USDA had already set the bar high projecting the 2020 U.S. corn yield at a record 178.5 bushels per acre (bpa) but as the first crop production report gets closer August 12, a number of private estimates are exceeding that, some by significant margins.
A fast start to plantings, the loss of five million acres between the March intentions and June acreage report concentrated in some of the lower yielding states, and generally favorable weather so far this growing season has traders asking how big is big.
Often end of July crop ratings are used to project yields, or more specifically, what percent do they deviate from let's say the 30-year trend.
Depending on which data set you use, the correlation between end July corn crop ratings and the percent yields deviate from trend can be anywhere from 70-80%.
Along these lines this chart shows the end of July crop ratings for each of the top 18 corn producing states and the U.S. for this year, last year and then the 1986-2020 average.
We use our usual ratings system where we weight the crop based on the percent in each category and assign that category a factor of 2 for very poor, 4 for poor, 6 for fair, 8 for good, and 10 for excellent and then sum the results.
Also shown is where this year's end of July corn rating ranks over the past 20 years where a 1 means the highest rating since 2000 and 20 means the lowest rating over the past 20 years as denoted by the number in the yellow boxes.
Given that 2019 had a number of weather challenges, primarily record rainfall, all but 4 of the top 18 states have end of July conditions better than a year ago.
Colorado shows the largest drop vs. year ago levels as they and Texas, another underperformer, have seen drought in much of the Central and Southern Plains this year.
The Pennsylvania crop is down sharply as that state has been hurt by persistent dryness that has also plagued its neighboring state Ohio.
In fact, OH and PA along with TX and CO are the only states that have below average end of July crop ratings.
On the other hand, it doesn't appear that any state has its highest ratings ever, certainly not over the past 20-year period.
Interestingly MN, SD and WI have the best ratings at the third highest since 2000 as these states likely benefited from good rains in July when the high pressure ridge that was parked in the center of the country for a time forced any storms systems to ride up and over the ridge, giving some of the northern states decent precipitation.
Finally note that Iowa, which remains the driest state in the Corn Belt and also the largest producing one, has a crop rating above 2019 and the average with its 2020 end of July rating right in the middle of the pack.
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