As the harvest is in full swing in the area, we are starting to hear yield reports, indicative of the success of this year’s harvest.
In addition to yield reports, you can also hear farmers and those in the agricultural industry discussing crop moisture and test weight. What do these numbers mean and are they important indicators of a good season?
Let’s take a closer look.
When a farmer discusses his yield, the number is given to us in bushels per acre (bu / ac). According to the USDA, the last time the data was compiled in 2019, the average corn yield in White County, Indiana was 177.6 bushels / acre, with soybeans hitting 52.8 bushels / acre. This compares to state averages of 169 bushels / acre and 51 bushels / acre, respectively for corn and soybeans for that year.
Yields will vary from year to year and from field to field due to various factors, namely weather and soil productivity, but overall these numbers give us a good average for discuss a yield that would appeal to most farmers.
As always, keep in mind that the numbers that are broadcast in a coffee shop or a bean elevator may be slightly skewed.
To put this amount of grain into perspective, keep in mind that over 80% of White County is planted with crops each year. A few more acres of corn are planted each year than soybeans, with 2019 data totaling 134,000 acres of harvested corn. At 177.6 bushels / acre, that equates to 23.8 million bushels of corn that are moved around the county in an average year!
The next number you will hear is grain moisture, which is simply the percentage of water in the grain. When ripe, the corn will have a moisture content of around 30%.
However, ideal crop moisture levels for field corn will generally be between 15% and 20%. Many farmers will start harvesting before that and dry the grain in silos before transporting it to the grain elevator, while others will wait for it to dry and bring it straight into town.
Both strategies carry some risk, as harvested “wet” corn will need to dry out quickly in storage or risk molding. Farmers who wait too long for the fields to dry are also at risk: leaving corn in the field makes it sensitive to the elements, mainly wind, which can lead to a difficult harvest.
Finally, and perhaps most confusing, we have the specific gravity of the kernels. Test weight measures the amount of grain that will go into a bushel. Dried corn weighs 56 pounds per bushel, while ready-to-market soybeans weigh 60 pounds per bushel.
Is this number important? Yes, but it is not a performance indicator. Farmers like to see higher test weights as this can be an indicator of the quality of the grain and factors in the amount of grain they sell by truck.
For example, there are more bushels of corn with a test weight of 58 than the same truck carrying corn with a test weight of 54.
Many factors influence test weight including: grain moisture at time of testing, variability in hybrids, corn cob rot, and stress during grain filling in the form of disease problems , water stress and / or cold temperatures.
Andrew Westfall is Principal of Purdue Extension White County (Ind.).