We’ve Got More Than Enough Corn

July 8, 2015 | 10:39 am
Ricardo Salvador
Director, Food & Environment Program

Nowhere is the power and prowess of agricultural science so evident as in the Midwestern Corn Belt. More of this nation’s economic success and global dominance is due to the corn plant than most Americans realize. In fact, the reason most of us can be oblivious to that very fact—as we busily flit about our non-agricultural lives—owes to the crop’s exceptional productivity and its congenial malleability to our purposes. Since the 19th century, when people of European descent settled the area that is now the Corn Belt (currently extending from western Ohio to eastern Nebraska), yields of the crop have more than quintupled per unit of land, and increased by more than 8 times per unit of labor. Visualize this compound advancement by imagining a farmer prior to 1930 laboring 25 hours per acre to produce 30 bushel baskets of 56 pounds of grain each—if lucky, compared with his counterpart today investing less than 3 hours to produce 170 bushels on that same acre. This is the result of scientific research and the entrepreneurial application of technology by farmers. The nation’s industrial development was enabled in large measure by this transformation, including the industrialization of the corn crop itself.

Pushing the accelerator on corn production

Most of this technological improvement accelerated with the introduction of corn hybrids in the 1930s, a scientific project by then half a century in the making. Mechanization followed, as did fertilizers, herbicides and insecticides, each investment in additional technology justified by the productive response of corn, the featured crop around which Midwestern agriculture specialized. Today the wave of technological development continues, with the adoption of packages of bespoke biotech seeds and herbicides, computerized field mapping, self-guided equipment and variable rate applicators that take their electronic directions from those maps coordinated with satellite positioning systems, and drones that facilitate field scouting. Add to this climate models that assess the risks and rewards of investment on the basis of meteorological records combined with weather forecasts and crop prices. Whereas agricultural extension agents worked over a decade to persuade farmers of the 1930s to adopt hybrid seeds, today’s industrial farmers know that it can be costly, if not inimical to their survival, to delay adopting new tech. At the core of this industrial system—by now an intertwined global network of equipment, seed and chemical purveyors, technical advisors, farm managers, chemical applicators, grain traders and processors—is the corn crop, steadily and dependably gaining 2 bushels per acre per year of productivity, with no sign of exhausting its productive potential.

In fact, that yield potential is still at least 3 times greater than the current national yield average, as attested by the 503.8 bushel per acre world record yield attained last year in Valdosta, GA by farmer Randy Dowdy. There is only one other crop plant that can compare: sugarcane—like corn, a giant grass plant. But—unlike corn, which has been made most productive in the globe’s temperate zones—sugarcane is a perennial thereby restricted to tropical and subtropical zones. I wanted to know the secrets of corn’s productivity when I went to graduate school at Iowa State University 35 years ago to study with the renowned researcher Brent Pearce. Dr. Pearce was leading an interesting field of research wherein physiologists would specify to breeders what traits they should select to improve crop performance. He and a colleague, Jim Mock, had published the specification of an ideal corn plant to optimize yield, an “ideotype” in the parlance of crop physiologists (agricultural scientists specialized in understanding how crops—communities of individual plants, as opposed to individual plants—function.) If you drive through the Corn Belt today, you will see that ideotype realized, 40 decades later, and flourishing across the landscape.

Corn: the ultimate designer crop

The agronomic objective for any crop is to bathe it in light, top to bottom, because it is light energy—through photosynthesis—that drives crop productivity. Because the energy content of sunlight is so high relative to the amount leaves can use to drive photosynthesis (even though corn is unusually adept at this too) it isn’t very productive to intercept most light at the top of a crop canopy and shade the remainder. The modern corn plant is 10 feet tall, with up to 20 leaves when fully grown. That height enables an architecture that separates leaves vertically, at successive levels in a deep canopy. Those leaves display nearly a square yard of area per plant. To intercept as much light as possible per unit of land area, up to 40,000 of these tall, slim plants are crammed onto an acre. This is how a typical corn stand can display about 6.5 acres of leaf area on a single acre of land. You would think this crowding would result in competition, shading and diminished productivity. After all, each additional plant on an acre signifies fewer resources—water and soil nutrients—for all individual plants in the stand, in effect creating drought and soil infertility. Having selected for maize plants that can tolerate these conditions, breeders have forged burly, hardy plants that are drought resistant and efficient users of nutrients. The whole crop stand is crowned by a small tassel, or male flower, which is so prolific in producing pollen that Mock and Pearce accurately predicted it could be shrunk considerably, thereby shading the crop stand less than the giant tassels of the past—while still adequately pollinating the crop.

