Corn Harvest Quality Report 2017/2018

I. Harvest Quality Highlights

The overall quality of the 2016 corn crop was better than the average of the previous five crop years (5YA¹) on most attributes, with 87.8% of the samples meeting the standards for U.S. No. 2 grade or better. In addition to desirable average levels of grade factors, the 2016 U.S. corn crop is entering the market channel with higher average test weight, kernel volume, oil concentration, and whole kernels, and lower broken corn and foreign material and stress cracks relative to the 5YA.

The good quality was largely the result of a favorable corn growing season with earlier than normal planting; a warm, dry vegetative period; and a warm and wet grain filling period and harvest. U.S. corn producers experienced record high yields in 2016, resulting in the largest U.S. corn crop on record. Total U.S. corn production for 2016 is projected to be 386.8 million metric tons (15.23 billion bushels), an 11.95% increase in production over the 2015 corn crop. The United States is the top exporter of corn, with an estimated 39.2% of global corn exports during the 2016/2017 marketing year.

Grade Factors and Moisture

  • Average test weight of 58.3 lb/bu (75.0 kg/hl), with 94.9% above the limit for No. 1 grade corn, and 99.5% above the limit for No. 2 grade. Higher than 2015 and 5YA, this test weight indicates good kernel filling and maturation
  • Low levels of broken corn and foreign material (BCFM) (0.7%), with 96.6% below the limit for No. 1 grade, indicating little cleaning will be required.
  • Average total damage of 2.6%, higher than 2015, 2014, and 5YA. While 89.3% of the samples were below the limit for No. 2 grade, some care should be given to monitoring and properly aerating corn for safe storage.
  • No observed heat damage.
  • Higher elevator moisture content (16.1%) than 2015, yet same as 5YA. The distribution shows 33.1% of the samples were below 15% moisture content, and only 28.4% of the samples were above 17% moisture content. This distribution indicates more samples required drying than in 2015, but still less than in 2014.

Chemical Composition

  • Higher protein concentration (8.6% dry basis) than 2015 and 2014, but slightly lower than 5YA.
  • Lower starch concentration (72.5% dry basis) than 2015, 2014, and 5YA.
  • Average oil concentration of 4.0% (dry basis), higher than 2015, 2014, and 5YA.

Physical Factors

  • Low percentage of stress cracks (4%) and stress crack index (8.8), slightly higher than 2015, but below 2014 and 5YA, with 91.7% of samples having stress cracks less than 10%. The low percentage of stress cracks is likely due to excellent field dry-down conditions at harvest with less artificial drying needed than in wetter years. Susceptibility to breakage should remain relatively low.
  • Higher 100-k weight (35.20 g) than 2015, 2014, and 5YA, signifying larger kernels than in previous years.
  • Average kernel volumes of 0.28 cm³, slightly higher than 2015, 2014, and 5YA.
  • Average true density of 1.258 g/cm³, higher than 2015, similar to 2014, and lower than 5YA.
  • Similar average horneous endosperm (79%) to 2015, but lower than 2014 and 5YA, indicating softer kernels compared to 2014 and 5YA.
  • Higher average whole kernels (95.2%) than 2015, 2014, and 5YA. The high percentage of whole kernels and relatively low stress cracks indicate the corn should have fewer broken kernels during handling than in previous years.


  • All but one sample, or 99.4%, of the 2016 corn samples tested below the FDA action level of 20 ppb.
  • In 2016, 100% of the corn samples tested below the 5 ppm FDA advisory level for DON (same as in 2015 and 2014). However, there were more samples showing levels of DON above the FGIS “Lower Conformance Level” in 2016 than in 2015 and 2014. This increase may be attributed to the wet weather conditions, which were more conducive to DON development in 2016 than in the previous two years.

¹5YA represents the simple average of the quality factor’s average or standard deviation from the 2011/2012, 2012/2013, 2013/2014, 2014/2015, and 2015/2016 Harvest Reports.