U.S. corn conditions improved slightly last week as the main Corn Belt continued to receive plenty of moisture, while soybean conditions deteriorated modestly due to the impact of excessive rains in some areas.

USDA rated the U.S. corn crop 77% good/excellent as of Sunday, up from 76% a week earlier and 70% a year earlier, while pegging soybean conditions at 73% good/excellent, down from last week’s rating of 75%, but up from the year-earlier rating of 66%.

U.S. soybean planting progress was pegged at 91%, one percentage point ahead of the five-year average and soybean emergence was estimated at 80%, also one point ahead of the average pace.

Corn conditions in the top-producing state of Iowa were rated 76% good/excellent, down only 2 percentage points from a week earlier, while Iowa soybean conditions were rated 73% good/excellent, also down 2 points from the previous rating..

However, the Iowa office of the National Agricultural Statistics Service (NASS) warned that many cornfields need an opportunity to absorb excess rain. “Corn has been characterized as turning yellow in wet areas, while dark green and reaching heights of 58 in. in other localities,” NASS said in its weekly update.

Heavy rains in short periods of time last week have led to erosion in Iowa, especially in fields that were tilled. Cropland with poor drainage or in low-lying areas is underwater.

While Iowa soybeans are emerging nicely, they are becoming highly concentrated with weeds, NASS said.

Nebraska is also dealing with problems due to excessive rains. The state office of NASS noted in its weekly report that heavy rains caused low land flooding in parts of central and northeast Nebraska.

Rainfall totals of 5-6 in. were common for the week in Nebraska’s central and northeastern counties, with extremes of more than 10 in. in a few locations.

In Illinois, the corn crop was rated 72% good/excellent as of Sunday, down from 73% a week earlier as some areas also continued to feel the impact of excessive rainfall.

Illinois crop development remained ahead of normal, however, with the average height of the state’s corn plants estimated at 28 in., compared with only 10 in. a year ago and a five-year average of 19 in.

Illinois soybean conditions improved to 68% good/excellent from 65% a week earlier.

Minnesota remains the garden spot of the Midwest. The Minnesota corn crop rating rose to 94% good/excellent as of Sunday, up from 92% a week earlier. The state’s soybean crop rating was down 1 point, but remained extremely strong at 93% good/excellent.

Editor’s note: Richard Brock, Corn & Soybean Digest's marketing editor, is president of Brock Associates, a farm market advisory firm, and publisher of The Brock Report.