Photo credit: a corn stand southwest of Ames, Iowa. Summer 2014. R. Salvador

A modern designer corn crop, outside Ames, Iowa. Photo: R. Salvador

These improvements have collectively added up to a devastatingly productive crop, which establishes earlier and grows faster than its predecessors. When I arrived in Iowa in August 1980, there was a folksy saying to track progress of the corn crop, which even then was becoming dated. The crop was supposed to be on schedule if it reached “knee high by the fourth of July.” Today’s turbocharged corn crop is more like shoulder high, 5 feet, by the fourth of July. In fact Midwestern farmers, and those of us who are madly in love with the crop, know that in the coming two weeks we will see one of the most amazing displays of its might. In this period of time it will double its height, and unfurl about 8 new leaves beyond the 12 already on display.

This is possible because, like all grasses, corn is modular. Each module, stacked upon another and called a phytomer, features an internode, a branch bud and a leaf. When the young corn plant is manufactured, the genetic program that directs the process specifies: make node, make branch, make leaf, make internode, rotate 180 degrees, repeat 20 times. This all happens very early, and is complete by the time that five leaves are displayed. The miniature parts of the entire vegetative structure are all in place in that young seedling. You’d hardly notice the corn crop at that stage in what would look like a still empty field as you whizzed by it in your car. Thereafter, all internodes elongate simultaneously, limited only by the amount of sunlight, carbon dioxide, water and nutrients the plant can invest in the process. The more it grows, the more leaf and root tissue it develops, the faster the process occurs. And now, in early July, we’ll see explosive growth, because 20 internodes are expanding simultaneously, culminating with flowering—the emergence of male and female flowers, tassels and silks, respectively—around mid-July.

Photo Credit: “How a Corn Plant Grows.” Iowa State University, Steve Ritchie and Garren Benson.

Exploded view of corn phytomers and components on the verge of tasseling stage. Photo: “How a Corn Plant Grows.” Iowa State University, Steve Ritchie and Garren Benson.

Unless we fix an error, corn will take over the world!

I’ll pick up this story again around that time, in a couple of weeks, and periodically through harvest time. But amid all this talk of productivity I should insert my sobering destination. During my final phases of study at Iowa State I encountered a technical difficulty. I was programming everything I knew about corn to create a simulation to predict yield. I was relying on data from the venerable Don Duvick, long-term vice-president of hybrid development at Pioneer Hi-Bred International. The numbers I needed were quite arcane, and no one had followed up on exacting research Dr. Duvick had conducted for his doctoral research in the 1950s, wherein he determined the patterns of cell division in corn kernels. As it happened, he had made an error in the way he reported his results, and this error threw my calculations. We were only 30 miles apart from each other, yet I was a lowly graduate student and he a member of the National Academy of Sciences, one of the eminences of our field, and I didn’t have the courage to contact him. When I met him a few years later, I realized I should have just phoned the gracious gentleman, and I would have spared myself many weeks of frustration. He was, incidentally, tickled that after 30 years I had been the first and only person to catch a technical error in his dissertation that he had become aware of too late, and which he’d long forgotten. But this is where initially accepting his erroneous figures led me: corn kernels theoretically would grow exponentially, without bound. As one of my professors told me when he reviewed my model: “Corn will take over the world!”

It is time to rethink the Midwestern corn production machine

And, actually, this is where we are. We have produced enough corn. And we cannot afford to ignore that fact and to rethink the Midwest’s corn production system. In tandem with the many benefits I’ve alluded here, many serious problems attend the overproduction of this crop. In itself, the crop is noble, the crop is historical; it is economically significant and life-giving, but it is also at the core of the most significant issues we must resolve in agriculture as well as as a society. These problems, it turns out, are the problems of industrialization: labor exploitation, economic inequality, extraction, pollution, overconsumption and the inertia that flows from needing to preserve and protect investment in infrastructure.

This production season, about 8 million acres of corn have not been planted due to weather. This might signify lower supply at season’s end and thereby higher prices for those corn farmers who were able to plant on time. But there is too much corn. There are many other overproducing corn belts around the planet, and weather and growing conditions there have been good thus far, leading instead to the prospect of lower prices, potentially below the cost of production. In the U.S., if that happens, we will take care of these corn farmers through government programs, keeping them in business to again attempt to overproduce a crop whose major purpose is to find a purpose (in the Midwest, the problem of what to do with all that corn is euphemistically referred to as the endless quest to “develop new markets.”)

As I continue to trace the continuing progress of the corn crop this production season, I’ll explore what it means to advocate for less corn production but not necessarily fewer farmers. The guide star in pursuit of these questions should be: “What do we need to do?” And not how to continue doing what we know to do so well, whether needed or not.

About the author

More from Ricardo

As the senior scientist and director of the Food and Environment Program at the Union of Concerned Scientists, Ricardo Salvador has over four decades of experience working with citizens, scientists, economists, and politicians to transition our current food system into one that grows healthy foods while employing sustainable and socially equitable practices.