A study in India has shown that by increasing the price of water used for irrigation, farmers will use water more efficiently and plant crops that are more water-efficient.
The study was published in the July/August edition of the Agronomy Journal.
The research, by scientists from India's Punjab Agriculture University, and the United States-based Oklahoma State University and Texas A&M University, used a computer simulation to investigate the impact of using alternative crops on the amount of water farmers use.
Farmers in the Indian state of Punjab, traditionally wheat and rice growers, have long relied on groundwater to irrigate their crops. But evidence suggests that farmers overuse water because it is cheap. There is also evidence that the water table is declining, forcing farmers to use poorer quality water containing high levels of arsenic.
The scientists entered data known farming conditions in the Punjab region into the simulation model on, and modelled how different crops — maize, cotton, sorghum, soybeans and mustard — would respond to certain types of irrigation strategies. The model also assessed whether a higher water price would induce farmers to plant more water-efficient crops.
The computer simulation showed that if the state raised water prices to about 25 per cent of the price charged in large cities such as New Delhi, farmers would use less water, and use it more efficiently. Irrigation for a typical rice field could decrease by nearly 66 per cent.
Jeff Vitale, one of authors from Oklahoma State University, said the model showed that with higher water prices, it was likely that many producers would move away from rice to more water-efficient crops, such as cotton and soybean. It predicted that higher prices would have only a modest effect on farmers' incomes.
Vitale cautioned that as it was a simulation study, they would need to validate their findings with experimental data. The scientists are planning to test in the field to find out how crops perform under actual conditions.
But Devinder Sharma, from India's Forum for Biotechnology and Food Security, an independent collective of scientists, economists, farmers and policymakers, said the strategies suggested by the study should not be followed and that water wastage by farmers has been exaggerated. He said that although farmers in the Punjab are exploiting 98 per cent of the available groundwater, water wastage was more of a problem in urban areas like Delhi.
He said it is part of a move to vilify farmers, and force them out to make way for industry.
He added that the United States spends 85 per cent of its water on irrigation and so Western funded studies should not preach about water being lost in irrigation in India.
The study was funded by the United Nations Development Program.
Reference: Agronomy Journal 99, 1073 (2007)