Here's Why USDA's Weekly Crop Condition Ratings Aren't an Accurate Gauge of Yields

July ended on high note when it comes to temperatures. Extreme heat, and lack of rain in portions of the Midwest, meant crops in certain areas were under stress. 

The latest USDA Crop Progress Report shows as a result, the national corn condition rating dropped 2 points in a week, now at 64% good to excellent. In total, nine states saw corn conditions drop in the good to excellent Gregory, with Colorado down 9 percentage points, Kansas off by 4 points, and Nebraska dropping 5 points in a week. 

Soybean condition ratings actually improved 3 points, now rated 60% good to excellent. Conditions in Kansas, Minnesota, Missouri and Nebraska slipped last week, but even with Nebraska dropping 2 percentage points in the good to excellent category, Nebraska, Indiana Ohio, Wisconsin and the Mid-South show condition ratings that look especially promising.

Do Crop Conditions Accurately Gauge Yield?

August is a month where market analysts, traders and farmers will start to debate the possibilities of national yields. While USDA's look at crop progress numbers are posted each week, Pro Farmer says the condition ratings aren't the best indication of national yield. 

"The numbers matter because they give you a guideline," says Brian Grete, editor of Pro Farmer. "I think the best means of looking at crop conditions is the trend."

Grete says based on the trend in condition ratings this year from USDA, crop conditions have declined this year.

"At the beginning of the growing season, we were higher than where we are now. So, we've seen a decline in corn and soybean crops. I don't think that's a surprise to anybody out there. It's just a matter of how you calculate it out as a percentage decline," he adds. 

So, can you take the crop condition ratings and translate that into a national yield? According to Grete, the answer is no.

"There are all kinds of models out there that tried to do that. None of them are highly successful," he adds. 

Ground-Truthing During Pro Farmer Crop Tour 

Grete points out even USDA's August Crop Production report won't include results from yield surveys in fields, as starting last year, USDA eliminated that portion of the report. 

"They don't go out into the fields in the 10 objective yield states and pull samples anymore," he says. "So, the Pro Farmer samples will be the first ground truthing samples, and so the market is going to pay attention to that."

Grete points out the Pro Farmer Crop Tour takes ear counts and soybean pod counts, and then compares that to the three-year average. He says those are the key numbers the Pro Farmer Crop Tour produces every year during the third week of August. 

"And that's one of the things that we'll do on the pro farmer crop tour is put out the yield numbers from Crop Tour data Monday through Thursday, and then the Pro Farmer estimate which is separate on Friday, and that takes into account areas outside of what we sample on crop tour," says Grete.

The 2021 Pro Farm Crop Tour is set for Aug. 16-19. Each night, the daily findings from each leg will be broadcast live, virtually.  You can sign up to view the evening meetings here.