There was quite a bit of talk that some dry conditions in parts of the corn and soybean growing areas in the U.S. may depress yields, especially in sections of the Eastern Corn Belt where heavy spring rains may have led to some shallow rooted plants.
This graphic shows August 2015 rainfall in inches for the top 21 corn and soybean producing states and the U.S. in inches along with their respective 1986-2015 average.
The August 2015 rainfall as a percent of this 30 year average is also plotted for these states and the U.S.
We key in on these states that had less than 75% of their normal August rainfall and this includes IN at 71.6%, LA at 56.3%, MS at 72.1%, NC at 74.4%, ND at 69.4%, OH at 73.4%, PA at 66.1% and TX at 60.0%.
Most of the states are in the Eastern Corn Belt and the south.
Interestingly, dry August conditions here had no impact on corn yields with LA, PA and TX having no change in yields from the August to the September report.
OH was off 5 bushels per acre (bpa) and IN was off 2 bpa with ND actually 2 bpa higher.
There were even fewer changes for the soybeans with LA off 2 bpa and NC down 3 bpa and ND down 1 bpa.
OH soybean yields were actually unchanged and IN was 1 bpa higher.
Keep in mind that while rainfall was below normal in a number of states, much of the key U.S. corn and soybean growing regions saw below average temperatures all summer that continued into August while subsoil moisture levels were more than adequate in almost all of these 21 states.