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Corn Harvest Quality Report 2012/2013

Contents

  1. Harvest Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Moisture
  5. Chemical Composition
  6. Physical Factors
  7. Mycotoxins
  8. Crop and Weather Conditions
  9. Planting and Early Growth Conditions - Spring (March-May)
  10. Pollination and Grain Fill Conditions - Summer (June-August)
  11. Harvest Conditions (August-October +)
  12. U.S. Corn Production, Usage, Outlook
  13. U.S. Corn Use and Ending Stocks
  14. Outlook
  15. Survey and Statistical Analysis Methods
  16. Survey Design and Sampling
  17. Statistical Analysis
  18. Testing Analysis Methods
  19. Corn Grading Factors
  20. Moisture
  21. Chemical Composition
  22. Physical Factors
  23. Mycotoxin Testing
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III. QUALITY TEST RESULTS

A. Grade Factors

The U.S. Department of Agriculture’s Federal Grain Inspection Service (FGIS) has established numerical grades, definitions and standards for measurement of many quality factors. The attributes which determine the numerical grades are test weight, broken corn and foreign material (BCFM), total damage, and heat damage. The corn grades and grade requirements are summarized in the “U.S. Corn Grades and Conversions” section on page 45.

1. Test Weight

Test weight (weight per volume) is a measure of bulk density and is often used as a general indicator of overall quality and as a gauge of endosperm hardness for alkaline cookers and dry millers. High test weight corn will take up less storage space than the same weight of corn with a lower test weight. Test weight is initially impacted by genetic differences in the structure of the kernel. However, it is also affected by moisture content, method of drying, physical damage to the kernel (broken kernels and scuffed surfaces), foreign material in the sample, kernel size, stress during the growing season, and microbiological damage. When sampled and measured at the point of delivery from the farm at a given moisture content, high test weight generally indicates high quality, high percent of horneous (or hard) endosperm and sound, clean corn. Test weight is highly correlated to true density and reflects kernel hardness and kernel maturity.

HIGHLIGHTS

  • The U.S. Aggregate average test weight of 58.8 lb/bu (75.6 kg/hl) indicates overall good quality and is more than 2 lb/bu above the grade limit for U.S. No. 1 corn (56 lbs).
  • Average test weight in 2012 was higher than in 2011 in all ECAs, and all samples were above the grade limit for U.S. No. 1.
  • Values for individual samples ranged from 49.4 to 62.5 lb/bu, with a standard deviation of 1.21, below that of the 2011 crop indicating less variability in the samples tested.
  • Test weight values were distributed with 99.4% of the samples above the factor limit for U.S. No. 2 grade and 96.1% above the No. 1 limit of 56 lb/bu.
  • As corn is commingled moving through the marketing channel, the average test weight in each ECA is not likely to fall below the minimum for U.S. No. 2 grade.
  • Uniformity of samples was greater in the 2012 crop relative to values in the 2011 crop as indicated by the lower standard deviation in all ECAs.

2. Broken Corn and Foreign Material (BCFM)

Broken corn and foreign material (BCFM) is an indicator of the amount of clean, sound corn available for feed and processing. The lower the percentage of BCFM, the less foreign material and/or fewer broken kernels are in a sample. Higher levels of BCFM in farmoriginated samples generally stem from combine settings and/or weed seeds in the field.

Broken corn is defined as everything small enough to pass through a 12/64th inch roundhole sieve, but too large to pass through a 6/64th inch round-hole sieve.

Foreign material is defined as any non-corn pieces too large to pass through a 12/64th inch round-hole sieve, as well as all fine material small enough to pass through a 6/64th inch round-hole sieve.

HIGHLIGHTS

  • Average BCFM for the U.S. Aggregate was 0.8% compared to 1.0% in 2011.
  • Uniformity of samples was greater in the 2012 crop relative to values in the 2011 crop as indicated by the lower standard deviation in all ECAs.
  • BCFM U.S. Aggregate values ranged from 0.1 to 5.7% with a standard deviation of 0.53% compared to 0.65% in 2011. None of the ECAs differed substantially from the U.S. Aggregate.
  • BCFM U.S. Aggregate values were distributed with 94.5% of the samples containing 2% or less.
  • BCFM levels in almost all (98.6%) of the corn samples were well below the maximum of 3% allowed for U.S. No. 2 corn.
  • BCFM levels will normally increase during drying and handling, depending on the methods used and the soundness of the kernels.

