Grounds for hope: Coffee could make our soil, planet healthier, says Mridula Ramesh
Agricultural soils, under better management, could store up to 1.2 gigatonnes of carbon each year. That’s substantial – and coffee is showing the way.
Dappled sunlight filtered through the broad leaves of a jackfruit tree, before trickling through the waxy canopy of an avocado, casting a cool shade over my feet, which were sinking into the brown, mulchy soil as my fingers squeezed two creamy seeds out of a bright shiny cherry and onto my palm.
That was when it hit me: Origins matter: How you were shaped determines where you will thrive.
Here, in the Palani Hills, Coffea arabica was thriving in a cool, humid forested nook much like its ancient home in the Ethiopian highlands. Old and planted forests sheltered it from heat and wind, while the humus-rich soil supplied year-round moisture without drought or waterlogging.
Shaker Nagarajan, the owner of this plantation, tells me farms like his have been increasingly caught between elephants, labour-scarcity and storms, in recent years. He’s mindful of what trees he plants, because some, like the banana, draw the elephants that migrate seasonally to these slopes. “The calves really cause havoc,” he adds, running amok like toddlers do.
Coffee harvests fall between October and February, a season of festivals and rains in these parts, making labour expensive and hard to retain. A giant storm a few years ago knocked over a number of large trees (most of them non-natives with less-deep roots). That year, Nagarajan says, he was only able to salvage 25% of his crop.
Such storms may become more common as the planet warms.
As I mentioned in my last column, Part 1 of this two-part series on coffee, a 2015 study found that, based on current climate projections, about half the land currently used for coffee production would no longer be suitable for the crop, by the 2050s. Brazil, the world’s largest producer, will be especially hard-hit. Any gains at higher elevations will carry a steep deforestation cost.
For a world that consumes two billion cups of coffee a day, this is terrible news. But there is a way forward. I even saw it in action here: forests and soil, working together.
In the early afternoon, it was cool at the plantation and a light drizzle fell. “I used to maintain 40 trees to provide shade to the 1,200 coffee plants on every acre of land,” Nagarajan said. “Now, with temperatures rising, I have increased the number of shade-providing trees to 100 per acre.”
David Hogg, chief agriculture advisor at Naandi Foundation, which supports Araku Coffee, the makers of award-winning coffee produced in collaboration with over 10,000 tribal families, agreed. “I measured surface ground temperatures both inside coffee farms and outside and consistently found the shaded coffee farms were 4 degrees Celsius to 7 degrees Celsius cooler,” Hogg said. “Forests were a natural buffer. So I was able to assure our trustees that Arabica coffee would remain resilient (here) for the next 50 to 100 years, provided the ecosystem was maintained.”
Rattan Lal, distinguished university professor of soil science at Ohio State University and a global authority on soils, told me, “When it’s about 27 degrees Celsius outside, the soil temperature may be 40 degrees Celsius, but under the forest canopy, it is only about 27 or 28 degrees Celsius. So, there’s a big difference.”
That’s temperature taken care of, for now. Forests also help intercept the heavy downpour, and maintain humidity in dry months.
The other adaptation is soil.
Plants, like us, need water to maintain structure, move nutrients around, fuel photosynthesis and cool themselves. Most plants draw almost all their water through their roots from the soil. So, when water content in soil falls, yields suffer.
Soil is a dynamic matrix of mineral particles, organic matter, water, air and microorganisms. Healthy soil strikes a Goldilocks balance: enough large pores to let rainwater soak in and, during heavy downpours, drain away; and enough medium pores to hold onto water against gravity, yet release it when plants need it. Humus (the organic-litter component of soil) helps keep this pore ratio just right. It also acts as a sponge. Soils rich in organic matter can store far more water — anywhere from roughly one part water per part humus to eight parts water per part humus.
Organic matter reengineers the soil’s plumbing. Vitally, it also contains microbiota that can break organic matter down into a form of nitrogen that can be absorbed by plants.
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In India, we have destroyed our soil.
Lal tells me tropical soils should ideally contain 1% to 1.5% organic carbon, but in many Indian farms, especially in the northwest, it is now 0.1% to 0.2%, because “we take away the crop residue and either burn it or convert it into feed where the dung doesn’t return. So, Indian soils are really depleted.”
