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Posted 02.06.15
Posted 01.30.15


Iowa's Corn Production

When I drive across Iowa, is all that corn I see really sweet corn?

Most of the corn you see growing in fields across Iowa is field corn. Very little of it is Iowa sweet corn. According to the 2012 U.S. Census of Agriculture, Iowa harvested 3,393 acres of sweet corn. Most of the sweet corn grown in Iowa is sold within the state at farmers’ markets and roadside stands.

How much corn does Iowa produce?

In 2014, Iowa corn farmers grew almost 2.4 billion bushels of corn on 13.2 million acres of land. (Source: USDA)

The 2015 projections state Iowa will grow over 2.3 billion bushels of corn on 12.6 million acres of land. (Source: PRX)

What state produces the most corn?

Iowa has produced the largest corn crop of any state for almost two decades. In an average year, Iowa produces more corn than most countries. For example, Iowa grows about 3 times as much corn as a country like Mexico.

Why is corn Iowa's leading crop?

Corn has been the dominant crop in Iowa for more than 150 years! A number of factors contribute to make corn Iowa's number one crop:

  • Iowa has a growing season that is long enough and warm enough to suit corn production.
  • Iowa usually receives enough rain to support healthy corn production.
  • Iowa has deep, rich soils that suit corn's needs.
  • Iowa also produces lots of livestock whose waste includes nutrients that are key to fertilizing fields for better corn production.
  • A wide variety of corn hybrids are available that do especially well in Iowa's environment.


Planting Corn

When is corn planted?

Corn is planted when the soil is warm enough to germinate the seeds but not so early that the young plants are likely to be damaged by frost.  In Iowa, this can be in early April for the state's southern counties, but it can be several weeks later for the state's northern most counties.

Where does corn grow?

Corn grows on every continent except Antarctica. Most corn is grown in middle latitudes (between 30 and 45 degrees), about equal to the area north of New Orleans and south of Montana in the Northern Hemisphere.

How big is an acre?

Officially, one acre is 4,840 square yards or 43,560 square feet. To imagine how big that is, think of a standard football field, which is almost the same size.

How much corn is grown on one acre?

In 2014, Iowa corn growers grew an average of 178 bushels per acre. Nationally, the average is 171 bushels per acre. (Source: USDA January, 2015)

Harvesting Corn

When is corn harvested?

In Iowa, some farmers might begin harvesting corn by mid-September, but most of the harvest is likely to take place in October. In a cool year, when the corn matures more slowly, much of Iowa's crop isn't harvested until November. Harvest times can vary a good deal because different corn hybrids take different lengths of time to mature. Even when plants are physically mature, farmers might wait to harvest them until corn kernels have dried further so that the corn can be stored for longer periods of time.

How big is a bushel?

A bushel began as a measure of volume, but the accepted standard for a bushel of corn is now measured in weight: 56 pounds. That's for shelled corn (after the husks and cobs are removed). It is about the size of a large bag of dog food.

When corn is harvested, what happens to the cob and the husks?

Modern combines strip the husks off each ear and remove the kernels from the ears as part of the harvesting process. The combine spreads the husks and cobs back onto the field as it moves but keeps the grain in a holding tank until it can be unloaded into a truck. In the field, the cobs and husks are still valuable because they help maintain good soil fertility and structure, just as compost and mulch do in home gardens.

About the Corn Plant

Where does corn come from?

Corn is descended from a plant called teosinte, which still grows in Mexico, and the first corn plants seem to have appeared in Mexico. The earliest known ears of corn were tiny - only a few inches long.  Millenniums of breeding, first by Native Americans, then by early pilgrims and modern scientists, have resulted in bigger, fuller ears of corn and made corn one of the world's three leading grain crops.

How many ears grow on a corn plant?

Different corn plants have different numbers of ears, but much of the field corn grown in Iowa is bred to develop just one large ear rather than several incomplete ears. This approach usually yields better total production.

How many kernels are there on an ear of corn?

The number of kernels per ear can vary from 500 to about 1,200, but a typical ear would have 800 kernels, according to corn experts.

How tall is a typical corn plant?

A typical corn plant can be anywhere from 5 feet to 12 feet tall. Under good growing conditions in Iowa, plants are commonly about 8 feet tall by midsummer. A healthy corn plant's root system will reach about 6-1/2 feet into the ground!

Why are there silks on corn?

The silks on corn are essential for pollen from the tassels to fertilize the plant. Each silk will convey pollen to one site on a developing ear of corn, making it possible for that site to develop into a kernel of corn. If it's too hot in the summer, the silks can dry out before all the sites on a corn cob are fertilized. As a result, there will be gaps on that ear of corn where no kernels developed because they weren't fertilized.

Uses for Corn

How is Iowa's corn crop used?

Most of Iowa's corn crop goes into animal feed. In livestock feeding, one bushel of corn converts to about 8 pounds of beef, 15.6 pounds of pork, or 21.6 pounds of chicken. Iowa 's corn is also processed into starches, oil, sweeteners, and ethanol.

How much ethanol do you get from a bushel of corn?

Many ethanol plants now produce 2.8 gallons of ethanol and about 17 pounds of animal feed (distillers grains) from each bushel of corn. Corn and ethanol production are now so efficient that it takes less energy to grow the crop and process it than the amount of energy in the ethanol itself. See the Ethanol Section for more info.

Is it true that there's corn in hundreds of products?

Actually, thousands of products in a typical supermarket contain corn. For many years, the Corn Refiners Association (CRA) has conducted surveys by sending researchers into a typical supermarket to read all the labels and tally all the products containing corn ingredients. The last CRA study found corn ingredients in almost 4,000 products - and that doesn't count all the meat, dairy, and poultry products that depend on corn for livestock feed or the many paper products that don't have ingredient labels but do contain corn.

Where can I find products made from corn-based PLA?

The list of products and sources keeps changing as new PLA products are introduced. One source to check is the National Corn Growers Association website www.ncga.com. The Corn-Based Products section lists all kinds of products, not just PLA. Also, remember than any product marketed under the NatureWorks or Ingeo label is a PLA product. If you're still puzzled about a specific product, contact the Iowa Corn Promotion Board.

For more corn questions, call 515-225-9242 or email: corninfo@iowacorn.org

Buying Corn and Corn Products

Who should I contact to buy corn and corn products?

We partner with the U.S. Grains Council who can help connect you with a seller of grain. Below is a list of resources to help you through the process:

For a list of Iowa Suppliers:
Iowa Directory of Exports

For a list of U.S. Suppliers:
U.S. Grains Council - Commercial Grain Exporters

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