Corn harvest crept forward to 15% done and the soybean harvest inched up to 10% done as of Sunday, both of which were behind last year and the five-year averages, USDA said on Monday.

Related: Corn 9% harvested, soybeans 4%

Rain in Iowa was the biggest culprit to harvest progress as the state had downpours from southeast areas of the state to the northeast, which limited days suitable for fieldwork to 3.6. Other states fared better, with Illinois reporting 5.9 days suitable for fieldwork, Indiana 6.2, Nebraska 6 and Ohio 6.4.

The nationwide soybean harvest was 10% done as of Sunday. (Photo: fotokostic/Thinkstock)

While Iowa’s statewide average rainfall was 1.95 inches for the week, about 11 inches was reported in Nora Springs in north central Iowa. The statewide average for September this year is 6.29 inches, the highest for a September since 1986.

 “Excessive rains have raised concerns about crop damage and pasture condition in certain parts of the state,” Iowa said.

Iowa corn was 4% harvested, compared with 4% a year ago and the 11% average. Its soybeans were 4% harvested, compared with 5% last year and the 9% average.

National corn and soybean ratings were unchanged from a week ago at 74% good/excellent and 73%, respectively. The national average corn yield potential calculated by Farm Futures based on the condition ratings was unchanged at 174.1 bushels per acre. The yield potential increased in the past week in four states, decreased in eight including Iowa and was unchanged in five.

The calculated soybean yield potential was unchanged at 50.3 bpa. Soybean yield potential improved in nine states, was unchanged in four and declined in five from a week ago. The declines included minor slippage in Iowa.

Winter wheat planting advanced to 30%, compared with 28% a year ago and the 30% average. Wheat emergence was 8%, versus 6% a year ago and the 8% average.

In Kansas, the winter wheat was 20% planted and 3% emerged, which matched last year, but trailed the the five-year averages. Statewide topsoil moisture was rated 12% surplus, 75% adequate, 10% short and 3% very short.

Nationally, sorghum was 34% harvested and 61% mature versus the 32% and 52% averages. The crop rating was unchanged at 66% good to excellent.