Quality not an issue in corn crop

Quality not an issue in corn crop

Recent report indicates record corn crop with better-than-anticipated quality overall.

MANY growers and those involved in the supply chain feared a gloomy harvest outcome this fall after the delay in spring planting, but much to their surprise, the overall quality for the 2013 corn crop was good, and it was larger than the two previous years, according to the U.S. Grains Council's "Corn Harvest Quality" report released this month.

The U.S. Grains Council started publishing the corn quality reports in 2011 to assist international buyers in understanding the quality of U.S. yellow commodity corn. Upon completion of the third annual survey, patterns were observed on how the weather and growing conditions affect the quality of U.S. corn as it harvested.

The 2013-14 report — based on 610 samples of yellow commodity corn taken from 12 states, divided by export catchment area (ECA) — indicates that this year's crop had very similar characteristics to 2011, with a cooler and wetter planting season. Therefore, the 2013 corn crop mirrored the 2011 corn crop in chemical composition and starch levels — characteristics that are greatly affected by weather during the growing season.

Nevertheless, variations in the 2013 corn crop from 2011 and 2012 were noted. This year, the corn had a higher moisture level, a lower test weight and true density, softer endosperm and contained slightly more stress cracks.


Grade factors

Quality not an issue in corn crop
With grain supplies short from last year and delays in crop maturity, the harvested corn was, on average, at a 17.3% moisture level, higher than in 2012 and 2011. More than 75% of the samples taken were above 15% moisture (Figure), resulting in additional grain handling management, including an increase in drying time and aeration and careful segregation.

While test weights averaged above the limit for No. 1 grade corn at 57.9 lb./bu. and more than 93% of samples were above the No. 2 grade minimum, the average test weight was slightly lower than in 2012.

The sample values varied across the three ECAs, with the Pacific Northwest recording the lowest average at 56.5 lb./bu., the Gulf area reporting 58.1 lb./bu. and the Southern Rail reporting 58.3 lb./bu.

Similar to the past two years, low levels of broken corn and foreign material were reported. Uniformly, the samples averaged 0.7% for broken corn, with 39% of the samples having less than 0.5% and the remaining samples registering at less than 1.0%. Foreign material averaged 0.2% in 2013, which is positive for storing grain.

Total damage was reported at 0.9%, compared to 0.8% in 2012 and 1.1% in 2011. The high damage levels of a few samples were related to the high moisture content. With the average total damage in all ECAs well below the limit for U.S. No. 1 corn, total damage in farm deliveries was not an issue.


Physical factors

Taking a closer look at the actual physical qualities of the harvested crop, the amount of whole kernels was slightly lower than in the last two years, at 92.5%, which resulted in more stress cracks, averaging 9%. Still, the quality of the corn crop was more than adequate for long-term storage.

The 2013 corn crop should be good for wet milling and feeding, with the average true densities and horneous endosperm indicating moderate hardness. Moderate to hard endosperm corn also is available for dry milling if selected properly.

On the whole, mycotoxins were not a wide concern like they were last year. Approximately 99.4% of the sampled corn tested below the 20 parts per billion Food & Drug Administration aflatoxin action level. In addition, all corn samples were below the FDA advisory level for deoxynivalenol, which is 5 ppm for hogs and other animals and 10 ppm for chickens and cattle.


Chemical composition

The corn samples had an average protein content of 8.7% on a dry basis — the same level as in 2011 but lower than in 2012. The available nitrogen in 2012 was distributed over fewer bushels per acre, resulting in corn having a higher protein content than this year.

The results showed that 48.9% of the samples had a protein content between 8.00% and 8.99%, while 26.2% were in a range of 9.00-9.99% and 7.4% were at 10% or higher.

A starch content of 73.5%, on a dry basis, was significantly higher this year and may indicate good kernel filling, which is desirable for corn wet milling. The range for starch was 71.1-75.9%.

The average oil content, at 3.7% on a dry basis, was virtually unchanged from the past two years. There was little variation in oil content across the ECAs, with the Gulf at 3.7%, the Pacific Northwest at 3.5% and the Southern Rail at 3.7%.

Volume:85 Issue:53

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