Signup to receive email updates

or follow our RSS feed


Angie Peltier

Angie Peltier
Former Extension Educator, Commercial Agriculture

follow our RSS feed

Blog Banner

Hill and Furrow

Current topics about crop production in Western Illinois, including field crops research at the NWIARDC in Monmouth.
Figure. Deviation from normal of 2012 precipitation at the NWIARDC.
click image to view 2 more

Hot dry weather conditions and yield implications

The USDA-National Agricultural Statistics Service (NASS) released their Weekly Weather and Crop Bulletin on June 5th. In this report, climatologists from the National Drought Mitigation Center released their drought monitor survey. These experts are confirming what we all have been feeling, 86.1% of Illinois is experiencing abnormally dry conditions, 16.5% is experiencing moderate drought and 6.3% severe drought conditions (Figure). The only area of the state that seems to have escaped these conditions, at least temporarily, is portions of the Northeastern and Eastern regions.

In the Western region, we are experiencing abnormally dry conditions with 59% experiencing top soil with short moisture ratings. The National Oceanic and Atmospheric Administration (NOAA) and USDA jointly released their Crop Moisture Index map for June 2nd, which they explain is a map of short-term crop need versus available water in a shallow soil profile. The Western region currently has an index of -3. This means that the typical farm field is abnormally dry and yield prospects are reduced. This index changes on a weekly basis throughout the growing season.

Weather data from the NWIARDC is no different (Tables). Every month of 2012 received below average precipitation and above average temperatures (Figures). These two factors along with other factors such as wind speed, weed pressure, and water needs of the growing crop plants all work to decrease available soil moisture.

Crop condition is on everyone's mind

Dr. Emerson Nafziger , University of Illinois Agronomist, wrote about this topic in a recent Bulletin entitled, "Early season crop ratings and yield". In this article he discusses the relationship between the percent of corn rated good or excellent in May by the USDA-NASS and corn yields. He also talks about how corn that is stressed early on often yields  well if the stress is limited to early in the growing season.

Drs. Darrel Good and Scott Irwin of the University of Illinois Department of Agricultural and Consumer Economics also explored this topic in a recent farmdoc Daily article entitled, "Recent observations on the tolerance of corn yield to drought conditions". In this article they examine three different data sets: 1) Irrigated corn yields in Texas, 2) Average corn yield in Argentina, and 3) Illinois data. Using an admittedly small sample size, they conclude that corn yields in the US may be a little less susceptible to drought stress than in years past.


Soil Temperature

Air Temp

Growing degree units

4" (Bare)

4" (Sod)



Monthly average high


Monthly total: 537



Monthly average low




Observed high (date)

95 (28)

29 (28)

89 (28)

77 (18, 28)

Observed low (date)

45 (1)

3.5 (1)

56 (1)

53 (2)

2012 PRECIPITATION (in inches)

Since January 1


Monthly Total

Monthly departure from average

Total accumulation

Total departure


























Please share this article with your friends!
Share on Facebook Tweet on Twitter Pin on Pinterest


Email will not display publicly, it is used only for validating comment