Every farmer in the trial saw increased rice yield
In the rice fields of northern India, a soil-dwelling fungus is quietly rewriting the calculus of modern agriculture. Researchers from the University of Cambridge, working alongside thousands of basmati farmers and a UK rice company, have found that ancient symbiotic organisms — fungi that weave themselves into plant roots — can lift yields by up to 15 percent while easing the crop's dependence on synthetic fertilisers. At a moment when geopolitical instability and energy costs have made those fertilisers both expensive and precarious, this discovery sits at the intersection of ecological wisdom and practical necessity, suggesting that some of agriculture's most durable solutions may already be living in the soil.
- Synthetic fertiliser costs have surged due to global supply disruptions, leaving farmers in vulnerable regions with shrinking margins and few alternatives.
- Water-saving irrigation methods reduce methane emissions significantly, but inadvertently trigger nitrous oxide releases that partially cancel out those climate gains.
- Arbuscular mycorrhizal fungi — organisms that naturally colonise rice roots — showed yield increases of 5 to 15 percent across every single farm in the trial, without exception.
- The fungi appear to thrive in the drier soil conditions created by water-saving irrigation, potentially addressing the very nitrous oxide problem that sustainable farming introduced.
- The next phase of trials across nearly 4,000 farms will attempt to determine how much synthetic fertiliser can be reduced without compromising yields, turning a promising finding into a scalable solution.
In rice fields across northern India, researchers have uncovered something quietly powerful: a fungus that lives inside plant roots and helps them draw more from the soil. Led by the University of Cambridge in partnership with UK rice company Tilda and thousands of basmati farmers, the trials tested bio-fertilisers containing arbuscular mycorrhizal fungi — naturally occurring organisms that extend root reach and improve nutrient uptake. When applied alongside conventional synthetic fertilisers, yields rose between 5 and 15 percent on every treated farm in the study. Lead researcher Dr Emily Servante called the results extremely encouraging, noting that the fungi naturally associate with basmati rice and enhance both root development and overall crop vigour.
The trials unfolded on farms already using Alternate Wetting and Drying, a water-saving irrigation method that cuts methane emissions by roughly 45 percent by allowing fields to dry periodically rather than staying continuously flooded. The technique works well for the climate — but drier soil conditions trigger microbial activity that releases nitrous oxide, a potent greenhouse gas that can offset 10 to 15 percent of the methane savings. Mycorrhizal fungi happen to thrive in precisely these drier, more aerated soils, and early evidence suggests they may help suppress that nitrous oxide release, potentially closing the loop on a stubborn emissions trade-off.
The urgency behind this research extends beyond ecology. Synthetic fertiliser production is energy-intensive and deeply tied to natural gas markets, and recent years of geopolitical tension and supply chain disruption have driven costs sharply higher. For farmers already squeezed by input prices, the prospect of maintaining or boosting yields while reducing fertiliser dependency is as much an economic lifeline as an environmental one. Tilda's managing director framed it as both a sustainability priority and a food security imperative.
Tilda, which operates a sustainability programme across nearly 4,000 basmati farms and holds B Corp certification, will now scale the trials across that network to quantify how much synthetic fertiliser can realistically be reduced without sacrificing yields. What began as a laboratory observation about fungi and roots has grown into a test case for whether nature's own processes can help agriculture feed more people while asking less of the planet.
In rice fields across northern India, researchers have found something quietly powerful: a fungus that lives inside plant roots and helps them drink deeper from the soil. The discovery emerged from field trials led by the University of Cambridge in partnership with Tilda, a UK rice company, and basmati farmers scattered across the region. What they found matters because it points toward a way to grow more rice while using less of the synthetic fertilisers that have become both expensive and environmentally costly.
The trials tested bio-fertilisers containing arbuscular mycorrhizal fungi—naturally occurring organisms that form a symbiotic relationship with rice plants. These fungi extend the reach of roots into the soil, helping plants access nutrients more efficiently. When farmers applied these fungi-based products alongside their usual synthetic fertilisers, yields jumped between 5 and 15 percent compared to fields treated with synthetic fertilisers alone. Every single farmer in the trial saw this increase in their treated fields. Dr Emily Servante, the lead researcher at Cambridge's Crop Science Centre, described the results as extremely encouraging, noting that the fungi naturally associate with basmati rice and enhance both root development and overall crop vigour.
