We’re working with our partners to explore how soil biology can help reduce the climate impacts of rice farming.
Healing the soil with fungi
We’ve been testing Alternate Wetting and Drying (AWD) with our farmers for the past three years, with promising results. We now know that, while AWD significantly reduces methane and water use, up to 10–15% of that benefit may be offset by increased nitrous oxide (N2O) emissions – another potent greenhouse gas.
This occurs when fields are no longer continuously flooded and the soil is increasingly exposed to oxygen, which encourages microbes to release N2O – especially in the presence of fertilisers applied to boost crop yields.
Since fertilisers are currently essential for maintaining yields and protecting farmer livelihoods, the challenge is to reduce N2O emissions without compromising productivity. That means using fertiliser more efficiently and more strategically.
Field data from the past three years of the Tilda Responsible Growing Programme shows that farmers involved in the programme achieved higher yields, while reducing fertiliser use. Farmers reduced fertiliser use by over 20% per tonne of rice on average across the three years 2023-25.
The knowledge we have gained is driving the next step in our climate journey: supporting pioneering research into ways to reduce nitrous oxide emissions in rice farming.
Healing the soil with fungi
Arbuscular mycorrhizal (AM) fungi help plants absorb nutrients more efficiently, acting as a natural bio fertiliser, meaning farmers could further reduce synthetic fertiliser use without compromising yields.
Research by the University of Cambridge Crop Science Centre (CUCSC) and the International Rice Research Institute shows that water-saving techniques like direct seeding can support the growth of this beneficial soil fungi.
Cambridge scientists believe AM fungi are likely to flourish under AWD irrigation systems, potentially reducing N2O and nutrient run-off, as well as improving soil quality – a suite of benefits that contribute to “healing the soil.”
We’re collaborating with research scientists to test bio-fertilisers that contain this fungi. The study aims to explore whether water-saving AWD techniques used on farms promote the growth of AM fungi. The project aims to compare data from AWD farms with farms using traditional continuous flooding methods.
The first stage of research, carried out in 2025 involved collecting and testing soil and root samples from 31 farms using microbiome sequencing. Samples were taken throughout the growing season and analysed for the presence of AM fungi. Initial microscope-based testing suggests that AM fungi are present in AWD soils but largely absent in continuously flooded fields. Full testing to confirm whether bio-fertilisers increase AM fungi levels on AWD farms will take place post-harvest.
Crop yields are also being recorded. Early comparisons with synthetic fertilisers have shown stronger root growth and improved plant performance, leading to hopes of yield gains at harvest time.
Looking ahead, we will carry out follow- up research to strengthen the evidence base and move the work closer to practical application at scale. Our aim is to generate robust, actionable data to support the wider adoption of bio-fertiliser use alongside AWD across commercial basmati farms, starting with the 2027 crop year.
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These early results are extremely encouraging. We’ve confirmed that AM fungi naturally associate with Pusa basmati rice, and that bio-fertilisers can enhance root development and crop vigor. Our next step is to quantify these benefits at scale and ensure that any inputs are truly sustainable.