by Veronica Mae Escarez
A Nature report revealed that improving nitrogen use efficiency by lessening redundant nitrogen use and adopting sustainable agronomic practices such as proper water management and cropping calendars can help fight nitrogen pollution and climate change in South Asia.
As South Asia rises as the center of global rice production, it has become a hotspot for nitrogen (N) surplus because of its inefficient use. In rice farming, nitrogen is mainly present in the fertilizer and the soil. It is essential to plant health, influencing plant growth and crop yield. Overusing N fertilizers has been identified as one of the main drivers of climate change, air pollution, and biodiversity loss worldwide. Because of this, South Asian governments have been set back by about USD16 billion in 2023-2024 alone. However, merely reducing nitrogen fertilizer utilization without comprehensive follow-up plans may affect existing ecosystems reliant on higher nitrogen use.
Driving down N residues
New research led by Sam Coggins, a PhD student at the Australian National University, in collaboration with scientists and researchers from CGIAR, Indian Council of Agricultural Research (ICAR), and Cornell University, found that efficient nitrogen use and the adoption of sustainable agronomic practices can improve rice production and incomes and combat the impacts of climate change in South Asia.
“We provide a novel AI-driven spatial framework for targeting these that draws on the innovative Landscape Crop Assessment Survey (LCAS), spanning over 31,000 farmer fields across South Asia. “, shared IRRI Senior Scientist Anton Urfels. The areas included fields across Nepal, Bangladesh, and India.
Their data showed that nitrogen use efficiency (NUE) is the lowest in the Indian state of Bihar and some areas east of Uttar Pradesh with 32kg kg-1 due to low yields. NUE is the highest in Odisha state of India and Terai of Nepal at 60 and 52kg kg-1, respectively, because farmers applied less nitrogen and expected lower returns due to fertilizer use.
Specifically, the researchers pinpointed two ways of improving nitrogen use efficiency (NUE) in rice farming in South Asia.
The first solution called the N-saving pathway, pertains to curbing excess nitrogen use and is considered the most impactful alternative to improving NUE in the region. Estimations showed that an average rice field in the selected areas can produce the same yield when nitrogen use is decreased by 18kg ha-1. If all areas adopted the N-saving pathway, the region would have increased NUE by 22% by decreasing surplus nitrogen usage by 27%, lowering rice fertilizer subsidy cost by 17%. However, since N fertilizer is cheap in South Asia and is heavily subsidized by the government, farmers are not incentivized to go towards the N-saving pathway.
Driving up rice yields
The second solution, the yield-gain pathway, aims to increase crop yield without changing current application rates. The researchers have identified that improving water management and the cropping calendar can be the most impactful agronomic approach to achieving more efficient nitrogen use. Through this method, farms can reduce excess nitrogen use by 9% and improve overall rice production by at least 8%. This mitigation option matches the hypothesis that NUE increases as crop nitrogen requirement increases since the crops absorb most of the nitrogen.
Cruising in complementation
A key aspect of the research is that the N-saving and yield-gain pathways should be complementarily implemented. Landscape and management factors greatly vary depending on the area, so nuanced policies based on targeted and data-driven decisions must be delivered while recognizing smallholder farmers’ diverse needs and opinions on sustainable nitrogen management.
“By adjusting nitrogen application rates and agronomic practices, we can reduce nitrogen pollution by 36% while increasing rice yields by 8%. These findings highlight the power of data-driven, spatially targeted strategies to balance productivity with environmental sustainability.”, Urfels stated. “This is a tremendous win-win for food security, farmer incomes, and the planet. Our study shows how these novel datasets and AI-driven analytics have tremendous potential for improving rural livelihoods in harmony with nature.”
Reference
Coggins, S., McDonald, A.J., Silva, J.V. et al. Data-driven strategies to improve nitrogen use efficiency of rice farming in South Asia. Nat Sustain 8, 22–33 (2025). https://doi.org/10.1038/s41893-024-01496-3
