WASHINGTON — The corn crop made a sizeable jump in its level of maturity in the week ended Sept. 22, but, like harvest progress, it lagged significantly behind the 2008-2012 average, the U.S. Department of Agriculture said in its most recent Crop Progress report.

A total of 40% of the crop was mature in the latest week, up from 22% the previous week but down from the 55% five-year average, the U.S.D.A. said.

Harvest in the week ended Sept. 22 was only 7% complete, the U.S.D.A. said, up from 4% the previous week but well below the five-year average of 16%.

The corn crop’s condition improved in the latest week, the U.S.D.A. reported. A total of 55% of the crop was rated good to excellent in the 18 major states, up from 53% the previous week. A total of 16% of the crop was rated very poor to poor, down from 18% the previous week, the U.S.D.A. said.

The soybean crop began harvest in the week ended Sept. 22, the U.S.D.A. said, somewhat behind schedule because of late planting. A total of 47% of the crop in the 18 major states was dropping leaves, down from the 56% five-year average, and 3% was harvested, down from the five-year average of 9%, the U.S.D.A. said.

The condition of the crop in the 18 major states was about identical in the latest week compared to the previous week, with 50% rated good to excellent, 33% fair and 17% very poor to poor, the U.S.D.A. said.

The spring wheat harvest in the six major states was close to complete and on par with the five-year average, the U.S.D.A. said. A total of 93% of the crop was harvested as of Sept. 22, identical to the five-year average.

Winter wheat plantings in the 18 major states stood at 23% as of Sept. 22, down a percentage point from the 24% five-year average, the U.S.D.A. said.

A total of 45% of the rice crop in the six major states was harvested as of Sept. 23, down from the 53% five-year average for the date. A total of 71% of the crop was in good-to-excellent condition and only 2% was rated very poor to poor, the U.S.D.A. said.