The United States' most important crop, corn, is grown on a massive scale. The size of the crop influences environmental health, the country's food system and diet and what fuels the nation's automobiles. This series explores corn's role in contributing to factory farmed meat and obesity, how little of the crop gets directly eaten by people and how the corn industry got so big in the US.
Over 90 million acres (140,000 sq. mi., or the size of Colorado and New York combined) of cropland is used to produce corn. With the rise of corn ethanol production in the US now consuming 40 percent of the crop each year (up from less than one percent in the early 1980s), the trend is for additional acreage devoted to corn production. The US's devotion to corn has led to an increased strain on resources and created an industry dedicated to increasing yields.
Corn and Technology
Historically, corn has always been an important crop in the US, but practices to boost yields didn't take off until the 1920s and 1930s. Scientists realized corn hybrids could create larger ears and be grown closer together to produce more corn per acre. Chemical companies began producing industrial-scale volumes of nitrogen fertilizer, and farm equipment manufacturers enhanced farm machines that improved the efficiency of sowing, spraying and harvesting. Within decades, productivity per acre doubled, and then continued to rise except in years with extreme weather events. Seed companies also transformed from 'mom and pop' operations to the domain of large agribusinesses.
Seed modification didn't stop with hybrid corn varieties. In the second half of the 20th century, scientists began to understand DNA and genetics. In the 1970s and 1980s, scientists began to create genetically modify organisms (GMOs) to produce specific attributes. In 1996, Monsanto produced the first commercial genetically modified (GM) corn, known as "Roundup Ready." This GM corn was designed to tolerate the use of the company's herbicide, glyphosate (aka, Roundup). Another type of GM corn, Bt corn, was designed for the plant itself to produce an insecticide. Some companies are also looking at drought resistance and virus and fungus protection as the next type of GM corn to be commercially produced.
Concerns Over Genetically Modified Corn
With the rise of corn monocultures, there are increasing concerns about GM varieties. The USDA reported that in 2015, 89 percent of US corn acreage consisted of GM herbicide-tolerant strains and 81 percent of corn acreage was insect resistant (Bt toxin). Furthermore, GM corn that has more than one GM trait (i.e., stacked seeds) was planted on 77 percent of acreage in 2015, up from one percent in the year 2000. (Stacked varieties of corn tend to have higher yields.) Crops with GM traits have allowed the risk of insects and weeds becoming resistant to these specific insecticides and herbicides. Facing concerns with GM crops, many countries in Europe and Africa have strict regulations on GM organisms that include some bans on growing GM crops.
In the US, GM crops have changed part of the game with the chemical warfare with pests. With the widespread planting of GM corn containing insecticide traits, there is some evidence that certain insects are becoming more resistant to Bt toxins. Farmers are attempting to delay resistance by planting non-Bt seeds, supplementing with additional insecticides and planting GM varieties with two Bt toxin traits. Bt toxins target lepidopteron species (i.e., in the caterpillar phase of a moth or butterfly); outside of that order of insects, there has not been much of a detrimental effect on non-target species, but there is some evidence that Bt traits affect non-pest butterfly species like monarchs.
In an effort to prevent insects becoming resistant to the GM corn's insecticide, the EPA has an Insect Resistance Management program that requires a 20 percent non-GM corn refuge to be planted with the GM variety. Some farmers use a "refuge in a bag" seed strategy, but there is some evidence that due to pollen drift, the non-GM plants may contain low doses of the Bt trait, which may speed up insects becoming resistant.
To fight weeds, herbicide-tolerant GM corn was designed to avoid the lethal effects of certain types of broad spectrum herbicides. Beginning with Roundup Ready corn in 1996, widespread application of glyphosate across corn and soybean fields has now created certain weeds that have become glyphosate resistant. Companies and institutions have or are in the process of designing alternative or additional herbicide-tolerant GM traits, thus prolonging the genetic arms race in the chemical war on weeds.
Monocropping and Loss of Biodiversity
With the USDA expecting the 2016 corn crop to increase to 93.6 million acres, there are growing concerns about planting such a large monoculture. The Irish potato famine and the threat to international banana production tell cautionary tales that a single pathogen could cause widespread havoc when there is a lack of crop diversity. Also, the increasing size of the crop adds to environmental impacts, like the loss of grasslands. Less land is set aside for ecological conservation, more topsoil is disturbed and is susceptible to erosion, soil quality could become degraded and fertilizers that run off the land contribute to nutrient pollution. The industrialization of corn has certainly increased yields but has come at a cost of preserving environmental and public health.