A single lever could ease India's twin agricultural pressures of fertilizer pollution and groundwater stress

A study by the Indian Institute of Technology Gandhinagar and the Helmholtz Centre for Environmental Research suggests that reorganizing India's cereal cultivation based on nitrogen management could drastically cut environmental harm while preserving calorie output and boosting agricultural sustainability. The key finding, published in Nature Communications, is that nitrogen surplus, the part of fertilizer not absorbed by crops, should be the focal point rather than water savings.

Unused nitrogen contaminates water supplies, contributes to greenhouse gases, and persists in the soil longer than water. By minimizing nitrogen surplus, water use dropped by 18.6%, saving 86.8 billion cubic meters annually. The reverse is not true - water gains from a nitrogen-focused approach are roughly 4.6 times larger than nitrogen gains from focusing on water.

This strategy, which could avert about $1.19 billion annually, entails reallocating cereal acreage in 664 districts among six crops—rice, wheat, maize, sorghum, millet, and ragi—while keeping existing production levels and diets. The approach would cut rice land by 8.8% and wheat by 12.1%, expanding millet acreage to nearly a third of cereal cropland.

This conservation strategy aligns with India's net-zero goal and several United Nations Sustainable Development Goals, including Zero Hunger, Clean Water, and Climate Action.