The 2012 drought that struck Iowa and the rest of the Corn Belt this summer has grown worse, raising more concern about the 2013 crop growing season. According to the latest U.S. Drought Monitor map released by the National Weather Service on October 4, the epicenter of the drought has moved westward from Indiana and Illinois and is now in Iowa.
The map shows that as of last week, 75.3% of the state of Iowa was in extreme drought, up from 65.8% a week ago. State climatologist Harry Hillaker with the Iowa Department of Agriculture says to be effective in replenishing soil moisture in the top 5 feet of soil, rains need to fall by December 1, 2012. That's about when the usual freezing of Iowa's soils occurs for winter. After the ground freezes hard, rainfall and melting snow run off the fields instead of soaking into the fields.
"Moisture generally runs off of frozen ground," notes Hillaker. "The clock is ticking. We need some rain soon to build up the supply of reserve moisture in the subsoil for use by next year's crops."
Iowa's rainfall for 2012 through September is running 9.12 inches below normal
The cool front that dropped temperatures into the low 50-degree range late last week failed to bring much rain to the state. There were a few sprinkles in areas of Iowa but "the state's drought is persisting during the fall season, which is a crucial time to start to get some rain to replenish the soils that have been dried out by hot, dry weather we had this past summer," notes Hillaker.
Iowa's rainfall through the end of September totaled 20.57 inches which is 9.12 inches short of the 29.69 inches that's normal through the first nine months of the year. The 9.12 inch moisture deficit is the eighth largest on record in Iowa history, says Hillaker.