That’s a problem. In 1937, in the aftermath of the Dust Bowl crisis, US President Franklin D Roosevelt wrote: “The dust storms and floods of the last few years have underscored the importance [of programmes to] control soil erosion... The Nation that destroys its soil destroys itself.”
Farmers try to compensate for falling soil health by adding more fertiliser or more water. “But that causes its own problem,” Lal says. “The efficiency of nitrogen fertiliser in India, under ideal conditions, is only about 30%. The remaining nitrogen, which is not absorbed, [leaches] into groundwater as nitrates, which harms the health of people who drink it, or escapes into the atmosphere as nitrous oxide, a greenhouse gas 200 to 300 times stronger than carbon dioxide.”
Yikes.
The interesting thing, Hogg found, is that tribal farmers didn’t want to use chemical fertilisers. When they applied the urea the government gave them, they told him, “all the earthworms ran away”. This gave him the confidence to build an organic programme in the Araku Valley in Andhra Pradesh.
“Because coffee in Araku is surrounded by biomass, we integrated composting and microbial inoculants to restore soil health. Over the years, soil life returned, coffee quality improved, and Araku coffee began earning international recognition,” Hogg says. “Coffee thrives in a beautiful symbiosis with the forest, in which trees feed the soil with dissolved organic carbon. Organic carbon levels have doubled or tripled in five years, as soils once depleted by slash-and-burn practices began to regenerate. Levels rose from about 0.4% organic carbon to 1.6%, sometimes even higher. Some farms have even gone up to 6% organic carbon, so the sky is the limit.”
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Carbon here is not just about climate; it is also about soil health.
Soil carbon supports microbial life, modulates structure, improves aeration and, most importantly, holds water. This water-holding capacity reduces stress on coffee plants during dry periods, making them healthier and less vulnerable to disease.
“For me,” Hogg says, “this is the essence of regenerative agriculture: restoring soil life and protecting the environment for future generations.”
Interestingly, “as soil organic carbon levels rose, sweetness and flavour depth improved too,” says Hogg. Nagarajan echoes this.
For the longest time, Indian coffee growers didn’t have an incentive to focus on quality. They had to sell everything to the coffee board, and a small payment to the chief inspector ensured it would be certified as fair average quality, or FAQ.
With liberalisation, the focus on quality began.
And there’s more. The world is realising that coffee, blessed with a rich array of polyphenols, particularly chlorogenic acids, can be a health food. A seven-year study of 36,758 adults, published in the journal Current Developments in Nutrition in 2020, found that even modest daily coffee intake was linked to a lower risk of death. These polyphenols act as antioxidants, modulate the gut microbiome and slow glucose absorption in the intestine, reducing post-meal blood-sugar spikes.
What’s fascinating is this: researchers have found that shade-grown arabica in Thailand contained roughly twice the levels of chlorogenic acids and markedly greater antioxidant activity than beans grown in full sunlight.
There’s even more: Shade changes coffee’s carbon math. A new accounting method that recognises shade’s impact on soil and biomass carbon, and on erosion protection, developed by Lal and his colleagues, shows that shaded systems store significantly more carbon than unshaded plots. This serves to lower the carbon footprint of shade-grown coffee by 22%.
Lal told me he believes that soil, globally, could sequester about 2.5 gigatonnes of carbon each year (or nearly a quarter of what humanity emits annually). Agricultural soils, under better management, could store up to 1.2 gigatonnes of carbon each year. That’s substantial.
Climate resilience, less carbon pollution, health. Those are worthy goals. Araku’s experience shows that the methods can be scalable, fair (the company’s practices have raised farmer incomes) and aspirational. Araku has won the Epicure d’Or award for taste, and the Rockefeller Foundation’s Food System Vision Prize for sustainability.
To actually scale this across India, and around the world, needs more action. “India needs a Soil Health Act,” Lal says, “to incentivise farmers to grow carbon in their soils.” While there are new schemes to wean farmers away from fertiliser abuse, when one compares the ₹1.2 lakh crore budgeted in 2024-25 for urea subsidy to the ₹45 crore for the Policy on Promotion of Organic Fertilizers, one wonders how much the needle will shift.
But shift it must, for good coffee and so much more.
(Mridula Ramesh is a climate-tech investor and author of The Climate Solution and Watershed. She can be reached on tradeoffs@climaction.net. The views expressed are personal)
