The percentage of Iowa’s corn and soybeans rated good or excellent declined at least 7 points last week, the largest such drop this year amid worsening drought conditions, according to U.S. Department of Agriculture reports.
The latest USDA report on Monday said 66% of the state’s corn and 63% of soybeans were good or excellent, down from 73% and 71% a week ago.
That’s a reduction of 7 and 8 percentage points, respectively.
Widespread moderate and severe drought conditions are affecting much of southern Iowa, where the available soil moisture for crops is dwindling. Less than 10% of topsoil and subsoil in southwest Iowa has adequate moisture, the USDA report said.
The opposite is true in northeast Iowa, where 90% of the soil has adequate or surplus water. Generally, in the past two weeks, northeast Iowa has had above-average rainfall and southwest has been abnormally dry.
“Weekly precipitation totals ranged from no accumulation at multiple western and southern Iowa stations to 3.67 inches in Anamosa,” Justin Glisan, the state climatologist, wrote in his weekly weather report that published Monday.
The state as a whole received less than half the rainfall of what is typically expected last week, Glisan said, and less than half the state has adequate soil moisture.
The area of worst drought is still in northwest Iowa near Sioux City, although the amount of land classified under extreme drought shrunk slightly in the U.S. Drought Monitor’s report late last week. A new report is due Thursday.
Although crop conditions have declined significantly this growing season, their ratings are still better than a year ago, and that corn set an all-time yield record.
In the Aug. 16, 2021, report by the USDA, corn was 58% good or excellent. The state’s average yield that year was 205 bushels per acre. Last year’s yields were saved by timely rains amid an otherwise dry planting and growing season.
A year before that, in the Aug. 17, 2020, report, corn was slightly better at 59% good or excellent, but the state’s average yield was 177 bushels per acre.