State of the Planet

News from the Columbia Climate School


The Groundwater Crisis and the “Grass that Grows in the Water”

Recently, as I sat down for a meal with my family, my four-year-old son—who has been learning in school about where food comes from–asked us if we knew where rice grew. Not sure how to answer, I suggested that rice grew in many different countries.

“Rice comes from grass that grows in the water!” he said smiling.

He was right, of course—rice is a grass, and given the rapidly worsening freshwater crisis in the world’s must vulnerable places, the fact that rice is almost always cropped in large paddies of standing water may be the most important thing to know about it.

Workers transplant rice into standing water in Punjab, India.

Rice is the world’s third-largest crop after wheat and corn; by some estimates it accounts for fully one-fifth of the total calories consumed by the human race. Given these facts, it’s not surprising that countries that have historically struggled with devastating famine would do whatever it takes to ensure strong production of the grain, even if it meant promoting growing practices that would ultimately prove unsustainable.

Today the Columbia Water Center released a report highlighting just how severe the water-rice crisis has become in one of the world’s major water-crisis hotspots: the state of Punjab, in India.

Punjab accounts for a mere 1.6 percent of India’s land area, but it produces 12 percent of the nation’s foodgrain, through an all-but-universal practice of double-cropping each piece of land every year—a crop of wheat in the winter and crop of rice in the summer. Needless to say, the inputs – fertilizer, pesticides and most importantly, water—required to maintain this system are truly staggering. The role of rice in this system is particularly remarkable, given that almost no rice was grown in this semi-arid state prior to 1950.

After the famine of the 1960s, however, and with advent of Green Revolution techniques for more intensive cropping, successive governments began encouraging large-scale rice production through a suite of subsidies. These included minimum price supports and, most importantly, subsidized electricity to pump groundwater for irrigation.

As a result of these subsidies – in Punjab as well as other Indian states – India was able to all but eliminate the recurring famines that had devastated the nation for centuries. Doing so, however, did not come without a price.

Today, the study reports, on an annual basis the state of Punjab is overdrawing its groundwater supplies by a “clearly unsustainable” 45 percent. The rate of groundwater depletion averages about 4 tenths of a meter per year – but in some locations it is as high as 1 meter per year.

In order to chase this demon of depletion, farmers find themselves on an accelerating treadmill, forced to drill ever-deeper wells to flood their fields to grow the rice that their nation depends on. Meanwhile, the increasing amount of subsidized electricity this requires affects everything else – from grid reliability and service, to the state budget, which must divert money from other priorities such as health and education to support pumping.

The tensiometer

So what is the solution? In partnership with the Punjab Agricultural University, the Columbia Water Center conducted a pilot project to test several approaches that could reduce the amount of water consumed by rice farming. Of these, the most promising by far was providing farmers with a simple, $7 device that measures soil moisture in the ground.

This device, called a tensiometer, helped the farmers irrigate more precisely, and thus reduce water waste. As a result, the 525 farmers who participated saved an average of 22 percent. Based on these results, if two-thirds of Punjab’s rice farmers were to use the device, it would save the equivalent of 288 days of drinking water per person for the entire population of India and about 48,000 tons of carbon.

Of course one device alone can’t solve the water crisis; but this success shows that there are innovations that could make a very real difference. Now it’s just a matter of putting our minds to discovering and implementing them.

Columbia Water Center demonstrates research-based solutions to global freshwater scarcity and climate-related water risks. Follow Columbia Water Center on Facebook and Twitter

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