The timing of this discovery is not accidental. The trials took place on farms using a water-saving irrigation method called Alternate Wetting and Drying, developed by the International Rice Research Institute. Instead of keeping paddies continuously flooded—the traditional approach—farmers allow fields to dry periodically before re-flooding, using a simple soil tube to gauge when water is needed again. This practice cuts methane emissions by roughly 45 percent and reduces energy-related emissions by about 25 percent. But it creates a problem: the drier soil conditions trigger microbial processes that release nitrous oxide, a potent greenhouse gas that can offset 10 to 15 percent of the methane savings. The mycorrhizal fungi thrive precisely in these drier, more aerated soils, and Servante's work suggests they may help mitigate this nitrous oxide release.
The broader context makes this research urgent. Synthetic fertiliser production is energy-intensive and heavily dependent on natural gas. Recent years have brought geopolitical tensions, energy price volatility, and supply chain disruptions that have spiked fertiliser costs and reduced availability for farmers in many regions. For producers already squeezed by input costs, the prospect of maintaining or even boosting yields while reducing synthetic fertiliser dependency is not merely an environmental win—it is an economic lifeline. Jean-Philippe Laborde, Tilda's managing director, framed it as both a sustainability priority and a food security imperative, arguing that improving nutrient efficiency could help farmers reduce input dependency, lower costs, and build resilience against future shocks.
Tilda, the first UK rice company to achieve B Corp certification, now operates a sustainability programme across 3,840 basmati farms, delivering measurable reductions in water use and greenhouse gas emissions. The next phase of research will scale up the trials across this network to understand how much synthetic fertiliser can actually be reduced without sacrificing yields. Servante emphasized that the goal is to translate these early results into practical, sustainable solutions that work for farmers at scale. The work ahead involves quantifying the fertiliser reduction potential and ensuring that whatever emerges can be implemented reliably in the field. What began as a laboratory observation about fungi and roots has become a test case for whether nature's own processes can help agriculture meet the dual demands of feeding more people while using fewer resources.
Notable Quotes
Every farmer in the trial saw increased rice yield in fields where they applied mycorrhiza-based bio-fertilisers, compared to the fields without it.— Dr Emily Servante, University of Cambridge Crop Science Centre
By enhancing natural soil processes through bio-fertiliser use, our partnership could help farmers reduce input dependency, lower costs, and build resilience against future supply shocks.— Jean-Philippe Laborde, Tilda Managing Director
The Hearth Conversation Another angle on the story
Why does it matter that these fungi thrive specifically in drier soils?
Because the water-saving irrigation method that reduces methane actually creates a problem—it releases more nitrous oxide. The fungi seem to help manage that trade-off, which is why the timing of this discovery is so important.
So this isn't just about yield. It's about solving a problem that sustainable farming created.
Exactly. You can't just swap one practice for another and expect everything to improve. The fungi offer a way to have both the water savings and lower nitrous oxide, which makes the whole system work better.
What happens when they scale this up to 4,000 farms?
That's the real test. Lab results and small trials are one thing. Getting it to work consistently across thousands of farmers with different soil conditions, different management practices—that's where you learn if it's actually practical.
Is the yield increase enough to justify the cost of the bio-fertiliser?
The trials show 5 to 15 percent more rice. Whether that pays for itself depends on the cost of the bio-fertiliser and the price of rice, which varies. But even if the yield gain is modest, if you're also reducing synthetic fertiliser use, the economics start to shift.
And the fertiliser supply chain crisis makes this more urgent.
Right. When fertiliser prices spike and availability drops, farmers need alternatives. This isn't just a nice environmental story—it's about survival for farmers in vulnerable regions.
What's the biggest unknown at this point?
Whether you can actually reduce synthetic fertiliser significantly without losing yield. The trials used fungi alongside synthetic fertiliser. The real question is how much of the synthetic you can cut while the fungi make up the difference.