A new study from the Indian Institute of Technology Gandhinagar (IITGN) and the Helmholtz Centre for Environmental Research (UFZ) has shown that redesigning India’s cereal cultivation patterns around nitrogen management could significantly reduce environmental damage while maintaining calorie production and improving agricultural sustainability.
The work tackles the long-standing concept in sustainable agriculture of measuring the success of cropping mainly by the water saved. Contrary to this, the central insight of the article, published in Nature Communications , is that nitrogen surplus should be at the centre of that conversation instead. Nitrogen surplus is the portion of applied fertiliser that crops do not absorb. Unused nitrogen from fertilisers leaches into wells, washes into rivers, and evaporates into greenhouse gases such as nitrous oxide, polluting the atmosphere. It is also cheap to produce, which is part of why it is over-applied, and it lingers in the soil and wider biological cycle far longer than water does. That persistence and reach are strong reasons for why the planning focus should shift from water toward nitrogen, making the latter a strong policy target.
The collaborative work, conducted by Dr Shekhar Sharan Goyal and Prof Udit Bhatia from IITGN and Dr Rohini Kumar of UFZ, Leipzig, optimised the model to minimise nitrogen surplus. The authors noted that water use fell by 18.6% as a side effect, with savings of 86.8 billion cubic metres a year emerging as a near-automatic co-benefit. The reverse is not as effective. The water gain from a nitrogen-led approach is roughly 4.6 times larger than the nitrogen gain from chasing water. Translating the avoided damage into dollars, the nitrogen-led path averted about $1.19 billion (about ₹10,000 crore) annually.
“Indian agriculture pulls two emergency levers at the same time, too much fertiliser and too much groundwater. We have been trying to fix this one at a time,” said Professor Bhatia, corresponding author and an Associate Professor at IITGN’s Department of Civil Engineering . “What this analysis shows is that there is a single lever, nitrogen surplus, that meaningfully moves both. When we optimise for nitrogen surplus, water savings follow on their own.”
The reasoning is physical. Paddy rice, the crop the model contracts most, is simultaneously the most water-hungry, the most fertilised, and the largest methane source in Indian agriculture. Cutting rice area in over-stressed districts pulls all three pressures down together.
The team’s optimisation model reallocated existing cereal area across 664 districts among six grains — rice, wheat, maize, sorghum (jowar), pearl millet (bajra), and finger millet (ragi) — under strict rules: no state could fall below its 2017 calorie production, the cereal sector’s net returns had to hold at 2017 levels, and a crop could only expand where it had a documented cultivation history. In the recommended pattern, rice area contracts by 8.8% and wheat by 12.1%. The freed land is taken up by maize and three traditional millets (jowar, bajra and ragi) whose combined share of cereal cropland rises from about a quarter to nearly a third.
Crucially, the study does not call for replacing rice or wheat. It reallocates land at the margin, preserving existing cultivation and diets while making room for coarse cereals where they can grow well. This approach respects the “legacy” of what regions already grow and eat. The direction echoes the Government of India’s Shree Anna mission and the Sub-Mission on Nutri-Cereals under the National Food Security and Nutrition Mission.
The climate dividend is significant in the context of India’s 2070 net-zero commitment. The 8.7% reduction in agricultural greenhouse gas emissions includes both methane from rice paddies and nitrous oxide. With fertiliser pollution dropping by 13.4%, nitrogen leaching falling by 11.3%, and reactive nitrogen emissions by 13.9% nationally, the findings align with several United Nations Sustainable Development Goals , including Zero Hunger , Clean Water , and Climate Action .
“Pursuing food, water and clean air together requires a pivot point, and optimising for nitrogen surplus moves several goals at once,” noted Professor Bhatia, framing their findings as a way of navigating trade-offs between the aforementioned goals. “Reducing soil pollution also captures water savings, whereas optimising for water alone leaves soil pollution unaddressed,” he added.
The study also redraws how India’s interstate cereal trade network would adjust under the proposed restructuring. As rice and wheat shipments from major producing states decline, flows of maize, jowar, bajra, and ragi expand to keep importing states whole on calories. This includes new trade links between states that do not currently exchange coarse cereals. This could serve as a starting point for policymakers considering procurement, storage, and logistics for coarse cereals. The authors stress that this is a precondition, with the result resting on the assumption that markets are ready to procure these crops. Farmers shift toward whatever the market rewards. This is how rice displaced millets in several regions in the first place, driving fertiliser use sharply up. For a nitrogen-led restructuring to take hold, the policy has to actively build that market readiness through procurement, storage and logistics, and support prices for millets in areas where they are not currently offered.
That, Professor Bhatia cautions, means resisting blanket prescriptions. “The point is about growing the right crop in the right place, and pairing any push toward coarse cereals with the markets and support that let farmers make that choice without losing income.”
The authors are careful to note what the model does and does not do. It optimises cereal-to-cereal swaps only; pulses and legumes, which would further support nitrogen management, are a natural next step. The calorie constraint preserves food energy rather than full nutritional quality, though millets are richer in iron, calcium and several micronutrients than rice. Net returns are state-level benchmarks. In addition to farmers and procurement, real-world adoption also depends on consumers being willing to eat more coarse cereals, with Professor Bhatia optimistically remarking that millets have been gaining ground, particularly among younger and more health-conscious consumers.
According to Professor Kumar, the approach is not unique to India, with the European Union and China already weighing nitrogen-centric strategies. India’s climatological diversity and scale, however, give it room to redistribute crops without compromising food security. This is an option that many countries, with tighter markets and less varied growing conditions, do not have. Prof Kumar is a co-corresponding author and a computational hydrologist specialising in the water–land–climate nexus at UFZ.
Over the past few years, policymakers have intensified efforts to promote millets, while simultaneously grappling with falling groundwater tables in Punjab and Haryana, rising fertiliser subsidy burdens, and the challenge of decarbonising agriculture. The authors frame the finding as a case for balancing sustainability goals with feasibility rather than a blanket push toward any single crop. “Our study arrives at a moment when India is actively rethinking the future of its agricultural system,” said Dr Goyal, lead author and a research scientist at UFZ. “This is a modelling study, not an implementation plan. But it suggests that nitrogen surplus deserves a more central place in the way India thinks about sustainable agriculture,” he added.
Nature Communications
Quantifying environmental co-benefits of nitrogen-based crop restructuring and its implications on India’s interstate trade network
4-Aug-2026