Corn harvest advanced to 35% done and the soybean harvest improved to 44% as of Sunday, with both 3 points behind the five-year averages, USDA said on Tuesday.

Crop ratings were unchanged for corn and soybeans, with corn at 73% good to excellent and soybeans at 74%.

Related: Corn 24% harvested, soybeans 26%

Rain and muddy fields slowed harvest in Iowa, where there were 4.5 days suitable for field work. Corn there was 19% harvested and soybeans 43%, compared with the respective 32% and 54% five-year averages.

The national average corn yield potential calculated by Farm Futures based on the condition ratings were about unchanged with a topside forecast of 173.3 bushels per acre.

Conditions were better in neighboring Illinois, where corn harvest advanced to 62%, which was well ahead of the 51% average. There were 5.6 days suitable for fieldwork, which included winter wheat planting, that reached 20%, compared with the 30% five-year average.

Harvest in Indiana had a slow start last week because of wet fields, but dry weather had farmers in the fields later in the week, the state said. Indiana’s corn harvest was at 38% versus the 33% average while soybeans were at 33% versus the 36% average.

“While the dry week was beneficial for harvest progress, it had little impact on the disease and mold presence that remains in the fields. Stalk strength continues to be a concern during harvest, but the overall condition of the (corn) crop remains stable,” Indiana said.

The national average corn yield potential calculated by Farm Futures based on the condition ratings were about unchanged with a topside forecast of 173.3 bushels per acre. Calculations show yield potential increased the past week in six states, decreased in five and unchanged in six.

The calculated soybean yield potential also was unchanged at about 50.5 bpa. Soybean yield potential improved in 10 states, was unchanged in four and declined in four from a week ago.

Winter wheat planting advanced to 59%, compared with 60% a year ago and the 60% average. Wheat emergence was 34%, versus 29% a year ago and the 30% average.

In Kansas, winter wheat was 58% planted and 29% emerged, which trailed the five-year averages. Statewide topsoil moisture was rated 12% surplus, 73% adequate, 11% short and 4% very short.

Nationally, sorghum was 48% harvested versus the 42% average. The crop rating slipped 1 point to 65% good to excellent.