- India is the world’s biggest user of groundwater for farming
- Depletion in groundwater may cause severe losses in crop production
- Increasing canal irrigation cannot compensate for groundwater depletion
By Papiya Bhattacharya
Groundwater depletion in India could result in a reduction in food crops by up to 20 per cent across the country and up to 68 per cent in regions projected to have low future groundwater availability in 2025, says a study.
Groundwater is a critical resource for food security, accounting for 60 per cent of irrigation supplies in India, the world’s largest consumer of underground water, said the study, published in Science Advances. But unsustainable consumption of groundwater for irrigation and home use is leading to its depletion.
Using high-resolution satellite imagery and census data, the study quantifies the impact of groundwater depletion on cropping intensity. As the second largest producer of wheat, rice and lentils in the world, India accounts for ten per cent of the world’s agricultural production with over 600 million farmers dependent on agriculture as a primary source of livelihood.
Any huge losses in production will not only affect Indian agriculture but will also threaten food security in South Asia and the world, the study says.
Meha Jain, lead author of the study and assistant professor at the University of Michigan, US, tells SciDev.Net: “Our results suggest that reductions in crop area will occur largely in the states that grow wheat, potentially leading to substantial reductions in wheat production in the future. This could have ramifications for food security given that India is the second largest producer of wheat globally — and wheat provides approximately 20 per cent of household calories in India.”
Sheshshayee Sreeman, professor at the University of Agricultural Sciences (UAS), Bangalore, says studies by other institutions have predicted similar results. “There is an increase in productivity but that unfortunately cannot match the rate at which resources are being depleted. Land resources are being depleted by urbanisation and industrialisation as are water resources.”
“There is an increase in productivity but that unfortunately cannot match the rate at which resources are being depleted”
- Sreeman, University of Agricultural Sciences (UAS)
The study considered whether irrigation canals that divert surface water from lakes and rivers can make up for groundwater depletion but found that this would favour farms close to canals, leading to unequal access.
“In our study we found that, compared to tube well irrigation (stainless steel pipe bored into an underground aquifer), canal irrigation was associated with less winter cropped area and cropped area that was more sensitive to rainfall variability,” says Jain. “This suggests that if farmers switched away from using tube wells to using canal irrigation, winter cropped area would likely decrease and become more sensitive to rainfall variability.”
Sreeman suggests increasing the “water productivity” of crops that are intense users of water, especially rice and sugarcane. “Scientists at the UAS are focusing on improving drought adaptive traits in rice,” he says. “Such research needs to be supported and expanded. This would be the best strategy to cope with food and nutrient demands in a scenario of depleting water resources.
“Multiple approaches are needed — increase in irrigation, improved access to surface water irrigation, increased groundwater recharge, adoption of water conservation strategies and switching to crops that are less water intensive. Our results show that only switching to surface water irrigation will not fully compensate for the loss of groundwater.”