3. Broken Corn

Broken corn is more subject to mold and insect damage than whole kernels and can cause problems in handling and processing. When not spread or stirred in a storage bin, broken corn tends to stay in the center of the bin while whole kernels are likely to gravitate to the outer edges. This phenomenon is known as a “spoutline” in the grain business. In some cases, most, if not all, of the spoutline can be removed by pulling grain out of the center draw.

HIGHLIGHTS

  • Broken corn in the U.S. Aggregate values averaged 0.7% in 2012 (0.8% in 2011).
  • These low levels suggest the corn will store and handle well in the market channel.
  • Broken corn in the U.S. Aggregate values ranged from 0 to 4.8% with a standard deviation of 0.42% (0.52% in 2011) indicating slightly less variability than in 2011.
  • Broken corn U. S. Aggregate values were distributed with 38.3% less than 0.5% and 78.5 % less than 1.0% broken corn.
  • Broken corn average values in the individual ECAs in 2012 were the same as the U.S. Aggregate.
  • The distribution chart to the right, displaying broken corn as a percent of BCFM, shows that in nearly all samples, BCFM consisted primarily of broken corn.

4. Foreign Material

Foreign material is of importance in that it has little feed or processing value, it is generally higher in moisture content than the corn and therefore creates a potential for deterioration of corn during storage. Foreign material also contributes to the spoutline and is more serious than broken corn because of the higher moisture level as mentioned above.

HIGHLIGHTS

  • Foreign material in the U.S. Aggregate averaged 0.2% in 2012 (the same as in 2011) and 94.5% of the samples contained less than 0.5% FM.
  • All ECAs had average foreign material values equal to or less than 0.2%, differing little from the 2011 crop.
  • High levels of foreign material found in a few of the samples can be readily cleaned to minimize any significant handling problems.
  • Variability among the U.S. Aggregate samples in 2012 was less than in 2011 with a standard deviation of 0.18% in 2012 compared to 0.20% in 2011.

5. Total Damage

Total damage is the percentage of kernels and pieces of kernels that are visually damaged in some way, including damage from heat, frost, insect, sprout, disease, weather, ground, germ, and mold. Most of these types of damage result in some sort of discoloration or change in kernel texture. Damage does not include broken pieces of grain that are otherwise normal in appearance.

Mold damage is usually associated with higher moisture content and high temperature in growing and/or storage. Mold damage and the associated potential for mycotoxins is the damage factor of greatest concern. Mold damage can occur prior to harvest as well as during temporary storage at high moisture and high temperature levels before delivery.

HIGHLIGHTS

  • Total damage in the U.S. Aggregate samples averaged 0.8% in 2012 (1.1% in 2011) indicating good quality at harvest.
  • Total damage in the U.S. Aggregate samples ranged from 0.0 to 12.7% with a standard deviation of 0.72% indicating greater uniformity among samples than in 2011.
  • Total damage in the U.S. Aggregate samples were distributed with 96.5% of the samples having 3% or less damaged kernels, and 99.0% having less than 5%.
  • Total damage average values in Gulf, Pacific Northwest, and Southern Rail ECAs were 0.9%, 0.5%, and 0.7% respectively. These levels are well below the limit for U.S. No. 1 corn (3.0%) indicating that total damage was not a problem in farm deliveries.

6. Heat Damage

Heat damage is a subset of total damage and has separate allowances in the U.S. Grade standards. Heat damage can be caused by microbiological activity in warm, moist grain or by high heat applied during drying. Heat damage is seldom present in corn delivered at harvest directly from farms.

HIGHLIGHTS

  • There was no heat damage reported in any of the samples, the same results as in 2011.
  • The absence of heat damage likely was due in part to fresh samples coming directly from farm to elevator with minimal prior drying.