Widespread reliance of rainfed crops on upwind irrigated agriculture in India

Akash Koppa, Francesca Bassani, Jessica Keune, Victoria Deman, Damian Insua-Costa, Vittal Hari, Subimal Ghosh, Diego G. Miralles, Sara Bonetti

Rainfed crops account for approximately 40% of India’s food production and support 60%
of its livestock. Although linked to oceanic monsoon rainfall, their productivity also
depends on terrestrial evaporation, particularly in the non-monsoon season. However, the
degree to which rainfed crops also rely on moisture sourced from upwind irrigated areas,
remains largely unknown. Using a combination of models and observations, we show that
upwind irrigated crops contribute 7%±6% of the rainfall over rainfed areas, rising to
15%±10% during the pre-monsoon months. In the absence of this input, water stress
experienced by rainfed crops can increase by 5–10% during the crucial mid to late crop
growth phases, potentially affecting yields. Our results reveal an unrecognized atmospheric
link between irrigated and rainfed agriculture, which is overlooked in current agricultural
policies. Planning and managing these systems in an holistic manner can help strengthen
regional food and water security under future climates.