IIT Gandhinagar Study Maps Shift From Rice, Wheat to Maize and Millets

A new study led by researchers at the Indian Institute of Technology (IIT) Gandhinagar and Germany's Helmholtz Centre for Environmental Research (UFZ) suggests that shifting a targeted share of India's rice and wheat acreage to maize and traditional millets could cut groundwater extraction, nitrogen surplus and agricultural emissions, while maintaining calorie production and cereal-sector returns. The findings, published in Nature Communications, are based on cropping patterns across 664 districts in India.

The research team — led by Prof. Udit Bhatia and Dr. Shekhar Sharan Goyal of IIT Gandhinagar, with Dr. Rohini Kumar of UFZ — built an optimisation model, a computational method for finding the best land-allocation pattern. The model required that no state's calorie output fall below its 2017 level, that net returns from the cereal sector remain intact, and that any expansion of maize or millets be limited to areas with an existing history of growing those crops.

Under the proposed scenario, rice acreage could shrink by 8.8 per cent and wheat acreage by 12.1 per cent, with the freed land redirected mainly to maize and traditional millets such as jowar, bajra and ragi. This would raise the share of coarse cereals in India's total cereal cropland from roughly one-quarter to nearly one-third. The researchers describe this as growing crops where their environmental and economic costs are better matched to local conditions, not a wholesale replacement of rice or wheat.

The optimisation identified nitrogen surplus — fertiliser nitrogen that crops do not absorb — as one of the most important factors in improving the system's sustainability, and found that reducing it also produced water benefits, since groundwater stress, fertiliser use and crop concentration often overlap in the same regions. Paddy cultivation is associated with methane emissions and heavy water use.

The researchers say realising the proposed shift would require farmers to have access to reliable buyers, storage facilities, processing capacity and functioning value chains for maize and millets.