Comparing the 2012 drought to other droughts
The National Agricultural Statistics Service provides yield data for 9 districts in Missouri. I calculated trend line yields and yield losses for 1983, 1984 and 2012 droughts. Because many farmers said that the weather in 2012 reminded them of 1988, I included that year, also. The south central region was not used because total soybean production is relatively low in that region. Figure 4 is a graph of yield losses expressed as a percentage of time line yields for each region in each of the four selected years.
click image to zoom As I stated in Part 1, summer weather conditions often vary widely across Missouri. An extreme example is the summer of 1993. In that year, SE Missouri experienced drought conditions in July and August while heavy rains were common in central and north Missouri. Farmers in SE Missouri were irrigating crops and increasing levee heights to accommodate northern rains at the same time and in the same fields.
In 1983, yield losses of greater than 26% occurred in all 8 regions. The year ranked #1 among all years for soybean yield loss. Most regions exhibited even greater soybean yield loss in 1984 than in 1983. The exception was SE. Estimated soybean yield loss in 2012 will rank #3 among years and is only 2 percentage points less than 1983 and 1984. The pattern for estimated yield losses among the 8 regions in 2012 is quite variable. USDA/NASS estimates that soybean yield loss did not occur in SE, is less than 20% in two regions, and 30% or greater in four regions. According to the Drought Monitor, SE Missouri experience exceptional drought for much of the late spring and summer of 2012. Although soybean irrigation is common in SE Missouri, the lack of a yield decrease is surprising and may be optimistic.
Many farmers said that the weather in 2012 reminded them of 1988. Statewide, the soybean yield loss in 1988 was only half of the yield loss in 1983 and 1984. The 1988 yield loss ranks 8th among yield losses for the past 50 years. The stressful weather and soybean yield losses in 1988 were located primarily in northwest and eastern Missouri.