U.S. corn and soybean conditions deteriorated a bit further last week as wet conditions continued to negatively impact crops in the top producing state of Iowa.

USDA, in its weekly crop update, released on Tuesday afternoon, rated U.S. corn conditions 71% good/excellent, down from 73% a week earlier and unchanged from a year earlier. Traders had expected the U.S. rating to be unchanged from the previous week.

Nationwide soybean conditions were rated 66% good/excellent, down 1 percentage point from a week earlier and unchanged from a year earlier. On average, traders had expected a 1 percentage point improvement in the soybean rating.

Crops continue to develop much faster than last year and ahead of the normal pace. USDA reported that 19% of the U.S. corn crop was silking as of Sunday compared with only 8% last year and a five-year average of 12%. Some 23% of the soybean crop was said to be blooming compared with 13% a year earlier and the average of 20%.

Much of the deterioration in the U.S. corn crop rating was due to a drop of 7 percentage points in the good/excellent rating for the top-producing state of Iowa. The Iowa corn crop is now rated 65% good/excellent compared with 82% a year earlier.

Iowa soybean conditions slid two percentage points from a week earlier to 64% good/excellent compared with 80% a year earlier.

While dry weather last week helped Iowa field conditions, many areas were still suffering the negative effects of excessive moisture following heavy rains earlier in June, the Iowa office of the National Agricultural Statistics Service (NASS) reported.

“In low-lying fields where ponding occurred, corn and soybeans have been stunted or completely drowned out. Many places where crops were killed have already been re-planted; however sections that are still too wet may not be able to be replanted,” NASS said.

According to preliminary data from the Iowa Climatology Bureau, June precipitation averaged 10.45 in. statewide, or 5.81 in. above normal, ranking it as the wettest June ever in 138 years of state records.

Aside from ponded areas, corn and soybeans are mostly in good condition with corn beginning to tassel and soybeans are blooming, NASS said.

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.