The 2018 corn crop is on the fast track to harvest, in fact in many areas it’s one to two weeks ahead of average. Will that influence how USDA’s August yield estimate is calculated? The short answer: not really.
Every year, USDA collects as much information as they can in the field, according to Pro Farmer editor Brian Grete.
“If there’s harvestable grain out there, they will weigh it,” he says. “They always do the same methodology. They will do what they can in the field. So, if it's pushed ahead and it's ready to harvest, well now it's harvestable grain and they can weigh it. If it's not, then they put on an average ear weight.”
So while they might weigh more ears than they normally do when estimating yield for the August report, their methodology will not change.
Here’s a refresher on how USDA figures their yield estimates, according to USDA NASS.
Survey procedures: Objective yield and farm operator surveys are conducted. Last year, those surveys were between July 25 and August 4 to gather information on expected yields as of August 1. The objective yield surveys for corn, cotton, soybeans, and wheat were conducted in the major producing states that usually account for about 75 percent of the United States production.
Farm operators were interviewed to update previously reported acreage data and seek permission to randomly locate two sample plots in selected fields for the objective yield survey. The counts made within each sample plot depend on the crop and the maturity of that crop.
In all cases, the number of plants is recorded along with other measurements that provide information to forecast the number of ears, bolls, pods, or heads and their weight. The counts are used with similar data from previous years to develop a projected biological yield. The average harvesting loss is subtracted to obtain a net yield.
The plots are revisited each month until crop maturity when the fruit are harvested and weighed. After the farm operator has harvested the sample field, another plot is sampled to obtain current year harvesting loss.
The farm operator survey was conducted primarily by telephone with some use of mail, internet, and personal interviews.
In 2017, approximately 21,700 producers were interviewed during the survey period and asked questions about probable yield. These growers were surveyed throughout the growing season to provide indications of average yields.