Last week Tidbits highlighted the history of corn production in Nebraska. This week the focus turns to soybeans. The two-part series was prompted by forecasts and discussions on how U.S. cropping patterns might differ in the future with climate change, causing one to ponder how cropping patterns in Nebraska might have changed in the past. To investigate, USDA National Agricultural Statistics Service (USDA NASS) corn and soybean production data by county was examined between 1970 and 2020. Each county’s share of state production was calculated for ten-year increments and counties with a production share of at least 2 percent were defined as top-producing counties. Maps were developed for each 10-year increment highlighting the top-producing counties. The darker a county is shaded, the greater the county’s share of production.
Maps illustrating the evolution of the top soybean producing counties since 1970 can be seen in Figure 1. Soybeans were a relatively new crop to the state in 1970 with a total production of just 18 million bushels. The top soybean producing counties that year bordered the Missouri River with a few counties in the northeast sprinkled in. Dodge and Saunders Counties had the largest shares of state production at 7.7 percent and 5.7 percent respectively. Beginning in 1980 Saunders County was the top-producing county every decade until 2020 when Gage County rose to the top. After 1970, the top soybean producing counties drifted westward, with the peak of the western migration occurring in 2000 when Holt County and a few counties in the south-central region made an appearance among top-producing counties. The top counties subsequently migrated back eastward, and by 2020, the top-producing counties were located in a corridor one or two counties removed from the Missouri River in the eastern third of the state.
There were 19 top-producing counties in 1970 which collectively accounted for 71 percent of the state’s soybean production. In 1980, top-producing counties numbered 21, accounting for 75 percent of the state total, the highest concentration of production in the top-producing counties during the 50-year period. Since then, the share of production accounted for by top-producing counties declined so that by 2020 18 counties accounted for just 42 percent of production. Soybean production in 2020 was 294 million bushels, 16 times greater than 1970 production. Gage (2.91 percent), Saunders (2.88 percent), and Platte (2.56 percent) were the largest soybean producing counties. In fact, 2020 production in Gage and Saunders County alone nearly matched state production in 1970.
Interestingly, there wasn’t much overlap between top corn and soybean producing counties over the past 50 years. The top corn producing counties have been located along the Platte River in east and central Nebraska while top soybean producing counties have been nearer the Missouri River. The reasons probably lie in access to irrigation water, topography, economics, and few other factors influencing crops’ suitability to an area. Top corn producing counties have greater access to water and are some of the state’s most irrigation-dense counties. Top-producing soybean counties are more dryland dominant. This is likely the result of soybeans being more economically competitive with corn in dryland conditions. Also, the eastern third of the state and the Missouri Valley tends to be hilly with smaller fields and terraces which isn’t as conducive to irrigation.
To finish, the top corn and soybean producing counties in the state over the past 50 years have remained remarkedly geographically stable. And, at least through 2020, climate change doesn’t appear to have affected the suitability of corn or soybean production. This isn’t to suggest that it won’t, just that any effect hasn’t appeared yet. There are limitations to this analysis. First, it only provides snapshots of top crop producing counties every 10 years creating a risk that unusual events (drought or flooding) distorted the production for a given year and distorted the analysis. Also, the analysis only focused on top-producing counties. Ignoring changes among other counties could miss trends in corn or soybean production. Finally, the analysis relies on USDA NASS county production data. Unfortunately, there are years with missing data. If the data for a particular county was unavailable in one of years examined, it could be the county was overlooked that year.
Figure 1. Counties with At Least 2% of State’s Soybean Production
* Counties highlighted accounted for at least 2 percent of state’s total soybean production in that year. The darker the county, the greater the share of production.
Source: NEFB graphics based on USDA NASS data