Guwahati: As climate change increasingly threatens Assam’s tea industry, scientists have found that the answer to protecting tea gardens may lie beneath the soil—in billions of microscopic organisms that quietly sustain the health of tea bushes.
A four-year study led by researchers from Nagaland University, in collaboration with the Tea Research Association (Tocklai), ICAR and several national and international institutions, has revealed how seasonal changes in temperature and rainfall dramatically influence soil microbes and enzyme activity in Assam’s tea plantations.
The findings, published in the peer-reviewed journal Environments, provide one of the most comprehensive assessments yet of how climate variability affects the biological health of tea soils in Northeast India.
The researchers studied soils from five representative tea estates in Jorhat between 2016 and 2019, examining seasonal changes in bacterial and fungal communities alongside key soil enzymes responsible for nutrient cycling.
Their findings show that climatic conditions directly influence microbial populations, which in turn determine soil fertility and the long-term productivity of tea gardens. The study also found a strong relationship between microbial abundance and enzyme activity, suggesting that these microscopic organisms can serve as reliable early-warning indicators of environmental stress.
Using advanced statistical tools, including Principal Component Analysis (PCA) and hierarchical cluster analysis, the team found that more than 80% of the variation in soil biological activity could be explained by just three principal climatic factors, highlighting the strong influence of seasonal weather on tea-growing ecosystems.
The researchers also successfully grouped tea estates according to their microbial and enzymatic characteristics, opening the possibility of developing location-specific soil management strategies.
“This study establishes soil microbial communities and enzyme activities as sensitive indicators of environmental change and sustainable tea production,” said Tanmoy Karak of Nagaland University’s School of Agricultural Sciences, who co-authored the study.
“We attempted to identify seasonal thresholds that favour beneficial microbial communities and understand how climatic variables regulate soil biological processes,” he said.
Nagaland University Vice-Chancellor Jagadish Kumar Patnaik said the findings could help shape climate-resilient tea cultivation practices across Northeast India.
“Such research is crucial for developing sustainable tea-growing systems and reinforces the university’s commitment to addressing regional environmental challenges,” he said.
Beyond identifying seasonal fluctuations in soil bacteria and fungi, the research offers practical benefits for tea growers. It could improve soil health monitoring through biological indicators, help optimise nutrient management and support sustainable cultivation practices at a time when erratic rainfall and rising temperatures are becoming major concerns for the tea industry.
The study is particularly significant because tea productivity and quality in Assam has increasingly come under pressure from climate change, while little information has been available on how these changing conditions affect the biological processes beneath the soil.
The multidisciplinary research team included scientists from Nagaland University, the Tea Research Association’s Tocklai Tea Research Institute, ICAR-Indian Agricultural Statistics Research Institute, Dibrugarh University, the University of California, San Francisco, the University of Kansas Medical Center, and other institutions.
The findings add to the growing body of evidence that protecting the invisible life beneath tea bushes could be as important as managing the crop above ground in securing the future of India’s tea industry.