India: Research shows plastic-lined farm ponds for horticulture worsen regional water scarcity

On a local level, plastic-lined farm ponds are a welcome income-booster for farmers in India’s semi-arid regions. These ponds store groundwater that make it possible for farmers to irrigate all year round, including water-scarce periods, and to grow high-value orchard crops such as pomegranates and grapes. But research shows that their regional effects can be paradoxical: an over-reliance on the ponds leads to unsustainable groundwater use, and the resulting water scarcity harms other farmers and residents who depend on shallow public drinking water wells.

In a new open-access paper recently published in the journal Agricultural Water Management, IHE Delft researcher Pooja Prasad and co-authors argue policy should discourage infrastructure-driven adaptation such as plastic-lined farm ponds, which lock farmers into cultivating crops that require a fixed amount of year-round irrigation, in a highly uncertain environment. Instead, they argue, seasonal intensification in which farmers retain their ability to adapt their cropping intensity to changes in availability of water should be encouraged.

Using modelling and systems analysis based on extensive interviews with farmers, the researchers argue that promotion of plastic-lined farm ponds triggers a cycle of increasing agricultural intensification that goes beyond what can be supported by available groundwater. “In absence of collective action and community control,” this could lead to “increased inequity in access to groundwater, fall in agricultural productivity” and a situation in which everyone is worse off, the paper states.

But the plastic-lined ponds already are a driver of inequality, the researchers argue.

“Our model shows that in drought years, the use of ponds significantly reduces the availability of water resources. This increases the inequality between those who have access to irrigation water through the ponds, and those whose access to water is precarious,” Prasad said.

The paper calls for trans-disciplinary participatory action research to support farmers to monitor water availability, prepare seasonal water budgets and adapt their cropping intensity accordingly.

“There is also a need to co-produce policy inputs for government programs that currently promote farm-ponds and horticulture” without considering how they affect groundwater availability, the paper states. The Indian government provides subsidies for plastic-lined farm ponds for orchard cultivation, and for the energy used to pump groundwater into the ponds when water is available, and from the ponds to irrigate orchards during the dry summer.

p.prasad@un-ihe.org