The Quest For Sustainable Corn In Iowa
Ames, Iowa – They don’t call it “The Corn State” for nothing.
Within minutes of driving outside Des Moines, the landscape opens up. No hills. No buildings. Just farms. Sprawling farms, much of them planted with corn.
And those tiny green shoots emerging last month from the dark rich soil represent a vast bounty. In 2013, Iowa corn farmers grew nearly 2.2 billion bushels of corn on 13.1 million acres, more than any other U.S. state. This year’s production is expected to be even higher, despite a late start in planting and slightly lower corn prices.
Drive around the state and you see the signs of success: Shiny tractors. New equipment. “Buildings are well maintained, they’re buying new equipment and if farmers could find additional farmland to buy, many would.” said Matthew Liebman, professor of agronomy at Iowa State University in Ames.
Corn is the nation’s biggest cash crop by far. Imagine two Florida’s covered with nothing but cornfields. Or enough corn to fill a freight train longer than the circumference of the Earth.
Fueled by national ethanol mandates, livestock feed demand and growing exports, U.S. corn production has nearly doubled in the last 20 years, including a harvest of nearly 14 billion bushels last year. Only 10 percent of the corn is used for direct human consumption
But, as a new Ceres report released yesterday makes clear, there’s a hitch to the corn sector’s prodigious expansion: It is not sustainable, especially in regard to water quality and water use impacts, and the escalating ripples from climate change.
U.S. corn production today uses vast amounts of water and fertilizer, far more than any other agriculture sector. Bedazzled by high corn prices, record demand and generous federal subsidies, a growing number of Midwest farmers are forsaking traditional conservation steps, such as minimum tillage, crop rotations and use of cover crops, that would limit soil erosion, fertilizer runoff and water impacts. They are also expanding production into highly erodible and ecologically sensitive lands, oftentimes hillsides and wetlands. In wetter states like Iowa, there’s also been a sharp uptick in the use of underground tile drainage systems, which keep root systems dry by draining fertilizer-laden water directly into streams.
The financial toll from these unsustainable practices is adding up.
In Iowa, the biggest problem is nitrate pollution in streams, rivers and water supplies. Last summer, the regional drinking water facility in Des Moines saw record nitrate levels – well above the EPA’s allowable limit of 10 milligrams per liter – in both of its source waters, the Raccoon and Des Moines Rivers. “The highest levels we’ve ever seen,” said watershed advocate Linda Kinman, whose department ran the world’s largest nitrate removal facility at full throttle last summer to remove the pollutants.
Polluted runoff from U.S. cornfields is the single largest source of nutrient pollution to the Gulf of Mexico’s ‘dead zone,’ an area the size of Connecticut that is essentially devoid of life due to agricultural runoff.
Lack of water is another problem, especially in High Plain states such as Kansas, Texas, Colorado and Nebraska, which rely on fragile groundwater aquifers to irrigate their thirsty cornfields. The Ceres report shows that more than half of the country’s irrigated corn production, worth more than $9 billion a year, depends on groundwater from the Ogallala aquifer where groundwater supplies are already declining. California corn growers, who rely on both surface and groundwater irrigation, face similar pressures and are already being forced to let their fields go fallow due to the state’s devastating drought.
Unfortunately, climate change trends will likely add to these pressures. The National Climate Assessment forecasts more droughts and extreme heat in the High Plain states and more heavy rains and floods in states further north such as Iowa. “We’re already seeing a higher frequency of intense precipitation events,” Iowa State’s Liebman said, recalling the 16 inches of rain central Iowa saw over 11 days in August 2010.
Corn growers and policymakers are well aware of the industry’s wide-ranging water challenges, but finding comprehensive solutions is not easy.
All across Iowa, there are pockets of innovation. Tim Smith, who grows corn and soybeans on more than 500 acres in Eagle Grove, is using small woodchip bioreactors to capture nitrates that are running off his fields from tile drains. He’s also growing cover crops (cereal rye) each fall to cut down on fertilizer use. The cover crops “sequester and recycle the nitrogen rather than sending it down the tile drains,” Smith said.
Professor Liebman is using three- and four-crop rotations – principally, corn, soy, oats and alfalfa – on 22 acres of experimental fields to reduce herbicide and fertilizer use. The results are powerful. “We’ve been able to reduce herbicide use by 95 percent with similar weed control,” he said. “On average, we’re also using 90 percent less nitrogen and getting higher (corn) yields.”
But getting the rest of the industry to adopt these more labor-intensive practices is hugely challenging.
The biggest impediment is federal policies – such as ethanol fuel mandates, crop insurance subsidies and corn price supports – that incentivize growing corn on as many acres as possible with little regard for conservation.
“It’s mostly about how many acres they can cover and doing things quickly,” Liebman said. “The system does not penalize the wrong kinds of behavior.”
Weak state and federal rules for limiting polluted runoff from farms are another big problem. EPA and state of Iowa have both adopted goals for reducing nitrogen pollution by 45 percent, but compliance is completely voluntary.
Regulations for limiting groundwater withdrawals are also generally weak, although there have been some encouraging developments, such as Kansas passing a law in 2012 to remove a “use it or lose it” provision for water rights holders. The new statute allows groundwater rights holders to reduce their withdrawals in wetter years in order to access more water in drier years.
Perhaps the biggest catalyst for change could be the industry itself – in particular, the food, feed and energy companies who have an enormous stake in ensuring the long-term productivity and reliability of U.S. corn production. Companies such as Coca-Cola, General Mills and Unilever have all set goals to sustainably source all of their priority agricultural ingredients – including corn – by 2020.
“Sustainability in agriculture is really important to us, as we think about production in the future and doing so on a finite planet with natural resources under a lot of constraints,” said Jerry Lynch, General Mill’s sustainability officer.
“We don’t necessarily know how to grow corn, but we do have a good opportunity to influence suppliers,” added Jon Radtke, water resources sustainability manager at Coca-Cola North America, in an interview yesterday with the Associated Press.
Let’s hope these companies can be successful in a race against the clock.