A west-coast friend asked recently why Iowa farmers grow mostly animal feed, instead of food for human consumption like they do in California. 

It’s a fair question. 

Iowa has some of the most productive farmland anywhere. But our two commodity crops – corn and soybeans – feed animals, not humans.

There was a time when Iowa farmers grew a variety of fruits and vegetables. In fact, 100 years ago, many Iowa communities canned sweet corn, cucumbers, tomatoes and other produce. 

But that largely disappeared after World War II. 

Growing up in the 1950s, I had heard stories about how the early-November, Armistice Day Blizzard of 1940 had changed the face of Iowa agriculture by wiping out many orchards and vineyards.  

Damage from that blizzard was considerable, agreed Paul Lasley, Iowa State University’s preeminent rural sociologist. But, he added, “It wasn’t a set thing. Several things happened.” 

One was the gradual loss of farm labor that resulted from a rural-to-urban migration that began during Iowa’s farm depression of the 1920s and accelerated during the Great Depression of the 1930s.

“People were tired of low incomes and hard work,” Lasley said. “World War II provided temporary relief from low farm prices, but at the close of the war, agriculture went into another slump.”

By then, other changes were afoot. 

One was the mechanization of farming. It had begun in the 1920s but was greatly expanded by technologies developed during the war, including continuous improvement of the internal combustion engine, Lasley said. 

By the end of World War II, he noted, steam-powered farm equipment had been replaced with gasoline- and diesel-powered tractors. Self-propelled combines followed, allowing farmers to cultivate more acres with substantially less labor. 

Another change that predated the war was Henry Wallace’s invention of hybrid seed corn. Wallace’s new seeds produced more consistent and larger yields, and the popularity of hybrid seeds led farmers to form marketing cooperatives, which focused on promoting corn.  

After the war, corn got another big boost when farmers learned that the more nitrogen they put on a field, the better the yield. 

The modern fertilizer industry was launched when munitions manufacturers discovered their wartime nitrate factories could also produce nitrogen for anhydrous ammonia, the main ingredient in fertilizer. 
  
We now know there are significant downsides to anhydrous ammonia and what it does to farm fields over time. But that is a separate story, which I’ll come back to in a future column. 

One of the most significant changes that occurred during the Great Depression was a softening of attitudes toward public investments in infrastructure. 
The hardships of the depression years opened people’s minds about whether and how government could encourage private sector growth.

One post-war investment that produced seismic changes for agriculture involved transportation.  

During the war, Gen. Dwight Eisenhower had seen how effective German highways were as a war weapon in the movement of men and materials to where they were needed. 

When Eisenhower became president in 1953, he used the same logistics skills he had acquired during the war and his knowledge of German infrastructure to improve U.S. transportation systems.

Eisenhower’s Interstate Highway system, along with improvements in rail and river transport, moved goods around the country quickly, which encouraged private-sector specialization. 

For agriculture, specialization was different in Iowa than it was in California. 

In Iowa, where mechanization had replaced farm labor, the new transportation systems helped move large quantities of grain to world export markets.

In California with its large supply of low-wage labor, specialization meant increased efficiencies in the  production, processing and distribution across the entire continent of food for human consumption. 

The agriculture we have today is the product of political and economic histories, as well as geological and demographic evolutions.