Concentration of corn and soybean production in the U.S.
Concentration of corn and soybean production in the U.S. is examined in this article. As is well known, corn and soybeans production is concentrated in the Corn-belt, with significant amounts of production occurring in the upper Midwest, parts of the Great Plains, and down the Mississippi River.
Data and Methods
Concentration is examined for both corn and soybeans. The following describes methods for corn. The same procedures were used for soybeans.
Total corn production by county came from the National Agricultural Statistical Service (NASS) for 2010, 2011, and 2012. These three years were averaged to arrive at average production for each county in the U.S.
Based on the 2010-2012 average, counties were ranked ordered from highest to lowest production. Then, production totals were calculated for successively more counties. For example, production from the first and second largest counties were added together to arrive at production from the two largest counties. Then, production from the three largest counties was added together to arrive at production for the three largest producing counties. This process was repeated until the total from the largest counties just exceeded 50% of total U.S. production from 2010 to 2012. These largest counties then accounted for 50% of total U.S. production. The resulting 220 counties for corn are denoted as dark green in Figure 1.
The above process was repeated to find the largest counties accounting for 75% of production. In Figure 1, the resulting 456 counties include the dark green counties representing 50% of total production plus the light green counties. The process was repeated for 90% of total U.S. production. The resulting 753 counties are denoted by dark green, light green, and yellow in Figure 1.
The above procedure results in the lowest number of counties that account for the specified level of U.S. total production. It does not attempt to control for size of county. The above procedure may have a bias for counties with more acres. A procedure holding acreage constant could result in a different map to the one shown in Figure 1. However, large differences from that shown in Figure 1 are not likely.
In the U.S., 50% of the corn is produced in the 220 counties with the largest production. These counties are predominately located center of the Corn-belt (see Figure 1). States in the Corn-belt with counties in the top 50% of production include Iowa (66 counties), Illinois (43 counties), Minnesota (37 counties), Nebraska (35 counties), South Dakota (11 counties), Indiana (7 counties) and North Dakota (6 counties). Other states that have counties in the 220 include Wisconsin (6 counties), Texas (2 counties), Kansas (3 counties), Colorado (3 counties), and Missouri (1 county).