.

“The reduction in both rainfall and rainy days poses a threat to the local agroforest ecosystem, as extended droughts and long rainless periods coupled with sparse tree cover could negatively affect cardamom growth and yield,” says the study.

As the region’s dependence on rain-fed cardamom agriculture makes it highly vulnerable to climate change, irregular rainfall patterns pose a significant threat to livelihoods sustained by the ICH agroforestry system.

Rainforest climate

The Indian Cardamom Hills, until the past two and a half decades, enjoyed a typical rainforest climate. Consistent rainfall throughout the year provided optimal conditions for cardamom growth and yield, eliminating the risk of soil moisture deficits. The study was carried out after reports of significant yield loss following erratic pattern of precipitation during the past couple of decades.

The study recommends urgent action to implement sustainable agricultural practices, such as advanced irrigation techniques, diversified crops, and climate-resilient varieties, to maintain productivity in the face of the escalating climate crisis. It observes that tropical mountain ecosystems are at a tipping point, threatened by climate change and unsustainable practices.

The findings highlight the urgent need to protect cardamom forests and emphasise the importance of science-based planning and management for agriculture in regions like the ICH. “As global temperatures continue to rise, understanding and addressing the specific vulnerabilities of mountain ecosystems will be essential to safeguarding biodiversity and ensuring food security for the millions of people who rely on these regions,” says the study.