Corn (or maize as it is commonly called in many countries) is a major cereal grain grown in the United States. Corn is widely believed to have been domesticated (adapted for agricultural use) in Mexico as early as 9,000 years ago. The crop makes up over 95 percent of the feedgrain produced in the United States (grain grown for feeding to livestock). Corn is a major source of feed for beef and dairy cattle, swine and poultry. In recent years there has been a substantial increase in the use of corn to produce alcohol (ethanol) for fuel use (see chart). The distillers’ grains, which are a by-product of the process of making ethanol, are also fed to livestock.

Corn places heavy demands on the soil. The plant needs lots of nitrogen to produce good yields. As a result, corn is often grown in rotation with other crops, particularly soybeans, which also grow well in the same climatic conditions as corn. Soybeans are leguminous, which means that their root systems contain bacteria that transform nitrogen from the atmosphere into a form that can be used by plants. If soybeans are grown on a plot of land one year and corn is grown on that land the next year, the amount of nitrogen fertilizer that has to be added to the soil to produce corn is reduced.  Crop rotation has other advantages, such as controlling bacterial and fungal diseases and pests that can build up if the same crop is produced year after year on the same piece of land.

So it is perhaps not surprising that we see a similar pattern for the location of soybean production in the United States as we do for corn. In this case, in addition to climate and soils, good farming practices have a lot to do with the location of production of this crop.

Wheat is another crop for which location is influenced strongly by climatic conditions. The map of climate zones shows as that you move westwards from the Corn Belt states, precipitation declines. Corn is generally not grown in areas receiving less than 25 inches (60 cm) of annual precipitation; for high yields at least 18 to 20 inches (45 to 50 cm) of moisture should be available during the growing season. Wheat, on the other hand needs only 12 to 15 inches (31 to 38 centimeters) to produce a good crop. Wheat grows best when temperatures are warm, from 70° to 75° F (21° to 24° C), but not too hot. Wheat also needs a lot of sunshine, especially when the grain is ripening. Areas with low humidity (humidity is often high during the summer in the Corn Belt) are better since many wheat diseases thrive in damp weather.

So as we can see from the map wheat tends to be grown in drier areas in the United States to the west of the Corn Belt. Again, climate is a big factor in the location of production.

Another crop for which location is influenced strongly by climate – and in particular the lack of moisture is sorghum. Sorghum is a drought-tolerant and heat-tolerant plant that can be fed to livestock as an alternative to corn. Sorghum requires much less water than corn so it tends to be produced where water is scarce. Kansas is the leading state for producing sorghum (it is called milo by farmers), and the crop is also popular in Texas, where moisture is often scarce.

Some crops require a lot of water to grow in addition to high temperatures. One such crop is rice. Although the United States accounts for less than two percent of the world’s rice production, it ranks among the top five rice exporting countries. The leading rice producing state of Arkansas is able to obtain the large amount of water that the crop needs from the Mississippi river. The second leading state (California) uses irrigation to produce the crop. Other rice-producing states are Louisiana, Mississippi, Missouri and Texas. So in this case crop location is partly due to climate, but also has much to do with geography – particularly the presence of relatively flat land and access to water that can be used to flood that land.

Another crop that needs a lot of water is sugar. The United States produces sugar from sugarbeet, the root of which contains a high concentration of sugar, and sugarcane, in which sugar is contained in the stalk. Sugarbeet needs a temperate climate, while sugarcane needs a tropical or sub-tropical climate.

The map shows two main areas in which sugarbeet production is concentrated. One is the Red River Valley that borders the states of North Dakota and Minnesota, and the second is in Northern Michigan. Both of these areas have cool climates that are favorable to the growth of this crop.

Sugarcane production is largely concentrated in the warm southern states of Florida, Louisiana and Texas. These states have access to water for the crop and the subtropical climate that it needs.

So the location of sugar production in the United States is also primarily related to geography and climate.