WASHINGTON — A total of 11% of the soybean crop in the 18 major states advanced to the stage of dropping leaves by Sept. 8, the U.S. Department of Agriculture said in its latest Crop Progress report, down from 19% as the 2008-12 average on the same date. The report issued Sept. 9 was the first official update on how much of the crop was dropping leaves, an indication of the soybean crop’s maturity.

Market participants have been nervous that the crop may be experiencing significant stress from the ongoing hot temperatures and meager rains in the nation’s midsection. The data in the report, though, indicated that the soybean crop was on track, broadly speaking, despite having been planted relatively late and lagging some five-year averages.

The condition of the crop declined modestly in the latest week, the U.S.D.A. said. In the 18 major states, 52% of the crop was rated good to excellent as of Sept. 8, down from 54% the previous week but up significantly from 33% on the same date a year ago, when the U.S. was in the grips of a serious drought.

A total of 16% of the crop was rated very poor to poor in the latest week, up from 15% the previous week but down from 35% a year ago, the U.S.D.A. said.

Corn also advanced toward maturity despite lagging five-year averages and experiencing modest declines in crop condition.

The U.S.D.A. said 64% of the crop had reached the dent stage as of Sept. 8, down from a 75% five-year average. A total of 9% of the crop in the 18 major states was deemed mature, down significantly from a 28% five-year average.

The U.S.D.A. said 54% of the crop was in good-to-excellent condition as of Sept. 8, down from 56% the previous week but up from 22% in the drought year of 2012. A total of 17% of the 2013 crop was rated very poor to poor, up a percentage point from the previous week.

A total of 5% of the new hard red winter wheat crop in the 18 major states was planted in the week ended Sept. 8, the U.S.D.A. said, equal to the five-year average for the date. A total of 2% was planted in top-producing Kansas, in line with the 2% five-year average.

Meanwhile, the 2013 spring wheat harvest surpassed the five-year average as of Sept. 8 in the six major states. The U.S.D.A. said 80% of the crop was harvested in the latest week, just above the 79% five-year average for the date. Progress was ahead of average in every state except top-producing North Dakota, where 73% of the crop was harvested, modestly below the 78% average.