More: For the latest crop ratings, view the Sept. 15, 2014, USDA crop progress and condition update.
U.S. corn's rating was unchanged from a week ago at 74% good to excellent, but development remained behind with 15% mature versus the 26% average, USDA said in its latest weekly crop ratings released on Monday.
Soybeans were unchanged at 72% good to excellent, while crop development was slightly behind with 12% dropping leaves, compared with the 17% average.
In Iowa, the top corn and soybean producer, corn was 6% mature versus the 27% average, while 3% of the soybeans were dropping leaves versus the 10% average.
USDA did not post national harvest readings for corn or soybeans, but some harvest was underway, with Kansas corn 12% cut, versus the 6% average. In Mississippi, corn was 61% cut and soybeans were 17%.
Spring wheat harvest still behind
Spring wheat harvest at 58% trailed the five-year average of 78%, as late-season rain delayed the start of harvesting.
In North Dakota, the largest producer, harvest was 42% done versus 70% a year ago and the 74% average. More rain in the state this past week to interrupt harvest, with the northern areas receiving the most.
North Dakota's spring wheat was rated 74% good to excellent, while the overall U.S. crop rated 60% good to excellent, down from last week's 63%. Wheat in Washington and Idaho continued to have the lowest ratings.
Winter wheat was 3% planted, compared with the 4% average. Kansas, the top wheat producer, was 2% planted, Texas was 3% and Oklahoma 2%.
The Kansas state report said storms brought much needed rain for the wheat, but they delayed the corn harvest. Statewide topsoil moisture improved to 66% adequate to surplus, 25% short and 9% very short, from the previous week's 54%, 32%, and 14%.
Cotton: 39% bolls open, 49% good to excellent
Bolls were open on 39% of the cotton, compared with 23% a year ago, and the 37% average. The crop was rated 49% good to excellent, down from 50% a week ago and 45% a year ago.
Oats were 86% harvested, compared with 96% a year ago and the 97% average. Sorghum was 40% mature and 26% harvested, versus the respective averages of 33% and 25%. It was 57% good to excellent versus 57% a week ago and 54% a year ago.
Rice was 26% harvested compared with 23% a year ago and the 36% average. It was rated 74% good to excellent, unchanged from a week ago, and up from 71% a year ago.