As harvest approaches, USDA says the condition of the U.S. corn crop continues to deteriorate. The crop is maturing in a more or less normal fashion. Virtually all (92%) of acres are estimated to be in the dough stage or beyond. That compares with a five-year average of 92% for the first week of September. Seventy-one percent of corn acres are dented compared to a five-year average of 70%. Only 18% of acres are considered mature, where the five-year average is 20%. Those numbers are reasonably encouraging since late planting has left some of this crop susceptible to an early frost. The concerning numbers continue to be crop condition ratings, which are getting worse and worse and doing so at a very rapid pace.

Only 52% of acres were rated good or excellent this past week, down another 2% from the week before. This week’s good/excellent ratings compare to 69% last year and a 10-year average of 57.8%.

Perhaps more concerning for this year is USDA’s estimate that 21% of this year’s corn acres are in poor or very poor condition, where only 11% rated in those bottom two categories in 2010. These lower crop conditions are reflected in lower yield estimates by a number of market analysts. Informa Economics cut its estimated corn yield from 158 bu./acre to 151 last week. The reduction dropped their forecast crop to 12.711 billion bu., down from their prior estimate of 13.353. Allendale reduced its forecast yield to 147.7 bu./acre and its crop estimate to only 12.466 billion bu.

Soybean crop condition continues to decline as well, but not at nearly the pace of the corn crop. 56% of soybean acres were rated as being in either good or excellent condition last week. That compares to 57% the week before, 64% for the same week in 2010 and an average of 56.8% over the past 10 years. The soybean crop is lagging a bit in terms of maturity but it is very early to make that call as only 6% of acres, (vs. a five-year average of 13%), are dropping leaves as of last week. Informa’s most recent yield estimate is 41.5 bu./acre, down 1 bu. from their previous forecast. Allendale’s latest estimate for soybean yield is 40.7 bu./acre. USDA’s August estimate was 41.4 bu./acre.

USDA’s monthly Crop Production and World Agricultural Supply and Demand Estimates reports will be released Monday, Sept. 12.